the Approved Document F - Ventilation 2010 edition incorporating further 2010 amendments

the Approved Document F - Ventilation 2010 edition incorporating further 2010 amendments
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Building Regulations 2010
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The Building Regulations 2010
Ventilation
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ONLINE VERSION
ONLINE VERSION
MAIN CHANGES IN THE
VENTILATION REQUIREMENTS
FOR BUILDINGS IN 2010
1. This edition of Approved Document F,
Ventilation, replaces the 2006 edition and
comes into force on 1 October 2010.
2. The following are the main changes to the
legal requirements in the Building Regulations
2010 and the Building (Approved Inspectors
etc) Regulations 2010, and in the technical
guidance in Approved Document F.
Changes in the legal requirements
3. All fixed mechanical ventilation systems, where
they can be tested and adjusted, shall be
commissioned and a commissioning notice
given to the Building Control Body.
Main changes made by the
2010 amendments
This 2010 edition, incorporating the further 2010
amendments reflects the changes made as a result
of the Building Regulations 2010 and Building
(Approved inspector etc) Regulations 2010. The
changes mainly reflect regulation number changes
as a result of re-ordering. There have been no
amendments to the substantive requirements
in Schedule 1 (i.e. Parts A to P) of the Building
Regulations.
Please note the simplification of the definition of
‘room for residential purposes’ in regulation 2 of
the Building Regulations 2010. Please also note
that L1(c) has now become regulation 40.
4. For mechanical ventilation systems installed in
new dwellings, air flow rates shall be measured
on site and a notice given to the Building
Control
Body. This shall apply to intermittently-used
extract fans and cooker hoods, as well as
continuously running systems.
APPROVED DOCUMENTS
The following documents have been approved
and issued by the First Secretary of State for the
purpose of providing practical guidance with
respect to the requirements of the Building
Regulations 2010.
Approved Document A: Structure
2004 edition incorporating 2010 amendments
Approved Document B (Fire safety) – Volume
1: Dwellinghouses
2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) – Volume
2: Buildings other than dwellinghouses
2006 edition incorporating 2007 and 2010
amendments
Approved Document C: Site preparation and
resistance to contaminants and moisture
2004 edition incorporating 2010 amendments
Approved Document D: Toxic substances
1992 edition incorporating 2002 and 2010
amendments
Approved Document E: Resistance to the
passage of sound
2003 edition incorporating 2004 and 2010
amendments
Approved Document K: Protection from falling
collision and impact
1998 edition incorporating 2000 and 2010
amendments
Approved Document L1A: Conservation of
fuel and power – New dwellings
2010 edition incorporating further 2010 amendments
Approved Document L1B: Conservation of
fuel and power – Existing dwellings
2010 edition incorporating further 2010 and 2011
amendments
Approved Document L2A: Conservation of
fuel and power – New buildings other than
dwellings
2010 edition incorporating further 2010 amendments
Approved Document L2B: Conservation of
fuel and power – Existing buildings other than
dwellings
2010 edition incorporating further 2010 and 2011
amendments
Approved Document M: Access to and use of
buildings
2004 edition incorporating 2010 amendments
Approved Document F: Ventilation
2010 edition incorporating further 2010 amendments
Approved Document N: Glazing – safety in
relation to impact, opening and cleaning
1998 edition incorporating 2000 and 2010
amendments
Changes in the technical guidance
Approved Document G: Sanitation, hot water
safety and water efficiency
2010 edition incorporating further 2010 amendments
Approved Document P: Electrical safety –
Dwellings
2006 edition incorporating 2010 amendments
6. Ventilation provisions have been increased for
dwellings with a design air permeability tighter
than or equal to 5 m3/(h.m2) at 50 Pa.
Approved Document H: Drainage and waste
disposal
2002 edition incorporating 2010 amendments
Approved Document to support regulation 7:
Materials and workmanship
1999 edition incorporating 2010 amendments
7. For passive stack ventilators, the stack
diameter has been increased to 125 mm for all
room types. Use of passive stack ventilation in
inner wet rooms has been clarified.
Approved Document J: Combustion
appliances and fuel storage systems
2010 edition incorporating further 2010 amendments
5. The owner shall be given sufficient information
about the ventilation system and its
maintenance
requirements so that the ventilation system can
be operated to provide adequate air flow.
8. The guidance for ventilation when a kitchen
or bathroom in an existing dwelling is
refurbished has been clarified.
9. Reference is made to a new Domestic ventilation
compliance guide for guidance on installing,
inspecting, testing and commissioning
ventilation systems in dwellings. Guidance in
Appendices D and E of the 2006 edition of
Approved Document F, on installing passive
stack ventilators and fans in dwellings, can
now be found in Section 2 of the new guide.
ONLINE VERSION
ONLINE VERSION
F
Contents
PAGE
Section 1: Introduction
What is an Approved Document?
Consideration of technical risk
How to use this Approved Document
Where you can get further help
Responsibility for compliance
2
2
2
2
3
3
Section 2: The Requirements
LIMITATIONS ON REQUIREMENTS
4
6
Section 3: General guidance
Key terms
Types of work covered by this
Approved Document
Exemptions
Notification of work covered by the
ventilation requirements
Historic and traditional buildings
Material change of use
Live–work units
Mixed use developments
Materials and workmanship
Independent certification schemes
Standards and technical specifications
The Workplace (Health, Safety and
Welfare) Regulations 1992
7
7
9
9
9
10
11
11
11
11
12
12
12
Section 4: Introduction to the provisions
Performance
The purpose of ventilation
Types of ventilation
The ventilation strategy adopted in
Approved Document F
Control of ventilation
Performance-based guidance
Equivalent area of ventilators
Ventilation effectiveness
Source control
Noise
Fire precautions
Modular and portable buildings
Installation of ventilation systems
Air flow rate testing and commissioning
of ventilation systems
Provision of information
13
13
13
13
Section 5: New dwellings
Introduction to provisions
Ventilation rates
Ventilation systems for dwellings without
basements
Ventilation systems for basements
Ventilation of a habitable room through
another room or a conservatory
19
19
20
Approved Document F
14
15
15
15
16
16
16
17
17
17
17
18
20
31
PAGE
Section 6: New buildings other
than dwellings
General
Access for maintenance
Offices
Ventilation of other types of building
Ventilation of car parks
Alternative approaches for ventilation
of car parks
33
33
33
33
35
38
38
Section 7: Work on existing buildings
39
General
39
Addition of a habitable room (not including
a conservatory) to an existing dwelling
39
Addition of a wet room to an
existing dwelling
40
Addition of a conservatory to an
existing building
40
Refurbishing a kitchen or bathroom in
an existing dwelling
40
Section 8: Standards and other
publications
Standards
Other publications
41
41
41
Appendix A: Performance-based ventilation
Introduction
Performance criteria for dwellings
Assumptions used in applying performance
criteria for dwellings in Section 5
Performance criteria for buildings other
than dwellings
Assumptions used in applying performance
criteria for offices in Section 2
References
43
43
43
Appendix B: Purge ventilation
Introduction
Windows
External doors (including patio doors)
Further information
47
47
47
47
48
Appendix C: Example calculations for
ventilation sizing for dwellings
Introduction
Details of ground-floor flat
Details of semi-detached house
49
49
49
52
Appendix D: Minimising ingress of external
pollution into buildings in urban areas
Control of ventilation intakes
Location of exhaust outlets
References
55
55
56
56
Index
57
43
45
45
46
31
ONLINE VERSION
Ventilation
1
F
ONLINE VERSION
Section 1: Introduction
What is an Approved Document?
1.1
This document has been approved by the
Secretary of State to provide practical guidance
on ways of complying with the requirements in
Part F of Schedule 1 to, and regulations 39, 42
and 44 (in so far as it relates to fixed systems
for mechanical ventilation) of, the Building
Regulations 2010 (SI 2010/2214) for England
and Wales, and regulations 20(1) and 20(6) (in so
far as it relates to fixed systems for mechanical
ventilation) of the Building (Approved Inspectors
etc) Regulations 2010 (SI 2010/2215) for England
and Wales. The Building Regulations 2010
and the Building (Approved Inspectors etc)
Regulations 2010 are referred to throughout
the remainder of this document as ‘the Building
Regulations’ and ‘the Approved Inspectors
Regulations’ respectively.
1.2
The intention of issuing Approved
Documents is to provide guidance about
compliance with specific aspects of building
regulations in some of the more common
building situations. They set out what, in ordinary
circumstances, may be accepted as reasonable
provision for compliance with the relevant
requirement(s) of building regulations to which
they refer.
1.3
If guidance in an Approved Document
is followed there will be a presumption of
compliance with the requirement(s) covered by
the guidance. However, this presumption can
be overturned, so simply following guidance
does not guarantee compliance; for example,
if the particular case is unusual in some way,
then ‘normal’ guidance may not be applicable.
It is also important to note that there may well
be other ways of achieving compliance with the
requirements. There is therefore no obligation
to adopt any particular solution contained
in this Approved Document if you would
prefer to meet the relevant requirement in
some other way. Persons intending to carry
out building work should always check with
their Building Control Body, either the local
authority or an approved inspector, that their
proposals comply with building regulations.
1.4
It is important to note that this Approved
Document, as well as containing guidance,
also contains extracts from the Regulations.
Such regulatory text must be complied with
as stated. The guidance contained in this
Approved Document relates only to the particular
requirements of building regulations that the
document addresses (set out in Section 2).
However, building work may be subject to more
than one requirement of building regulations. In
such cases the work will also have to comply
with any other applicable requirements of
building regulations.
Ventilation
2
1.5
There are Approved Documents that give
guidance on each of the Parts of Schedule 1 and
on regulation 7. A full list of these is provided at
the back of this document.
Consideration of technical risk
1.6
The construction of new buildings,
and building work to existing buildings, must
satisfy all the technical requirements set out
in the Building Regulations. When considering
the incorporation of ventilation measures in
dwellings, attention should also be paid in
particular to the need to comply with Part B (fire
safety), Part C (site preparation and resistance to
contaminants and moisture), Part E (resistance
to the passage of sound), Part L (conservation of
fuel and power), Part J (combustion appliances
and fuel storage systems) and Part P (electrical
safety), as well as Part F. The adoption of any
particular ventilation measure should not involve
unacceptable technical risk of, for instance,
creating a cold bridge. Designers and builders
should refer to the relevant Approved Documents
and to other generally available good practice
guidance to help minimise these risks.
How to use this Approved
Document
1.7
This Approved Document is subdivided
into eight sections as detailed below.
This introductory section sets out the general
context in which the guidance in the Approved
Document must be considered.
Section 2 sets out the relevant legal
requirements as published in the Building
Regulations.
Section 3 contains key terms and general
guidance on the types of building work covered
by Approved Documents, how to deal with
‘special’ areas of buildings that contain dwellings,
procedures for notifying work, materials and
workmanship, certification and standards, and
health and safety issues.
Section 4 details the principles of ventilation and
its control.
Section 5 details the guidance for ventilation of
dwellings.
Section 6 details the guidance for ventilation of
buildings other than dwellings.
Section 7 details the guidance for ventilation of
existing buildings.
Section 8 lists standards and other publications
referred to in the text.
Note. A reference to a publication is likely to
be made for one of two main reasons: either
the publication contains additional or more
comprehensive technical detail, which it
ONLINE VERSION
Approved Document F
ONLINE VERSION
would be impractical to include in full in the
Approved Document but which is needed to
fully explain ways of meeting the requirements;
or it is a source of more general information.
The reference will be to a specified edition of
the document. The Approved Document may
be amended from time to time to include new
references or to refer to revised editions where
this aids compliance.
1.8
In this document the following conventions
have been adopted to assist understanding and
interpretation:
F
Responsibility for compliance
1.10 It is important to remember that if you
are the person (e.g. designer, builder, installer)
carrying out building work to which any
requirement of building regulations applies you
have a responsibility to ensure that the work
complies with any such requirement. The building
owner may also have a responsibility for ensuring
compliance with building regulation requirements
and could be served with an enforcement notice
in cases of non-compliance.
a. Regulations extracted from the Building
Regulations or the Approved Inspectors
Regulations as amended are printed against
a green background. There is a legal
obligation to comply with the requirements in
these regulations. In contrast, the technical
guidance in the Approved Document
shows one or more ways of complying with
ventilation requirements in typical situations.
b. Key terms are defined in paragraph 3.1 and
are printed in bold italic text.
c. Additional commentary in italic text
appears after some numbered paragraphs.
This commentary is intended to assist
understanding of the preceding paragraph
or sub-paragraph, or to direct readers to
sources of additional information, but is not
part of the technical guidance itself.
Where you can get further help
1.9
If you do not understand the technical
guidance or other information set out in this
Approved Document and the additional detailed
technical references to which it directs you, there
are a number of routes through which you can
seek further assistance:
•
the CLG website: www.communities.gov.uk;
•
the Planning Portal website:
www.planningportal.gov.uk;
•
if you are the person undertaking the building
work you can seek assistance either from
your local authority building control service or
from your approved inspector (depending on
which building control service you are using,
or intend to use, to certify compliance of your
work with the requirements of the Building
Regulations);
•
businesses registered with a competent
person self-certification scheme may be able
to get technical advice from their scheme
operator;
•
if your query is of a highly technical nature
you may wish to seek the advice of a
specialist, or industry technical body, in the
area of concern.
Approved Document F
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Ventilation
3
ONLINE VERSION
F1
Section 2: The Requirements
2.1
This Approved Document, which takes
effect on 1 October 2010, deals with the
requirements of Part F: Ventilation of Schedule
1 to, and regulations 39, 42 and 44 (in so far
as it relates to fixed systems for mechanical
ventilation) of, the Building Regulations, as
amended. It also deals with regulations 20(1)
and 20(6) (in so far as it relates to fixed systems
for mechanical ventilation) of the Approved
Inspectors Regulations, as amended.
Requirement
Limitsonapplication
Means of ventilation
Requirement F1 does not apply to a building or space within
a building:
F1(1). There shall be adequate means of ventilation provided
for people in the building.
(2). Fixed systems for mechanical ventilation and any
associated controls must be commissioned by testing and
adjusting as necessary to secure that the objective referred to
in sub-paragraph (1) is met.
a. into which people do not normally go; or
b. which is used solely for storage; or
c. which is a garage used solely in connection with a single
dwelling.
Requirements in the Building Regulations 2010
Information about ventilation
39.—(1) This regulation applies where Part F1(1) of Schedule 1 imposes a requirement in relation to building work.
(2) The person carrying out the work shall not later than five days after the work has been completed give sufficient information to
the owner about the building’s ventilation system and its maintenance requirements so that the ventilation system can be operated
in such a manner as to provide adequate means of ventilation.
Mechanical ventilation air flow rate testing
42.—(1) This regulation applies where paragraph F1(1) of Schedule 1 imposes a requirement in relation to the creation of a new
dwelling by building work.
(2) The person carrying out the work shall, for the purpose of ensuring compliance with paragraph F1(1) of Schedule 1—
(a)
ensure that testing of the mechanical ventilation air flow rate is carried out in accordance with a procedure
approved by the Secretary of State; and
(b)
give notice of the results of the testing to the local authority.
(3) The notice referred to in paragraph (2)(b) shall—
(a)
record the results and the data upon which they are based in a manner approved by the Secretary of State; and
(b)
be given to the local authority not later than five days after the final test is carried out.
Commissioning
44.—(1) This regulation applies to building work in relation to which paragraph F1(2) of Schedule 1 imposes a requirement, but
does not apply to the provision or extension of any fixed system for mechanical ventilation or any associated controls where testing
and adjustment is not possible.
(2) This regulation applies to building work in relation to which paragraph L1(b) of Schedule 1 imposes a requirement, but does
not apply to the provision or extension of any fixed building service where testing and adjustment is not possible or would not
affect the energy efficiency of that fixed building service.
(3) Where this regulation applies the person carrying out the work shall, for the purpose of complying with paragraph F1(2) or
L1(b) of Schedule 1, give to the local authority a notice confirming that the fixed building services have been commissioned in
accordance with a procedure approved by the Secretary of State.
(4) The notice shall be given to the local authority –
(a) not later than the date on which the notice required by regulation 16(4) is required to be given; or
(b) where the regulation does not apply, not more than 30 days after the completion of the work.
Ventilation
4
ONLINE VERSION
Approved Document F
ONLINE
THE REquIREMENTS
IREMENTS
VERSION
F1
Requirements in the Building (Approved Inspectors) Regulations 2010.
Application of Provisions of the Principle Regulations.
20.—(1) Regulation 20 (provisions applicable to self-certification schemes), 27 CO2 emmission rate calculations), 29 (energy
performance certificates), 37 (wholesome water consumption calculation), 41 (sound insulation testing), 42 (mechanical ventilation
air flow rate testing), 43 (pressure testing) and 44 (commissioning) of the Principal Regulations apply in relation to building work
which is the subject of an initial notice as if references to the local authority were references to the approved inspector.
(6) Regulation 44 of the Principal Regulations applies in relation to building work which is the subject of an initial notice as if for
paragraph (4) there were substituted—
“(4) The notice shall be given to the approved inspector—
(a)
subject to sub-paragraphs (b) and (c), not later than five days after completion of the work to which the initial
notice relates;
(b)
where regulation 17 of the Building (Approved Inspectors etc.) Regulations 2010 applies, not later than the date on
which the initial notice ceases to be in force or, if earlier, the end of the period referred to in sub-paragraph (a);
(c)
where regulation 20 applies by virtue of regulation 20 of the Building (Approved Inspectors etc.) Regulations
2010, not later than the date on which the notice or certificate required by that regulation must be given.”.
Approved Document F
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Ventilation
5
F1
ONLINE
THE REquIREMENTS
IREMENTS
VERSION
LIMITATION ON REQUIREMENTS
2.2
In accordance with regulation 8 of the
Building Regulations, the requirements in Parts A
to D, F to K and N and P (except for paragraphs
G2, H2 and J7) of Schedule 1 to the Building
Regulations do not require anything to be done
except for the purpose of securing reasonable
standards of health and safety for persons in
or about buildings (and any others who may be
affected by buildings or matters connected with
buildings).
2.3
Paragraph G2 is excluded as it deals with
water efficiency and paragraphs H2 and J7 are
excluded from regulation 8 because they deal
directly with prevention of the contamination of
water. Parts E and M (which deal, respectively,
with resistance to the passage of sound and
access to and use of buildings) are excluded
from regulation 8 because they address the
welfare and convenience of building users.
Part L is excluded from regulation 8 because it
addresses the conservation of fuel and power.
Ventilation
6
ONLINE VERSION
Approved Document F
ONLINE VERSION
Section 3: General guidance
Key terms
3.1
The following are key terms used in this
document:
F1
Diagram 1 Provisions for background
ventilation
Air permeability is the physical property used
to measure the airtightness of the building fabric.
It is defined as air leakage rate per hour per
square metre of envelope area at a test reference
pressure differential across the building envelope
of 50 Pascal (50 N/m2). The design air permeability
is the target value set at the design stage.
Airtightness is a general descriptive term for
the resistance of the building envelope to
infiltration with ventilators closed. The greater
the airtightness at a given pressure difference
across the envelope, the lower the infiltration.
Automatic control is where a ventilation device
is opened and closed or switched on and off or
its performance is adjusted by a mechanical or
electronic controller which responds to a relevant
stimulus. That stimulus is usually related to the
humidity of the air in a room, pollutant levels
(e.g. carbon dioxide concentration in a room),
occupancy of the space (e.g. using a passive
infra-red motion detector) or pressure difference
across the device (e.g. due to the wind outside).
Background ventilator is a small ventilation
opening designed to provide controllable whole
building ventilation. See Diagram 1.
Basement (in relation to dwellings) is a dwelling,
or a usable part of a dwelling (i.e. a habitable
room), that is situated partly or entirely below
ground level. Note that a cellar is distinct from
a basement in that it is used only for storage,
heating plant or purposes other than habitation.
Bathroom is a room containing a bath or shower
and, in addition, can also include sanitary
accommodation.
BCB or Building Control Body is a local
authority or an approved inspector.
Cellar is a part of a dwelling which is situated
partly or entirely below ground level, and is
distinct from a basement in that it is used only
for storage, heating plant or purposes other than
habitation.
Closable opening is a ventilation opening
which may be opened and closed under either
manual or automatic control.
Common space is a space where large numbers
of people are expected to gather, such as a
shopping mall or cinema/theatre foyer. For the
purposes of this Approved Document, a space
used solely or principally for circulation (e.g. a
corridor or lift lobby in an office building or blocks
of flats) is not a common space.
Approved Document F
Continuous operation is where a mechanical
ventilation device runs all the time, e.g.
mechanical extract ventilation (MEV) and
mechanical ventilation with heat recovery
(MVHR). The air flow rate provided by the
mechanical ventilation need not be constant
but may be varied, under either manual or
automatic control, in response to the demand
for pollutant or water vapour removal.
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Ventilation
7
F1
ONLINE
GENERAL GuIDANCE
IDANCE
VERSION
Equivalent area is a measure of the
aerodynamic performance of a ventilator. It is
the area of a sharp-edged circular orifice which
air would pass through at the same volume
flow rate, under an identical applied pressure
difference, as the opening under consideration.
Purpose-provided ventilation is that part
of the ventilation of a building provided by
ventilation devices designed into the building
(e.g. via background ventilators, PSV, extract
fans, mechanical ventilation or air-conditioning
systems).
Extract ventilation is the removal of air directly
from a space or spaces to outside. Extract
ventilation may be by natural means (e.g. by
passive stack ventilation) or by mechanical
means (e.g. by an extract fan or central system).
Sanitary accommodation is a space containing
one or more water closets or urinals. Sanitary
accommodation containing one or more
cubicles counts as a single space if there is free
circulation of air throughout the space.
Free area is the geometric open area of a
ventilator.
Stack effect is the pressure differential between
inside and outside a building caused by
differences in the density of the air due to an
indoor/outdoor temperature difference.
Gross internal volume is the total internal
volume of the heated space, including the
volume of all furniture, internal walls, internal
floors, etc.
Habitable room is a room used for dwelling
purposes but which is not solely a kitchen,
utility room, bathroom, cellar or sanitary
accommodation.
Infiltration is the uncontrolled exchange of air
between inside a building and outside through
cracks, porosity and other unintentional openings
in a building, caused by pressure difference
effects of the wind and/or stack effect.
Intermittent operation is where a mechanical
ventilator does not run all the time, usually running
only when there is a particular need to remove
pollutants or water vapour (e.g. during cooking
or bathing). Intermittent operation may be under
either manual control or automatic control.
Manual control is where a ventilation device is
opened and closed, or switched on and off, or its
performance is adjusted by the occupants of a
room or building (see automatic control).
Occupiable room is a room in a building other
than a dwelling that is occupied by people,
such as an office, workroom, classroom or
hotel bedroom, but not a bathroom, sanitary
accommodation, utility room or rooms or
spaces used solely or principally for circulation,
building services plant or storage purposes.
Passive stack ventilation (PSV) is a ventilation
system using ducts from terminals in the ceiling
of rooms to terminals on the roof that extract air
to outside by a combination of the natural stack
effect and the pressure effects of wind passing
over the roof of the building.
Permanent opening is a ventilation opening
which is permanently fixed in the open position.
Purge ventilation is manually controlled
ventilation of rooms or spaces at a relatively
high rate to rapidly dilute pollutants and/or water
vapour. Purge ventilation may be provided by
natural means (e.g. an openable window) or by
mechanical means (e.g. a fan).
Ventilation
8
Surface water activity is a measure of the
availability of water to micro-organisms, and is
determined from the ratio of the vapour pressure
of the water in the substrate to that of pure water
at the same temperature and pressure. This ratio
is, in steady-state conditions, numerically equal
to the equilibrium relative humidity of the air,
except that the latter is commonly expressed
as a percentage (from IEA Annex 14 source
book, 1991).
Utility room is a room containing a sink or other
feature or equipment which may reasonably be
expected to produce water vapour in significant
quantities.
Ventilation is the supply and removal of air (by
natural and/or mechanical means) to and from
a space or spaces in a building. It normally
comprises a combination of purpose-provided
ventilation and infiltration.
Ventilation opening is any means of purposeprovided ventilation (whether it is permanent
or closable) which opens directly to external air,
such as the openable parts of a window, a louvre
or a background ventilator. It also includes any
door which opens directly to external air.
Wet room is a room used for domestic activities
(such as cooking, clothes washing and bathing)
which give rise to significant production of
airborne moisture, e.g. a kitchen, utility room or
bathroom. For the purposes of Part F, sanitary
accommodation is also regarded as a wet room.
Whole building ventilation (general ventilation)
is nominally continuous ventilation of rooms
or spaces at a relatively low rate to dilute and
remove pollutants and water vapour not removed
by operation of extract ventilation, purge
ventilation or infiltration, as well as supplying
outdoor air into the building. For an individual
dwelling this is referred to as ‘whole dwelling
ventilation’.
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Types of work covered by this
Approved Document
3.2
This Approved Document gives guidance
on what, in ordinary circumstances, may be
considered reasonable provision for compliance
with the requirements of Part F of Schedule 1
to, and regulations 39, 42 and 44 (in so far as it
relates to fixed systems for mechanical ventilation)
of, the Building Regulations, and regulations 20(1)
and 20(6) (in so far as it relates to fixed systems
for mechanical ventilation) of the Approved
Inspectors Regulations, for those erecting new
dwellings and buildings other than dwellings, or
carrying out work on existing buildings.
Exemptions
3.3
The erection or extension of a number of
classes of buildings is exempt under regulation 9
of, and Schedule 2 to, the Building Regulations
from the requirements to comply with the
requirements in paragraph 3.2 above:
a. buildings controlled under the Manufacture
and Storage of Explosives Regulations 2005,
the Nuclear Installations Act 1965 or included
in the schedule of monuments maintained
under section 1 of the Ancient Monuments
and Archaeological Areas Act 1979;
b. detached buildings into which people do
not normally go, or go only intermittently
for the purpose of inspecting or maintaining
fixed plant or machinery, provided that the
buildings are a specified distance from
buildings into which people normally go;
c. greenhouses providing that the principal
purpose of the building is not retailing,
packing or exhibiting;
d. agricultural buildings (as defined), provided
that no part of the building is used as a
dwelling, that the building is at least one
and one-half times its height from a building
containing sleeping accommodation, and
that there is a fire exit not more than 30
metres distant from any point in the building.
Agricultural buildings used principally for
retailing, packing or exhibiting fall outside the
exemption;
e. temporary buildings not intended to remain in
place for more than 28 days;
f.
ancillary buildings used for the disposal
of buildings or building plots on site;
buildings on the site of construction or civil
engineering works for use only during the
course of those works and containing no
sleeping accommodation; and buildings on
the site of mines and quarries which do not
contain dwellings, nor are used as offices or
showrooms;
Approved Document F
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g. detached single-storey buildings, with less
than 30 m2 floor area and containing no
sleeping accommodation, which are either
constructed substantially of non-combustible
material or at least 1 metre from the boundary
of their curtilage;
h. detached buildings of less than 30 m2
floor area, designed and intended to be
used as shelters from nuclear, chemical or
conventional weapons and used for no other
purpose, provided the excavation for the
building is at least 1 metre plus the depth of
excavation from any other exposed structure;
i.
detached buildings of less than 15 m2 floor
area containing no sleeping accommodation;
and
j.
extensions of buildings at ground level with a
floor area less than 30 m2 by the addition of
a conservatory, porch, covered yard, covered
way, or carport open on at least two sides.
Notification of work covered by
the ventilation requirements
3.4
In most cases where it is proposed to
carry out notifiable ventilation work on a building
it will be necessary to notify the work to a BCB
in advance. This notification would usually be by
way of a full plans application or a building notice
given to a local authority, or an initial notice given
jointly with the approved inspector. However,
there are three circumstances where such work
need not be notified to a BCB in advance:
Competent person self-certification schemes
3.5
It is not necessary to notify a BCB in
advance of work which is to be carried out by
a person registered with a competent person
self-certification scheme for that type of work.
In order to join such a scheme a person must
demonstrate competence to carry out the type
of work the scheme covers, and also the ability
to comply with all relevant requirements in the
Building Regulations.
3.6
Where work is carried out by a person
registered with a competent person scheme,
regulation 20 of the Building Regulations and
regulation 20(1) of the Approved Inspectors
Regulations require that the occupier of
the building be given, within 30 days of the
completion of the work, a certificate confirming
that the work complies fully with all applicable
building regulation requirements. There is also a
requirement that the BCB be given a notice of
the work carried out, again within 30 days of the
completion of the work. These certificates and
notices are usually made available through the
scheme operator.
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3.7
BCBs are authorised to accept these
certificates and notices as evidence of
compliance with the requirements of the Building
Regulations. Local authority inspection and
enforcement powers remain unaffected, but
they are normally used only in response to a
complaint that work does not comply.
3.8
There are a number of competent person
schemes for the installation of mechanical
ventilation and air-conditioning systems in
buildings. A list of the schemes and the types of
work for which they are authorised is available at
www.communities.gov.uk.
Emergency repairs
3.9
Where the work involves an emergency
repair, e.g. to a failed fan, in accordance with
regulation 12(8) of the Building Regulations there
is no need to delay making the repair in order to
make an advance notification to the BCB where
this is not practicable. However, in such cases it
will still be necessary for the work to comply with
the relevant requirements and to give a notice
to the BCB at the earliest opportunity, unless
an installer registered under an appropriate
competent person scheme carries out the work.
A completion certificate can then be issued in the
normal way.
Minor works
3.10 Where the work is of a minor nature as
described in the schedule of non-notifiable
work (Schedule 4 to the Building Regulations),
the work must still comply with the relevant
requirements but need not be notified to the
BCB. In relation to mechanical ventilation and
air-conditioning systems such work includes:
•
replacement of parts, or the addition of an
output or control device where testing and
adjusting is not possible or would not affect
the system’s energy efficiency;
•
provision of a self-contained mechanical
ventilation or air-conditioning appliance
provided that any electrical work is exempt
from a requirement to give advance notice to
a BCB, and testing and adjustment is not
possible or would not affect its energy
efficiency, and the appliance is not installed in
a room containing an open-flued combustion
appliance. Examples might be a cooker hood,
a bathroom extract fan or a room airconditioning unit, which cannot be adjusted
from their factory settings.
VERSION
Historic and traditional buildings
3.11 As mentioned above in paragraph
3.3a, buildings included in the schedule of
monuments maintained under section 1 of the
Ancient Monuments and Archaeological Areas
Act 1979 are exempt from compliance with the
requirements of the Building Regulations. There
are other classes of buildings where special
considerations may apply in deciding what is
adequate provision for ventilation:
a. listed buildings;
b. buildings in conservation areas;
c. buildings which are of architectural and
historical interest and which are referred to as
a material consideration in a local authority’s
development plan or local development
framework;
d. buildings which are of architectural and
historical interest within national parks, areas
of outstanding natural beauty, registered
historic parks and gardens, registered
battlefields, the curtilages of scheduled
ancient monuments, and world heritage sites;
and
e. buildings of traditional construction with
permeable fabric that both absorbs and
readily allows the evaporation of moisture.
3.12 When undertaking work on or in
connection with a building that falls within one
of the classes listed above, the aim should
be to provide adequate ventilation as far as
is reasonable and practically possible. The
work should not prejudice the character of the
host building or increase the risk of long-term
deterioration of the building fabric or fittings.
3.13 The guidance given by English Heritage1
and in BS 7913 Principles of the conservation of
historic buildings should be taken into account in
determining appropriate ventilation strategies for
building work in historic buildings.
3.14 In general, new extensions to historic
or traditional dwellings should comply with
the standards of ventilation as set out in this
Approved Document. The only exception would
be where there is a particular need to match
the external appearance or character of the
extension to that of the host building.
3.15 Particular issues relating to work in historic
buildings that warrant sympathetic treatment
and where advice from others could therefore be
beneficial include:
a. restoring the historic character of a building
that has been subject to previous
inappropriate alteration, e.g. replacement
windows, doors and rooflights;
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b. rebuilding a former historic building (e.g.
following a fire or filling a gap site in a
terrace);
c. making provision for the fabric of historic
buildings to ‘breathe’ to control moisture and
potential long-term decay problems.
3.16 In determining what is adequate ventilation
in the circumstances, it is important that the
BCB takes into account the advice of the local
authority’s conservation officer. The views of the
conservation officer are particularly important
where building work requires planning permission
and/or listed building consent.
Material change of use
3.17 A change of use occurs when there
is a change in the purposes for which, or
circumstances in which, an existing building or
part of a building is used. For the purposes of
building regulations, a material change of use
occurs where, after the change:
Live-work units
3.19 If a unit contains both living
accommodation and space to be used for
commercial purposes (e.g. workshop or office),
the whole unit should be treated as a dwelling for
the purposes of this Approved Document as long
as the commercial part could revert to domestic
use. This could be the case if, for example:
a. there is direct access between the
commercial space and the living
accommodation; and
b. both are contained within the same thermal
envelope; and
c. the living accommodation occupies a
substantial proportion of the total area of the
unit.
Sub-paragraph c means that the presence
of (e.g.) a small manager’s flat in a large nondomestic building would not result in the
whole building being treated as a dwelling.
Similarly, the existence of a room used as an
office or utility space within a dwelling would
not mean that the building should not be
treated as a dwelling.
a. the building or part of a building is used as a
dwelling, where previously it was not;
b. the building or part of a building contains a
flat, where previously it did not;
c. the building or part of a building is used as a
hotel or a boarding house, where previously it
was not;
d. the building or part of a building is used as an
institution, where previously it was not;
e. the building or part of a building is used as a
public building, where previously it was not;
f.
the building or part of a building is not a
building described in Classes 1 to 4 in
Schedule 2, where previously it was;
g. the building or part of a building, which
contains at least one dwelling, contains a
greater or lesser number of dwellings than it
did previously;
h. the building or part of a building contains a
room for residential purposes, where
previously it did not;
i.
the building or part of a building, which
contains at least one room for residential
purposes, contains a greater or lesser
number of such rooms than it did previously;
or
j.
the building or part of a building is used as a
shop, where previously it was not.
3.18 Where a building undergoes any of the
material changes of use described above it
will be necessary for the resultant building to
comply with the requirements of Part F of the
Building Regulations. Where only part of the
building undergoes a material change of use,
normally only that part needs to comply with the
requirements of Part F.
Approved Document F
F1
Mixed use developments
3.20 When constructing a dwelling as part
of a larger building that contains other types
of accommodation, sometimes called a mixed
use development, Section 5 of this Approved
Document should be used for guidance in
relation to each individual dwelling. Section 6
gives guidance relating to the non-dwelling parts
of such buildings.
Materials and workmanship
3.21 Any building work which is subject to
the requirements imposed by Schedule 1 to the
Building Regulations should, in accordance with
regulation 7, be carried out with proper materials
and in a workmanlike manner.
3.22 You may show that you have complied
with regulation 7 in a number of ways. These
include demonstrating the appropriate use of:
•
a product bearing CE marking in accordance
with the Construction Products Directive
(89/106/EEC), as amended by the CE Marking
Directive (93/68/EEC), the Low Voltage
Directive (2006/95/EC) and the EMC Directive
(2004/108/EC); or
•
a product complying with an appropriate
technical specification (as defined in those
Directives mentioned above), a British
Standard, or an alternative national technical
specification of a Member State of the
European union or Turkey, or of another State
signatory to the Agreement on the European
Economic Area (EEA) that provides an
equivalent level of safety and protection; or
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a product covered by a national or European
certificate issued by a European Technical
Approval issuing body, provided the
conditions of use are in accordance with the
terms of the certificate.
3.23 You will find further guidance in the
Approved Document which specifically supports
regulation 7 on materials and workmanship.
Independent certification schemes
3.24 There are many uK product certification
schemes. Such schemes certify compliance with
the requirements of a recognised standard that is
appropriate to the purpose for which the material
is to be used. Materials which are not so certified
may still conform to a relevant standard.
3.25 Many certification bodies that approve
products under such schemes are accredited
by the united Kingdom Accreditation Service
(uKAS). Such bodies can issue certificates only
for the categories of product covered under the
terms of their accreditation.
3.26 BCBs may take account of the
certification of products, components, materials
or structures under such schemes in deciding
whether the relevant standard has been complied
with. Similarly, BCBs may take account of the
certification of the installation or maintenance of
products, components, materials or structures
under such schemes in deciding on compliance
with the relevant standard. Nonetheless,
before accepting that certification constitutes
compliance with building regulations, a BCB
should establish in advance that the relevant
scheme is adequate for that purpose.
VERSION
3.29 The appropriate use of a product in
compliance with a European Technical Approval
as defined in the Construction Products Directive
will meet the relevant requirements.
3.30 The Department intends to issue periodic
amendments to its Approved Documents
to reflect emerging harmonised European
standards. Where a national standard is to be
replaced by a European harmonised standard,
there will be a coexistence period during which
either standard may be referred to. At the end of
the coexistence period the national standard will
be withdrawn.
The Workplace (Health, Safety and
Welfare) Regulations 1992
3.31 The Workplace (Health, Safety and
Welfare) Regulations 1992, as amended, apply to
the common parts of flats and similar buildings if
people such as cleaners, wardens and caretakers
are employed to work in these common parts.
These Regulations contain some requirements
which affect building design. The main
requirements are now covered by the Building
Regulations, but for further information see
Workplace health, safety and welfare, Workplace
(Health, Safety and Welfare) Regulations 1992,
Approved Code of Practice and guidance, HSE
publication L24, 1996.
3.32 Where the requirements of the Building
Regulations that are covered by this Approved
Document do not apply to dwellings, the
provisions may still be required in the situations
described above in order to satisfy the Workplace
Regulations.
Standards and technical
specifications
3.27 Building regulations are made for specific
purposes, including securing the health, safety,
welfare and convenience of people in or about
buildings; furthering the conservation of fuel and
power; furthering the protection or enhancement
of the environment; and facilitating sustainable
development. Guidance contained in standards
and technical approvals is relevant to the extent
that it relates to those purposes. However, the
guidance may also address other aspects of
performance such as serviceability, or aspects
which, although they relate to health and safety,
are not covered by building regulations.
3.28 When an Approved Document makes
reference to a named standard or document, the
relevant version of the standard or document
is the one listed at the end of the Approved
Document. until the reference in the Approved
Document is revised, the standard or document
listed remains the approved source, but if the
issuing body has published a revised or updated
version, any content that addresses the relevant
requirements of the Building Regulations may be
used as a source of guidance.
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Section 4: Introduction to the provisions
Performance
The purpose of ventilation
4.1
The purpose of this section is to outline
briefly what ventilation in buildings is for and the
philosophy behind the guidance for ventilation
given in Approved Document F. More detail is
given in some of the informative Appendices at
the end of this Approved Document.
4.6
Ventilation is simply the removal of ‘stale’
indoor air from a building and its replacement
with ‘fresh’ outside air. It is assumed within the
Approved Document that the outside air is of
reasonable quality.
4.2
The key aim of the requirement of Part
F1(1) is that a ventilation system is provided that,
under normal conditions, is capable of limiting
the accumulation of moisture, which could lead
to mould growth, and pollutants originating within
a building which would otherwise become a
hazard to the health of the people in the building.
4.3
In general terms, the requirement may be
achieved by providing a ventilation system which:
a. extracts, before it is generally widespread,
water vapour from areas where it is produced
in significant quantities (e.g. kitchens, utility
rooms and bathrooms);
b. extracts, before they are generally
widespread, pollutants which are a hazard to
health from areas where they are produced in
significant quantities (e.g. rooms containing
processes or activities which generate
harmful contaminants);
c. rapidly dilutes, when necessary, pollutants
and water vapour produced in habitable
rooms, occupiable rooms and sanitary
accommodation;
d. makes available over long periods a minimum
supply of outdoor air for occupants and
disperses, where necessary, residual
pollutants and water vapour. Such ventilation
should minimise draughts and, where
necessary, should be reasonably secure and
provide protection against rain penetration;
e. is designed, installed and commissioned to
perform in a way which is not detrimental to
the health of the people in the building; and
f.
is installed to facilitate maintenance where
necessary.
4.4
The guidance in this Approved Document
has not been formulated to deal with the
products of tobacco smoking.
4.5
Ventilation systems in buildings result
in energy being used to heat fresh air taken
in from outside and, in mechanical ventilation
systems, to move air into, out of and/or around
the building. Energy efficiency is dealt with under
Part L of Schedule 1 and Regulation 40 of the
Building Regulations but consideration should
be given to mitigation of ventilation energy use,
where applicable, by employing heat recovery
devices, efficient types of fan motor and/or
energy-saving control devices in the ventilation
system.
Approved Document F
4.7
Ventilation is required for one or more of
the following purposes:
a. provision of outside air for breathing;
b. dilution and removal of airborne pollutants,
including odours;
c. control of excess humidity (arising from water
vapour in the indoor air);
d. provision of air for fuel-burning appliances
(which is covered under Part J of the Building
Regulations).
4.8
Ventilation may also provide a means to
control thermal comfort but this is not controlled
under the Building Regulations. Part L addresses
minimising energy use due to the effects of solar
gain in summer.
4.9
The airborne pollutants and water vapour
mentioned in paragraph 4.7b and c above
include those that are released from materials
and products paragraph used in the construction,
decoration and furnishing of a building, and as a
result of the activities of the building’s occupants.
4.10 The pollutant(s) of most importance will
vary between building types (e.g. dwelling, office,
factory), building uses (e.g. industrial process,
shop, commercial kitchen), and even from room
to room within a building (e.g. kitchen, shower
room, conference room, photocopier room).
Common pollutants in a dwelling are moisture
and combustion products from unflued appliances
(e.g. gas, oil or solid fuel cookers) and chemical
emissions from construction and consumer products.
Note that the ventilation system capacity, if used
appropriately, is usually sufficient to remove odours
arising from normal occupant activities within a
dwelling. In an office building, body odour is
often the key pollutant, but there are a number
of other pollutant sources including the building
itself, furnishings, printers and photocopiers.
Types of ventilation
4.11 Buildings are ventilated through a
combination of infiltration and purposeprovided ventilation:
•
Infiltration is the uncontrollable air exchange
between the inside and outside of a building
through a wide range of air leakage paths in
the building structure.
•
Purpose-provided ventilation is the
controllable air exchange between the inside
and outside of a building by means of a range
of natural and/or mechanical devices.
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4.12 It is important to minimise the
uncontrollable infiltration and supply sufficient
purpose-provided ventilation. Air tightness
measures to limit infiltration are covered in Part
L of the Building Regulations and its supporting
Approved Documents. Approved Document F
recommends methods of achieving sufficient
purpose-provided ventilation, allowing for a
reasonably high level of airtightness.
4.13 For the purposes of Part F, a reasonably
high level of airtightness means a level which
is significantly tighter than the minimum target
value recommended under Part L, because all
new buildings are expected to better the target
value to some degree. Through good design and
execution, domestic and non-domestic buildings
can currently achieve an air permeability down
to around 2 to 4 m3/(h.m2) of envelope area at 50
Pascal (Pa) pressure difference. Some buildings
constructed are tighter than this. It can be
anticipated that there will be a continual trend
towards more airtight buildings due to drivers
for higher energy efficiency and lower carbon
emissions.
4.14 The ventilation provisions recommended
for new dwellings in this Approved Document
have been specified for two standard designs of
air permeability:
•
•
In the default option, the guidance assumes
zero air permeability and thus no
infiltration. The building ventilation is reliant
entirely on installed purpose-provided
ventilation, thus ensuring sufficient
ventilation for dwellings of all levels of air
permeability. This option should be
particularly suitable when intending to
construct a more airtight dwelling, or where
the person carrying out the building work
does not have previous experience of closely
matching design with as-constructed air
permeability and may, as a consequence,
achieve a significantly better performance
than designed.
In the alternative option, the guidance
assumes an infiltration of 0.15 air changes
per hour (ach). The recommended purposeprovided ventilation is less as infiltration
contributes to the total amount of ventilation.
This option is most appropriate when
designing to an air permeability leakier than
5 m3/(h.m2) at 50 Pa, and it is expected from
experience that the measured air permeability
will be close to the design value and will not
be better than 3 m3/(h.m2) at 50 Pa.
Paragraphs 5.8 to 5.10 provide further
information.
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The ventilation strategy adopted in
Approved Document F
4.15 Approved Document F adopts the
following strategy. (Systems which comply with
the strategy are described in Sections 5 and 6.)
•
Extract ventilation from rooms where most
water vapour and/or pollutants are released,
e.g. due to activities such as cooking, bathing
or photocopying. This is to minimise their
spread to the rest of the building. This extract
may be either intermittent or continuous.
•
Whole building/dwelling ventilation to
provide fresh air to the building and to dilute
and disperse residual water vapour and
pollutants not dealt with by extract
ventilation as well as removing water vapour
and other pollutants which are released
throughout the building (e.g. by building
materials, furnishings, activities and the
presence of occupants). Whole building/
dwelling ventilation provides nominally
continuous air exchange. The ventilation rate
may be reduced or ceased when the building
is not occupied. It may be necessary to purge
the air when the building is re-occupied.
•
Purge ventilation throughout the building
to aid removal of high concentrations of
pollutants and water vapour released from
occasional activities such as painting and
decorating or accidental releases such as
smoke from burnt food or spillage of water.
Purge ventilation is intermittent, i.e. required
only when such occasional activities occur.
Purge ventilation provisions may also be
used to improve thermal comfort, although
this is not controlled under the Building
Regulations.
4.16 This ventilation strategy can be delivered
by a natural ventilation system or a mechanical
ventilation system or a combination of both (i.e.
‘mixed-mode’ or ‘hybrid’ ventilation system).
For mainly naturally ventilated buildings, it is
common to use a combination of ventilators
to achieve this strategy (e.g. for dwellings it is
common to use intermittent extract fans for
extract ventilation, trickle ventilators for whole
dwelling ventilation and windows for purge
ventilation). For mechanically ventilated or airconditioned buildings, it is common for the same
ventilators to provide both local extract and
whole building / dwelling ventilation and, for
buildings other than dwellings, to provide purge
ventilation as well.
4.17 The ventilation systems and devices
mentioned in this document are examples of
those commonly in use at the time of writing.
Other ventilation systems and devices, perhaps
following a different strategy (e.g. positive
input ventilation or supply air windows), may
provide acceptable solutions, provided it can
be demonstrated to the BCB (e.g. by use of
a product or system covered by a national or
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European certificate issued by a European
Technical Approval issuing body, provided
the conditions of use are in accordance with
the terms of the certificate) that they meet
Requirement F1. The assessment of the
suitability of a ventilation system should take
account of the design air permeability of the
building, and the fact that the completed building
may be ‘tighter’ than the design value because of
variability in construction quality.
Control of ventilation
4.18 It is important that ventilation is
controllable so that it can maintain reasonable
indoor air quality and avoid waste of energy.
These controls can be either manual
(i.e. operated by the occupant) or automatic.
Demand-controlled ventilation systems employ
sensors to detect the level of occupancy,
water vapour or other pollutants and adjust the
ventilation rate accordingly in order to avoid overventilation and so reduce energy consumption.
4.19 Manually controlled trickle ventilators (the
most common type of background ventilators)
can be located over the window frames, in
window frames, just above the glass or directly
through the wall (see Diagram 1 in Key terms).
They are positioned typically 1.7 m above floor
level to avoid discomfort due to cold draughts.
These ventilators often incorporate a simple
flap that allows users to shut off the ventilation
– depending on external weather conditions.
Trickle ventilators are intended to be normally left
open in occupied rooms in dwellings. A window
with a night latch position is not recommended
because of the difficulty of measuring the
equivalent area, the greater likelihood of
draughts and the potential increased security risk
in some locations.
4.20 In dwellings, humidity-controlled devices
are available to regulate the humidity of the
indoor air and, hence, minimise the risk of
condensation and mould growth. These are
best installed as part of an extract ventilator
in moisture-generating rooms (e.g. kitchen or
bathroom). Humidity control is not appropriate
for sanitary accommodation, where the
dominant pollutant is normally odour. Trickle
ventilators are available which ‘throttle down’
the ventilation flow passage(s) according to
the pressure difference across the ventilator
to reduce draught risks during windy weather.
Manufacturers should be consulted when
selecting the correct type of pressure-controlled
trickle ventilator.
4.21 Other types of automatic control may
be suitable for regulating ventilation devices
(e.g. trickle ventilators, ventilation fans, dampers
and air terminal devices) in dwellings. In such
cases, it is important that the device controls the
ventilation air supply and/or extract according to
the need for ventilation in the space to remove or
dilute indoor pollutants and water vapour. Trickle
ventilators with automatic controls should also
Approved Document F
F1
have manual override, so that the occupant can
close the ventilator to avoid draughts and fully
open the ventilator to provide maximum air flow
when required. For pressure-controlled trickle
ventilators that are fully open at typical conditions
(e.g. 1 Pa pressure difference), only a manual
close option is recommended.
4.22 In buildings other than dwellings, more
sophisticated automatic control systems are
available. These may be based on sensors
located within the building, e.g. occupancy
sensors (using local passive infra-red detectors)
or indoor carbon dioxide concentration sensors
(using electronic carbon dioxide detectors) as
an indicator of occupancy level and, therefore,
body odour.
Performance-based guidance
4.23 This Approved Document focuses on
performance-based guidance which suggests to
the designer what level of ventilation should be
sufficient, rather than how it should be achieved.
Therefore, the designer has the freedom to use
whatever ventilation provisions suit a particular
building, including the use of innovative products
and solutions, if it can be demonstrated that they
meet the performance standard recommended in
this Approved Document.
4.24 The actual performance criteria for
acceptable levels of moisture and pollutants are
given in Appendix A. The air flow rates necessary
to meet the performance criteria are given in the
main guidance.
4.25 Simple guidance in the form of ventilator
sizes for the whole dwelling is also provided to
make it easier for designers to meet building
regulations requirements in common situations.
Equivalent area of ventilators
4.26 Equivalent area is used in the Approved
Document instead of free area for the sizing
of background ventilators (including trickle
ventilators) because it is a better measure of
the air flow performance of a ventilator. unlike
equivalent area, free area is simply the physical
size of the aperture of the ventilator but may not
accurately reflect the air flow performance which
the ventilator will achieve. The more complicated
and/or contorted the air flow passages in a
ventilator, the less air will flow through it. So,
two different ventilators with the same free
area will not necessarily have the same air flow
performance. A European Standard, BS EN
13141-1:2004 (Clause 4), includes a method of
measuring the equivalent area of background
ventilator openings.
4.27 As equivalent area cannot be verified
with a ruler, it will be difficult to demonstrate to
Building Control Bodies that trickle ventilators
and similar products have the correct equivalent
area unless it is clearly marked on the product.
For this reason, it is preferable to use ventilators
which have the equivalent area (in mm² at
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1 Pa pressure difference), or equivalent area
per metre (where the equivalent area of the
product varies according to length) marked on
the product in an easily visible location from the
inside of the dwelling when installed. Where it
is not practical for the manufacturer to mark the
ventilator because it can be used in conjunction
with a range of other components, some form
of temporary marking for the installed system
should be acceptable to the BCB.
Ventilation effectiveness
4.28 Ventilation effectiveness is a measure of
how well a ventilation system works in terms of
delivering the supply air to the occupants of a
building. If the supply air is mixed fully with the
room air before it is breathed by the occupants,
the ventilation effectiveness is 1. If the supply
air is extracted from the room before it mixes
with any room air, the ventilation effectiveness
is 0. If the supply air reaches the occupant
without mixing with any room air, the ventilation
effectiveness tends towards infinity.
4.29 This is important as a system with
a higher ventilation effectiveness achieves
acceptable pollutant levels at the occupant’s
breathing zone for a lower air supply rate, and
offers potentially significant energy savings.
However, it has been decided not to make an
allowance for any reduction of fresh air supply
rates based on ventilation effectiveness in
Approved Document F at this time. This is
because ventilation effectiveness is dependent
on the ventilation system design, its installation
and the way in which occupants use the space.
While it is possible to predict what the ventilation
effectiveness of a system should be, there is
currently insufficient knowledge of the actual
ventilation effectiveness achieved in buildings to
allow designers to guarantee performance and
so avoid significant under-ventilation by reducing
air supply rates. This is because ventilation
effectiveness may be influenced by factors
beyond the designer’s control such as occupant
usage (e.g. seating plan and use of computers
within a space and whether the space is being
heated or cooled by the ventilation air). In the
designs shown in this Approved Document, it has
been assumed that the ventilation effectiveness
is 1.0. CIBSE Guide A provides further
information on ventilation effectiveness.
Source control
4.30 A complementary strategy for achieving
good indoor air quality is to reduce the release
of water vapour and/or air pollutants into the
indoor air, i.e. source control. Source control
is not considered within the main guidance
of the Approved Document owing to limited
knowledge about the emission of pollutants
from construction and consumer products
used in buildings and the lack of suitable
labelling schemes for England and Wales. Some
construction products such as glass, stone and
Ventilation
16
ceramics are by their nature low emitters of air
pollutants. Currently, some paints are labelled for
their volatile organic compound (VOC) content,
and some wood-based boards (class E1, BS EN
13986:2004) are available with low formaldehyde
emission. This allows suitable products to be
chosen when good indoor air quality is a priority,
but at the present time it is not practical to make
an allowance for use of these products in the
ventilation requirements. Further information
about control of emissions from construction
products is available in BRE Digest 464.
4.31 Exposure to house dust mite (HDM)
allergens can lead to allergic sensitisation and
to exacerbation of allergic conditions. The
moisture criteria needed to avoid HDM are more
complex and demanding than those needed
to avoid mould. The reduction of mite growth
may be feasible in uK dwellings via appropriate
ventilation, heating and moisture control as
part of an integrated approach that involves the
removal of existing mite allergens.
4.32 useful information may be found in the
World Health Organisation (WHO) publication,
House dust mites, Crowther D and Wilkinson
T (2008), which is included in Public health
significance of urban pests, Bonnefoy X,
Kampen H and Sweeney K, WHO Regional
Office for Europe, available at:
www.euro.who.int/document/e91435.pdf
4.33 Further information and suggested
measures for source control are given in Review
of health and safety risk drivers (BD 2518),
available at: www.communities.gov.uk/
publications/planningandbuilding/
reviewhealthsafety
Noise
4.34 The noise caused by ventilation systems
is not controlled under the Building Regulations.
However, such noise may be disturbing to the
occupants of a building and it is recommended
that measures be taken to minimise noise
disturbance. For example, in noisy areas, in order
to reduce noise entering the building through
the ventilation system, it may be appropriate
to use sound-attenuating ventilation products
depending on the noise level and any planning
conditions.
4.35 Noise from the ventilation system may also
disturb people who are outside the building, so
measures to minimise externally emitted noise
should also be considered.
4.36 Noise generated by ventilation fans (which
may travel through ducts) and noise from the fan
unit may disturb the occupants of the building
and so discourage their use. Therefore, the
designer should consider minimising noise by
careful design and the specification of quieter
products.
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To ensure good acoustic conditions, the average
A-weighted sound pressure level in noise
sensitive rooms, such as bedrooms and living
rooms, should not exceed 30 dB LAeq,T (see
Note below). In less sensitive rooms, such as
kitchens and bathrooms, a higher level would
be acceptable, e.g. 35 dB LAeq,T . Noise from
a continuously running mechanical ventilation
system on its minimum low rate should not
normally exceed these levels, and should
preferably be lower in order to minimise the
impact of the ventilation system.
The main issues to be addressed in minimising
the noise impact of the ventilation system are the
noise from the fan unit entering the ducts, and
the attenuation provided by the ducts, bends
and junctions and the characteristics of the room
grill. The noise breaking out of the fan unit casing
may also be significant in adjacent rooms. The
characteristics of the room will also affect the
noise level.
Methods for measuring the sound power level
produced by the fan unit of decentralised extract,
centralised extract, and balanced supply and
extract with heat recovery systems are under
development. When available, they should be
read in conjunction with the appropriate parts of
BS EN 13141.
Note:
The noise index LAeq,T is used in BS 8233:1999,
where T is the duration of the measurement. If
the noise from the sound source is steady (e.g.
fluctuating by up to 3 dB) a measuring time of
1 minute will be adequate and the LAeq,1 min level
will be similar to the dB(A) level used elsewhere.
If the noise from the sound source fluctuates
more than this a longer measuring time (T) will be
required.
Fire precautions
4.37 Where ducting passes through a fireresisting wall/floor or fire compartment, the
required measures to ensure compliance with
Part B of the Building Regulations must be taken.
Modular and portable buildings
4.38 Buildings constructed from subassemblies that are delivered newly made
or selected from stock should be treated no
differently from any other new building and must
comply with all the relevant requirements in
Schedule 1 to the Building Regulations 2010 that
were in force when they were manufactured. For
guidance on energy efficiency requirements, see
Approved Document L2A.
Approved Document F
F1
Installation of ventilation systems
4.39 It is recommended that ventilation systems
are installed in new and existing dwellings in
accordance with the guidance in the 2010 edition
of the Domestic ventilation compliance guide,
available from www.planningportal.gov.uk/
approveddocuments. The guide is referenced at
relevant points of this Approved Document – in
Section 5, New dwellings, and in Section 7, Work
on existing buildings.
4.40 Section 5 of the Domestic ventilation
compliance guide includes an installation
checklist which should be completed by the
system installer. It also includes an installation
inspection sheet where the equivalent area of
background ventilators should be recorded.
4.41 Installation guidance for buildings other
than dwellings can be found in the references
listed in Table 6.3.
Air flow rate testing and
commissioning of ventilation
systems
4.42
The Regulations require:
•
mechanical ventilation systems to be
commissioned (where they can be tested
and adjusted) to provide adequate ventilation
and a commissioning notice to be given to
the BCB;
•
air flow rates for mechanical ventilation
systems in new dwellings to be measured
and a notice to be given to the BCB.
4.43 For dwellings, the procedures approved
by the Secretary of State for measurement of air
flow rates and for commissioning of mechanical
ventilation systems are in Sections 2 and 3 of the
Domestic ventilation compliance guide. Section
5 of the guide contains air flow measurement
test and commissioning sheets which should
be completed by the person responsible for
commissioning.
4.44 For commissioning of non-domestic
ventilation systems, the commissioning
procedure approved by the Secretary of State is
CIBSE Code M, available from www.cibse.org.
4.45 The commissioning of mechanical
ventilation systems to provide adequate
ventilation under Part F of the Building
Regulations will need to be carried out with
the commissioning of such systems to ensure
that they use no more fuel and power than is
reasonable in the circumstances under Part L of
the Building Regulations. It is permissible for the
notice of commissioning to be given to the BCB
to cover the commissioning required under both
Parts F and L. Approved Documents L1A, L1B,
L2A and L2B give guidance on commissioning
required by Part L.
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4.46 In addition, guidance on commissioning
ventilation ductwork is provided in the HVCA
guidance documents DW/144 Specification
for sheet metal ductwork: low, medium and
high pressure/velocity air systems, DW/154
Specification for plastics ductwork, and DW/143
Practical guide to ductwork leakage testing, all
available from www.hvca.org.uk.
Provision of information
4.47 The Regulations require sufficient
information about the ventilation system and its
maintenance requirements to be given to owners
so that the ventilation system can be operated to
provide adequate air flow.
4.48 For new and existing dwellings, Section 4
of the Domestic ventilation compliance guide lists
the documents that it is recommended should
be given to the dwelling owner at installation
handover. The inspection checklist and air flow
measurement test and commissioning sheet in
Section 5 should form part of the information
pack. The parts of Section 5 covering air flow
measurement and commissioning should also be
given to the BCB.
4.49 For new and existing buildings other
than dwellings, a way of showing compliance
would be to follow the guidance in Approved
Documents L2A and L2B, which reference the
CIBSE TM 31 Building log book toolkit, 2006.
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Approved Document F
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Section 5: New dwellings
Introduction to provisions
5.3
Note that extract fans lower the pressure
in a building, which can cause the spillage of
combustion products from open-flued appliances
(i.e. the combustion gases may fill the room
instead of going up the flue or chimney). This
can occur even if the appliance and the fan are
in different rooms. Ceiling sweep fans produce
air currents and hence local depressurisation,
which can also cause the spillage of flue gases
from open-flued gas appliances or from solid
fuel open fires. In buildings where it is intended
to install open-flued combustion appliances and
extract fans, the combustion appliance should
be able to operate safely whether or not the
fans are running. A way of showing compliance
in these circumstances would be to follow the
guidance given in Approved Document J on both
the installation of the appliances and tests to
show that combustion appliances operate safely
whether or not fans are running.
5.1
This Approved Document shows three
main ways of complying with the ventilation
requirements of the Building Regulations:
a. providing the ventilation rates set out in
paragraphs 5.4 to 5.7; or
b. following the system guidance set out:
for dwellings without basements in
paragraphs 5.8 to 5.10. This guidance
covers all levels of design air permeability.
Alternative guidance is also provided for
dwellings designed to an air permeability
leakier than (>) 5 m3/(h.m2) at 50 Pa where the
developer from experience will not construct
significantly more airtight dwellings (not better
than 3 m3/(h.m2) at 50 Pa); or
for dwellings with basements in paragraphs
5.11 to 5.13; or
c. using other ventilation systems provided it
can be demonstrated to the Building Control
Body that they satisfy the Requirement, e.g.
by showing that they meet the moisture and
air quality criteria set out in Appendix A.
5.2
There should be reasonable access for
maintenance. This should include access
for the purpose of changing filters, replacing
defective components and cleaning ductwork.
Table 5.1a Extract ventilation rates
Room
Intermittent extract
Continuous extract
Minimum rate
Minimum
high rate
Kitchen
30 l/s adjacent to hob; or
60 l/s elsewhere
13 l/s
utility room
30 l/s
8 l/s
Bathroom
15 l/s
8 l/s
Sanitary accommodation
6 l/s
6 l/s
Minimum
low rate
Total extract rate should be
at least the whole dwelling
ventilation rate given in Table
5.1b
Table 5.1b Whole dwelling ventilation rates
Number of bedrooms in dwelling
Whole dwelling ventilation
rate a, b (l/s)
1
2
3
4
5
13
17
21
25
29
Notes:
a. In addition, the minimum ventilation rate should be not less than 0.3 l/s per m2 of internal floor area. (This includes all floors, e.g. for a two-storey
building add the ground and first floor areas.)
b. This is based on two occupants in the main bedroom and a single occupant in all other bedrooms. This should be used as the default value. If a
greater level of occupancy is expected add 4 l/s per occupant.
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Ventilation rates
5.4
The performance will be achieved by
providing the air flow rates set out in paragraphs
5.5 to 5.7. The air flow rates specified are for
the performance of the complete installation.
The performance of the ventilation devices (and
associated components such as ducting for fans)
should be tested according to the Standards
listed under ‘Performance test methods’ in Table
5.3. All natural and mechanical systems should
be fully commissioned, and guidance is given
in the Domestic ventilation compliance guide,
available from: www.planningportal.gov.uk/
approveddocuments.
VERSION
5.10 In addition to this guidance, for each
system alternative guidance is provided for
dwellings with as-built air permeabilities leakier
than (>) 3 m3/(h.m2) at 50 Pa. It is recommended
that this option is selected only if designing to
an air permeability leakier than (>) 5 m3/(h.m2)
at 50 Pa and if the person carrying out the
building work has previous experience of closely
matching design with as-built air permeability
levels. If the alternative guidance is followed, and
it is subsequently found that either
•
the tested air permeability for that dwelling
is tighter than or equal to (≤) 3 m3/(h.m2) at
50 Pa, or
5.5
Extract ventilation to outside is required
in each kitchen, utility room and bathroom and
for sanitary accommodation. The extract can
be either intermittent or continuously operating.
The intermittent rate, and for continuous systems
the minimum extract air flow rates at the highest
and lowest settings, should be no less than
specified in Table 5.1a.
•
if the dwelling is not tested, but another
dwelling of the same dwelling type tested
under regulation 43 is tighter than or equal to
(≤) 3 m3/(h.m2) at 50 Pa,
5.6
The whole dwelling ventilation rate for
the supply of air to the habitable rooms in a
dwelling should be no less than specified in Table
5.1b.
Step 1: Select one of the following four
ventilation systems (illustrated in Diagram 2a).
5.7
Purge ventilation provision is required
in each habitable room and should be capable
of extracting a minimum of four air changes
per hour (ach) per room directly to outside.
Normally, openable windows or doors can
provide this function (see Appendix B), otherwise
a mechanical extract system should be provided.
In other rooms (e.g. kitchens and bathrooms) the
mechanical or passive stack extract provisions
should be sufficient, although passive stack
ventilation will take longer to purge the room.
Ventilation systems for dwellings
without basements
5.8
The performance required for dwellings
without basements could be achieved by
following Steps 1 and 2 below. Worked examples
for each system are given in Appendix C.
5.9
For each system, guidance is given for
dwellings to cover all design air permeabilities.
This guidance is therefore suitable for all
dwellings and, for ventilation purposes, it is not
necessary for the as-built permeability to be
close to the design permeability.
Ventilation
20
it may be necessary for the BCB to ask for more
air permeability testing to be carried out to
ensure all dwellings in the sample are provided
with adequate ventilation.
System 1: Background ventilators and
intermittent extract fans. Guidance
on minimum provisions for extract and
whole dwelling ventilation is set out in Table
5.2a. Note that it includes separate guidance
for dwellings with habitable rooms having
only a single exposed façade.
System 2: Passive stack ventilation (PSV).
Guidance on minimum provisions for extract
and whole dwelling ventilation is set out in
Table 5.2b.
System 3: Continuous mechanical extract
(MEV). Guidance on minimum provisions for
extract and whole dwelling ventilation is
set out in Table 5.2c.
System 4: Continuous mechanical supply
and extract with heat recovery (MVHR).
Guidance on minimum provisions for extract
and whole dwelling ventilation is set out in
Table 5.2d.
Step 2: See Table 5.3 for guidance on
performance test methods for the products
chosen.
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Diagram 2a Ventilation systems
Passive stack ventilation
Stack ducts
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Diagram 2b Single-sided ventilation
Table 5.2a System 1 – Background ventilators and intermittent extract fans
(for additional information see Table 5.3 and worked examples C1 and
C5 in Appendix C)
Design of system 1
The background ventilators have been sized for the winter period. Additional ventilation may be required during warmer months and
it has been assumed that the provisions for purge ventilation (e.g. openable windows) could be used.
Intermittent extract
• Intermittent extract rates are given in Table 5.1a. For sanitary accommodation only, as an alternative, the purge ventilation
provisions (windows) given in Appendix B can be used where security is not an issue.
• Instead of a conventional intermittent fan, a continuously running single room heat recovery ventilator could be used in wet
rooms. It should use the minimum high rate given in Table 5.1a and 50% of this value as the minimum low rate. No background
ventilator is required in the same room as the single room heat recovery ventilator. Furthermore, the total equivalent background
ventilator area described in the tables below can be reduced by 2500 mm2 for each room containing a single room heat recovery
ventilator.
Location of intermittent extract fans
• Intermittent extract fans should be installed in each wet room.
• Cooker hoods should be 650 mm to 750 mm above the hob surface (or follow manufacturer instructions).
• Intermittent extract fans other than cooker hoods should be installed as high as is practical and preferably less than 400 mm
below the ceiling.
• Where fans and background ventilators are fitted in the same room they should be a minimum of 0.5 m apart.
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Table 5.2a System 1 – Background ventilators and intermittent extract fans
(for additional information see Table 5.3 and worked examples C1 and
C5 in Appendix C)
Background ventilators (follow Steps 1 to 3 below)
Step 1: Determine the total equivalent ventilator area – See Table A below for a dwelling with any design air permeability. As an
alternative, the guidance in Table B below may be followed for a dwelling designed to an air permeability leakier than (>) 5 m3/(h.m2)
at 50 Pa which recommends less ventilation provisions, but see the cautionary advice in paragraph 5.10.
Step 2: Follow (i) or (ii) as appropriate depending on the number of storeys:
(i) For multi-storey dwellings, and single-storey dwellings more than four storeys above ground level:
• use the total equivalent ventilator area from Step 1.
(ii) For single-storey dwellings up to and including the fourth storey above ground level:
• Add a further 10000 mm2 to the total equivalent ventilator area from Step 1, preferably shared between several rooms.
Step 3: For dwellings which have a single exposed façade, or at least 70% of the equivalent area is designed to be on the
same façade, cross-ventilation is not possible, or is limited, and additional ventilation provisions are recommended. In this case
background ventilators should be located at both high and low positions in the façade to provide enhanced single-sided ventilation.
The total equivalent area as described in Steps 1 and 2 above should be provided at the high position (typically 1.7 m above floor
level) for all dwelling types and all storey heights. In addition, ventilators having the same total equivalent area should be provided at
least 1.0 m below the high ventilators as shown in Diagram 2b. Single-sided ventilation is most effective if the dwelling is designed so
that the habitable rooms are on the exposed façade, and these rooms are no greater than 6 m in depth.
A – Total equivalent ventilator area a (mm2) for a dwelling with any design air permeability.
Total floor area (m2)
Number of bedrooms b
1
2
3
4
5
≤50
35000
40000
50000
60000
65000
51–60
35000
40000
50000
60000
65000
61–70
45000
45000
50000
60000
65000
71–80
50000
50000
50000
60000
65000
81–90
55000
60000
60000
60000
65000
91–100
65000
65000
65000
65000
> 100
65000
Add 7000 mm for every additional 10 m floor area
2
2
B – Alternative guidance on total equivalent ventilator area a (mm2) for a dwelling with a designed air permeability leakier than
(>) 5 m3/(h.m2) at 50 Pa.
Total floor area (m2)
Number of bedrooms b
1
2
3
4
5
≤50
25000
35000
45000
45000
55000
51–60
25000
30000
40000
45000
55000
61–70
30000
30000
30000
45000
55000
71–80
35000
35000
35000
45000
55000
81–90
40000
40000
40000
45000
55000
91–100
45000
45000
45000
55000
> 100
45000
Add 5000 mm for every additional 10 m floor area
2
2
Notes:
a. The equivalent area of a background ventilator should be determined at 1 Pa pressure difference, using the appropriate test method given in Table
5.3.
b. This is based on two occupants in the main bedroom and a single occupant in all other bedrooms. For a greater level of occupancy, assume a
greater number of bedrooms (i.e. assume an extra bedroom per additional person). For more than five bedrooms, add an additional 10000 mm2 per
bedroom.
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Table 5.2a System 1 – Background ventilators and intermittent extract fans
(for additional information see Table 5.3 and worked examples C1 and
C5 in Appendix C)
Location of background ventilators
• Background ventilators should be located to avoid draughts, e.g. typically 1.7 m above floor level (except in the single-sided
case described above).
• Background ventilators should be located in all rooms with external walls, with at least 5000 mm2 equivalent area in each
habitable room and 2500 mm2 equivalent area in each wet room. If a habitable room has no external walls follow the guidance
in paragraphs 5.14 to 5.16. If a wet room has no external walls follow the guidance for intermittent extract given for Purge
ventilation and Controls below.
• If the dwelling has more than one exposed façade, to maximise the air flow through the dwelling by encouraging cross-ventilation,
it is best to locate similar equivalent areas of background ventilators on opposite (or adjacent) sides of the dwelling.
Purge ventilation
For each habitable room with:
• external walls, see Appendix B for window or external door (including patio door) sizing;
• no external walls, see paragraphs 5.14 to 5.16.
There may be practical difficulties in achieving this (e.g. if unable to open a window due to excessive noise from outside).
For each wet room with:
• external walls, install an openable window (no minimum size);
• no external walls, the normal extract provisions will suffice, although it will take longer to purge the room.
As an alternative to the provisions given above for habitable and wet rooms, a mechanical fan extracting at 4 ach to outside could
be used.
Devices used for purge ventilation should be manually controlled. The location of the devices is not critical for ventilation.
Air transfer
• To ensure good transfer of air throughout the dwelling, there should be an undercut of minimum area 7600 mm2 in all internal
doors above the floor finish. This is equivalent to an undercut of 10 mm for a standard 760 mm width door. This should be
achieved by making an undercut of 10 mm above the floor finish if the floor finish is fitted, or by a 20 mm undercut above the
floorboards, or other surface, if the finish has not been fitted.
Controls
Intermittent extract
• May be operated manually and/or automatically by a sensor (e.g. humidity, occupancy/usage, pollutant release). Humidity controls
should not be used for sanitary accommodation as odour is the main pollutant.
• In kitchens, any automatic control must provide sufficient flow during cooking with fossil fuel (e.g. gas) to avoid build-up of
combustion products.
• Any automatic control should have a manual override to allow the occupant to turn the extract on.
• In a room with no openable window (i.e. an internal room) an intermittent extract fan should have a 15 minute overrun. In rooms
with no natural light, the fans could be controlled by the operation of the main room light switch.
Background ventilators
• May be either manually adjustable or automatically controlled (see paragraphs 4.18 to 4.20).
Manual controls
Where manual controls are provided, they should be within reasonable reach of the occupants. It is recommended that they are
located in accordance with the guidance for Requirement N3 Safe opening and closing of windows etc., which is given in Approved
Document N. Where reasonable, pull cords, operating rods or similar devices should be provided. Although Requirement N3 applies
only to workplaces, for the purpose of this Approved Document it should also apply to dwellings.
Noise
Fans should be quiet so as not to discourage their use by occupants.
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Table 5.2b System 2 – Passive stack ventilation (PSV) (for additional information
see Table 5.3 and worked examples C2 and C6 in Appendix C)
Design of system 2
The background ventilators have been sized for the winter period. Additional ventilation may be required during warmer months and
it has been assumed that the provisions for purge ventilation (e.g. openable windows) could be used.
Ceiling extract grilles should have a free area of not less than the duct cross-sectional area (when in the fully open position if
adjustable).
If a dwelling in which PSV is proposed is situated near a significantly taller building (i.e. more than 50% taller), it should be at least
five times the difference in height away from the taller building (e.g. if the difference in height is 10 m, PSV should not be installed in a
dwelling within 50 m of the taller building).
The roof terminal design should be as specified by the PSV manufacturer.
Size of passive stack ventilators
Room
Internal duct diameter (mm)
Internal cross-sectional area (mm2)
Kitchen
125
12000
utility room
125
12000
Bathroom
125
12000
Sanitary accommodation*
125
12000
*For sanitary accommodation only, as an alternative, the purge ventilation provisions (windows/doors) given in Appendix B can be
used where security is not an issue.
Location of PSV
• For a dwelling with only a single exposed façade, the dwelling should be designed such that the habitable rooms are on the
exposed façade so as to achieve cross-ventilation.
• PSV extract terminals should be located in the ceiling or on a wall less than 400 mm below the ceiling.
Instead of PSV, an open-flued appliance may provide sufficient extract ventilation for the room in which it is located when in
operation, and can be arranged to provide sufficient ventilation when not firing. For instance, the provisions would be adequate if: (a)
the solid fuel open-flued appliance is a primary source of heating, cooking or hot water production; or (b) the open-flued appliance
has a flue of free area at least equivalent to a 125 mm diameter duct and the appliance’s combustion air inlet and dilution inlet are
permanently open, i.e. there is a path with no control dampers which could block the flow, or the ventilation path can be left open
when the appliance is not in use (see also paragraph 5.3).
Background ventilators (follow Steps 1 to 3 below)
Step 1: Determine the total equivalent ventilator area – See Table A below for a dwelling with any design air permeability. As an
alternative, the guidance in Table B below may be followed for a dwelling with a designed air permeability leakier than (>) 5 m3/(h.m2)
at 50 Pa which recommends less ventilation provisions, but see the cautionary advice in paragraph 5.10.
Step 2: Make an allowance for the total air flow through all PSV units. As an approximation assume each PSV unit provides an
equivalent area of 3000 mm2.
Step 3: The actual equivalent ventilator area required for the dwelling is the value found in Steps 1 and 2.
In addition to this, the total equivalent area of the background ventilators must be at least equal to the total cross-sectional area of
all the PSV ducts.
A – Total equivalent ventilator area a (mm2) for a dwelling with any design air permeability.
Total floor area (m2)
Number of bedrooms b
1
2
3
4
5
≤50
35000
40000
50000
60000
65000
51–60
35000
40000
50000
60000
65000
61–70
45000
45000
50000
60000
65000
71–80
50000
50000
50000
60000
65000
81–90
55000
60000
60000
60000
65000
91–100
65000
65000
65000
65000
65000
> 100
Approved Document F
Add 7000 mm2 for every additional 10 m2 floor area
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Table 5.2b System 2 – Passive stack ventilation (PSV) (for additional information
see Table 5.3 and worked examples C2 and C6 in Appendix C)
B – Alternative guidance on total equivalent ventilator area a (mm2) for a dwelling with a designed air permeability leakier than
(>) 5 m3/(h.m2) @ 50 Pa.
Total floor area (m2)
Number of bedrooms b
1
2
3
4
5
≤50
25000
35000
45000
45000
55000
51–60
25000
30000
40000
45000
55000
61–70
30000
30000
30000
45000
55000
71–80
35000
35000
35000
45000
55000
81–90
40000
40000
40000
45000
55000
91–100
45000
45000
45000
45000
55000
> 100
Add 5000 mm2 for every additional 10 m2 floor area
Notes:
a. The equivalent area of a background ventilator should be determined at 1 Pa pressure difference, using the appropriate test method given in Table
5.3.
b. This is based on two occupants in the main bedroom and a single occupant in all other bedrooms. For a greater level of occupancy, assume a
greater number of bedrooms (i.e. assume an extra bedroom per additional person). For more than five bedrooms, add an additional 10000 mm2 per
bedroom.
Location of background ventilators
• Background ventilators should be located in all rooms with external walls except the rooms where a PSV is located, but openflued combustion appliances will still require an air supply as given in Approved Document J. There should be at least 5000 mm2
equivalent area in each habitable room and 2500 mm2 equivalent area in each wet room not containing a PSV.
• If a habitable room has no external walls, follow the guidance in paragraphs 5.14 to 5.16.
• Background ventilators should be located to avoid draughts, e.g. typically 1.7 m above floor level.
• If the dwelling has more than one exposed façade, to maximise the air flow through the dwelling by encouraging cross ventilation,
it is best to locate similar equivalent areas of background ventilators on opposite (or adjacent) sides of the dwelling.
Purge ventilation
For each habitable room with:
• external walls, see Appendix B for window or external door (including patio door) sizing;
• no external walls, see paragraphs 5.14 to 5.16.
There may be practical difficulties in achieving this (e.g. if unable to open a window due to excessive noise from outside).
For each wet room with:
• external walls, install an openable window (no minimum size);
• no external walls – the PSV systems will be adequate, although it may take longer to purge the room.
As an alternative to the provisions given above for habitable and wet rooms, a mechanical fan extracting at 4 ach to outside could
be used.
Devices used for purge ventilation should be manually controlled. The location of the devices is not critical for ventilation.
Air transfer
• To ensure good transfer of air throughout the dwelling, there should be an undercut of minimum area 7600 mm2 in all internal
doors above the floor finish. This is equivalent to an undercut of 10 mm for a standard 760 mm width door. This should be
achieved by making an undercut of 10 mm above the floor finish if the floor finish is fitted, or by a 20 mm undercut above the
floorboards, or other surface, if the finish has not been fitted.
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Table 5.2b System 2 – Passive stack ventilation (PSV) (for additional information
see Table 5.3 and worked examples C2 and C6 in Appendix C)
Controls
• Should be set up to operate without occupant intervention. May have automatic controls (e.g. sensors for humidity, occupancy/
usage, pollutant release). Humidity controls should not be used for sanitary accommodation as odour is the main pollutant.
• In kitchens, any automatic control must provide sufficient flow during cooking with fossil fuel (e.g. gas) to avoid build-up of
combustion products.
• Ensure that the system always provides the minimum whole dwelling ventilation rate specified in Table 5.1b in the heating season.
Background ventilators
• May be either manually adjustable or automatically controlled (see paragraphs 4.18 to 4.20).
Manual controls
Where manual controls are provided, they should be within reasonable reach of the occupants. It is recommended that they are
located in accordance with the guidance for Requirement N3 Safe opening and closing of windows etc., which is given in Approved
Document N. Where reasonable, pull cords, operating rods or similar devices should be provided. Although Requirement N3 applies
only to workplaces, for the purpose of this Approved Document it should also apply to dwellings.
Table 5.2c System 3 – Continuous mechanical extract (MEV) (for additional
information see Table 5.3 and worked examples C3 and C7 in Appendix C)
Design of continuous mechanical extract systems
System 3 has been sized for the winter period. Additional ventilation may be required during warmer months and it has been
assumed that the provisions for purge ventilation (e.g. openable windows) could be used.
Step 1: Determine the whole dwelling ventilation rate from Table 5.1b.
(Note: no allowance is made for infiltration as the extract system lowers the pressure in the dwelling and all air flow through
infiltration paths does not increase the overall ventilation rate.)
Step 2: Calculate the whole dwelling extract ventilation rate by summing the individual room rates for ‘minimum high rate’ from Table 5.1a.
(For sanitary accommodation only, as an alternative, the purge ventilation provisions given in Appendix B can be used where
security is not an issue. In this case the ‘minimum high extract rate’ for the sanitary accommodation should be omitted from the
Step 2 calculation.)
Step 3: The required extract rates are as follows:
The maximum whole dwelling extract ventilation rate (i.e. the boost rate) should be at least the greater of Step 1 and Step 2. Note
that the maximum individual room extract rates should be at least those given in Table 5.1a for minimum high rate.
The minimum whole dwelling extract ventilation rate should be at least the whole dwelling ventilation rate found in Step 1.
Note: This system could comprise either a central extract system or individual room fans (or a combination of both). To ensure that
the system provides the intended ventilation rate, measures should be taken to minimise likely wind effects when any extract terminal
is located on the prevailing windward façade. Possible solutions include ducting to another façade, use of constant volume flow rate
units or, for central extract systems, follow more detailed guidance which has been prepared by the Energy Saving Trust (EST) and
the Building Research Establishment (BRE) in conjunction with The Electric Heating and Ventilation Association (TEHVA) and the
Residential Ventilation Association (RVA). This guidance, entitled Performance testing of products for residential ventilation should be
read in conjunction with the appropriate parts of BS EN 13141 and is available at the SAP Appendix q website www.sap-appendixq.
org.uk/page.jsp?id=5
Note: if a single room heat recovery ventilator (SRHRV) is used to ventilate a habitable room, with ventilation of the rest of the
dwelling provided by continuous mechanical extract, the air flow rates are determined as follows:
• determine the whole dwelling ventilation rate from Table 5.1b;
• calculate the room supply rate required for the SRHRV from: (Whole dwelling ventilation rate × Room volume)/(Total volume of all
habitable rooms);
undertake Steps 1 to 3 above for sizing the continuous mechanical extract for the rest of the dwelling. However, when performing
Step 1, the supply rate specified for the SRHRV should be subtracted from the value given in Table 5.1b.
Background ventilators
For any design air permeability, controllable background ventilators having a minimum equivalent area of 2500 mm2 should be
fitted in each room, except wet rooms, from which air is extracted. As an alternative, where the designed air permeability is leakier
than (>) 5 m3/(h.m2) at 50 Pa background ventilators are not necessary, but see the cautionary advice in paragraph 5.10. Where this
approach causes difficulties (e.g. on a noisy site) seek expert advice.
Where background ventilators are fitted:
• they should be located to avoid draughts, e.g. typically 1.7 m above floor level;
• fans and background ventilators fitted in the same room should be a minimum of 0.5 m apart;
• background ventilators may be either manually adjustable or automatically controlled (see paragraphs 4.18 to 4.20).
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Table 5.2c System 3 – Continuous mechanical extract (MEV) (for additional
information see Table 5.3 and worked examples C3 and C7 in Appendix C)
Purge ventilation
For each habitable room with:
• external walls, see Appendix B for window or external door (including patio door) sizing;
• no external walls, see paragraphs 5.14 to 5.16.
There may be practical difficulties in achieving this (e.g. if unable to open a window due to excessive noise from outside). In such
situations, seek expert advice.
For each wet room with:
• external walls, install an openable window (no minimum size);
• no external walls, the normal extract provisions will suffice, although it will take longer to purge the room.
As an alternative to the provisions given above for habitable and wet rooms, a mechanical fan extracting at 4 ach to outside could be used.
Devices used for purge ventilation should be manually controlled. The location of the devices is not critical for purge ventilation.
Location of ventilation devices
• Extract should be from each wet room.
• Cooker hoods should be 650 mm to 750 mm above the hob surface (or follow manufacturer instructions).
• Mechanical extract terminals and fans should be installed as high as is practicable and preferably less than 400 mm below the ceiling.
• Where ducts etc. are provided in a dwelling with a protected stairway, precautions may be necessary to avoid the possibility of
the system allowing smoke or fire to spread into the stairway. See Approved Document B.
Air transfer
• To ensure good transfer of air throughout the dwelling, there should be an undercut of minimum area 7600 mm2 in all internal
doors above the floor finish. This is equivalent to an undercut of 10 mm for a standard 760 mm width door. This should be
achieved by making an undercut of 10 mm above the floor finish if the floor finish is fitted, or by a 20 mm undercut above the
floorboards, or other surface, if the finish has not been fitted.
Controls
• Should be set up to operate without occupant intervention, but may have manual or automatic controls to select the boost rate.
Any manual boost controls should be provided locally to the spaces being served, e.g. bathrooms and kitchen, as provision
of a single centrally located switch may result in fans being left in an inappropriate mode of operation. Automatic controls
could include sensors for humidity, occupancy/usage and pollutant release. Humidity controls should not be used for sanitary
accommodation as odour is the main pollutant.
• In kitchens, any automatic control must provide sufficient flow during cooking with fossil fuel (e.g. gas) to avoid build-up of
combustion products.
• Ensure that the system always provides the minimum whole dwelling ventilation rate specified in Table 5.1b.
Where manual controls are provided, they should be within reasonable reach of the occupants. It is recommended that they are
located in accordance with the guidance for Requirement N3 Safe opening and closing of windows etc., which is given in Approved
Document N. Where reasonable, pull cords, operating rods or similar devices should be provided. Although Requirement N3 applies
only to workplaces, for the purpose of this Approved Document it should also apply to dwellings.
Noise
Any continuously running fans should be quiet so as not to discourage their use by occupants. Guidance on noise is given in
paragraphs 4.35 to 4.39.
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Table 5.2d System 4 – Continuous mechanical supply and extract with heat
recovery (MVHR) (for additional information see Table 5.3 and worked
examples C4 and C8 in Appendix C)
Design of MVHR systems
System 4 has been sized for the winter period. Additional ventilation may be required during warmer months and it has been
assumed that the provisions for purge ventilation (e.g. openable windows) could be used.
Step 1: For any design air permeability, determine the whole dwelling ventilation supply rate from Table 5.1b.
As an alternative where the designed air permeability is intended to be leakier than (>) 5 m3/(h.m2) at 50 Pa, allow for infiltration for
all dwelling types by subtracting from the whole dwelling ventilation supply rate from Table 5.1b: 0.04 l/(s.m3) x gross internal
volume of the dwelling heated space (m3), but see the cautionary advice in 5.10.
Step 2: Calculate the whole dwelling extract ventilation rate by summing the individual room rates for ‘minimum high rate’ from
Table 5.1a.
(For sanitary accommodation only, as an alternative, the purge ventilation provisions given in Appendix B can be used where
security is not an issue. In this case the ‘minimum high extract rate’ for sanitary accommodation should be omitted from the Step 2
calculation.)
Step 3: The required air flow rates are as follows:
• The maximum whole dwelling extract ventilation rate (i.e. the boost rate) should be at least the greater of Step 1 and Step 2. Note
that the maximum individual room extract rates should be at least those given in Table 5.1a for ‘minimum high rate’.
• The minimum whole dwelling supply ventilation rate should be at least the whole dwelling ventilation rate found in Step 1.
Purge ventilation
For each habitable room:
• with external walls, see Appendix B for window or external door (including patio door) sizing;
• without external walls, see paragraphs 5.14 to 5.16.
There may be practical difficulties in achieving this (e.g. if unable to open a window due to excessive noise from outside). In such
situations, seek expert advice.
For each wet room:
• with external walls, install an openable window (no minimum size);
• without external walls, the normal extract provisions will suffice, although it will take longer to purge the room.
As an alternative to the provisions given above for habitable and wet rooms, a mechanical fan extracting at 4 ach to outside could
be used.
Devices used for purge ventilation should be manually controlled. The location of the purge devices is not critical for ventilation.
Location of ventilation devices
• Extract should be from each wet room. Air should normally be supplied to each habitable room. The total supply air flow should
usually be distributed in proportion to the habitable room volumes. Recirculation by the system of moist air from the wet rooms
to the habitable rooms should be avoided.
• Cooker hoods should be 650 mm to 750 mm above the hob surface (or follow the manufacturer’s instructions).
• Mechanical extract terminals and fans should be installed as high as is practical and preferably less than 400 mm below the
ceiling.
• Mechanical supply terminals should be located and directed to avoid draughts.
• Where ducts etc. are provided in a dwelling with a protected stairway, precautions may be necessary to avoid the possibility of
the system allowing smoke or fire to spread into the stairway. See Approved Document B.
• Background ventilators are not required with System 4.
Air transfer
• To ensure good transfer of air throughout the dwelling, there should be an undercut of minimum area 7600 mm2 in all internal
doors above the floor finish. This is equivalent to an undercut of 10 mm for a standard 760 mm width door. This should be
achieved by making an undercut of 10 mm above the floor finish if the floor finish is fitted, or by a 20 mm undercut above the
floorboards, or other surface, if the finish has not been fitted.
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Table 5.2d System 4 – Continuous mechanical supply and extract with heat
recovery (MVHR) (for additional information see Table 5.3 and worked
examples C4 and C8 in Appendix C)
Controls
• Should be set up to operate without occupant intervention, but may have manual or automatic controls to select the boost rate.
Any manual boost controls should be provided locally to the spaces being served, e.g. bathrooms and kitchen, as provision
of a single centrally located switch may result in fans being left in an inappropriate mode of operation. Automatic controls
could include sensors for humidity, occupancy/usage and pollutant release. Humidity controls should not be used for sanitary
accommodation as odour is the main pollutant.
• In kitchens, any automatic control must provide sufficient flow during cooking with fossil fuel (e.g. gas) to avoid build-up of
combustion products.
• Ensure the system always provides the minimum whole dwelling ventilation rate specified in Table 5.1b.
Where manual controls are provided, they should be within reasonable reach of the occupants. It is recommended that they are
located in accordance with the guidance for Requirement N3 Safe opening and closing of windows etc., which is given in Approved
Document N. Where reasonable, pull cords, operating rods or similar devices should be provided. Although Requirement N3 applies
only to workplaces, for the purpose of this Approved Document it should also apply to dwellings.
Noise
All continuously running fans used should be quiet so as not to discourage their use by occupants. Guidance on noise is given in
paragraphs 4.34 to 4.36.
Table 5.3 Performance test methods
The minimum performance requirements specified within Tables 5.2a to 5.2d should be measured using the test methods contained
in relevant clauses of the following documents.
Intermittent extract fans
• BS EN 13141-4 clause 4 Performance testing of aerodynamic characteristics. All sub-clauses are relevant.
Range hoods
• BS EN 13141-3 clause 4 Performance testing of aerodynamic characteristics. All sub-clauses are relevant.
Background ventilators (non-RH controlled)
• BS EN 13141-1 clause 4 Performance testing of aerodynamic characteristics. Only the following sub-clauses are relevant:
a. 4.1 Flow rate/pressure; and
b. 4.2 Non-reverse flow ability.
The performance requirements should normally be met for both air flow from outside to inside the dwelling and for inside to outside.
To ensure that the installed performance of background ventilators is similar to the results achieved when they are tested to this
Standard, background ventilators and associated components should be installed according to manufacturers’ instructions. This
also applies to non-RH controlled sound-attenuating background ventilators.
Passive stack ventilators
For the commissioning of passive stack systems follow the guidance in the Domestic ventilation compliance guide, available from:
www.planningportal.gov.uk/approveddocuments.
Continuous mechanical extract (MEV) systems
BS EN 13141-6 clause 4 Performance testing of aerodynamic characteristics. Also see Note 2 below.
Continuous supply and extract ventilation MVHR units
BS EN 13141-7 clause 6 Test methods. Also see Note 2 below.
Single room heat recovery ventilators
BS EN 13141-8 clause 6 Test methods. Only the following sub-clauses are relevant:
6.1 General; and
6.2 Performance testing of aerodynamic characteristics sub-clauses 6.2.1 Leakage and mixing and 6.2.2 Air flow.
For internal and external leakage and for mixing, the unit should meet at least Class u4 as given in clause 3.2 Classification.
Note 1. For all ventilation devices (e.g. extract fan, cooker hood), fitting ducting, intake/exhaust terminals, filters, etc. will impose an
additional resistance to the air flow. Where appropriate this should be allowed for when specifying ventilation system components
because, for example, a fan that meets the appropriate requirements when tested on its own may fail to meet the requirement when
it is installed and fitted with ducting etc. In such cases, the performance of the separate components should be measured according
to the relevant parts of BS EN 13141 and other relevant standards. The complete assembly, as installed, should be designed to meet
the performance requirement by following good practice such as is given in the Domestic ventilation compliance guide, available
from: www.planningportal.gov.uk/approveddocuments.
Note 2. Detailed guidance on the tests to be undertaken has been prepared by the Energy Saving Trust (EST) and the Building Research
Establishment (BRE) in conjunction with The Electric Heating and Ventilation Association (TEHVA) and the Residential Ventilation
Association (RVA). This guidance, entitled Performance testing of products for residential ventilation, should be read in conjunction with
the appropriate parts of BS EN 13141 and is available at the SAP Appendix q website: www.sap-appendixq.org.uk/page.jsp?id=5
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Ventilation systems for basements
5.11 For a dwelling which includes a basement
that is connected to the rest of the dwelling
above ground by a large permanent opening
(e.g. an open stairway), the whole dwelling
including the basement should be ventilated in
accordance with paragraph 5.8 (for dwellings
without basements) and treated as a multistorey dwelling. If the basement has only a
single exposed façade, while the rest of the
dwelling above ground has more than one
exposed façade, ventilation systems 3 and 4 are
preferred, following the guidance in paragraph
5.8. If systems 1 or 2 are to be used, seek expert
advice.
5.12 For a dwelling which includes a basement
that is not connected to the rest of the dwelling
above ground by a large permanent opening:
a. the part of the dwelling above ground should
be considered separately and ventilated in
accordance with paragraph 5.8. If the part of
the dwelling above ground has no bedrooms,
assume it has one bedroom for the purpose
of determining ventilation provisions; and
b. the basement should be treated separately
as a single-storey dwelling above ground
level in accordance with paragraph 5.8. If the
basement has no bedrooms, assume it has
one bedroom for the purpose of determining
ventilation provisions. The guidance on
natural ventilation given in the Approved
Document may not be appropriate for this
situation and expert advice should
be sought.
5.13 A dwelling which comprises only a
basement should be treated as a single-storey
dwelling above ground level in accordance
with paragraph 5.8. The guidance on natural
ventilation given in the Approved Document may
not be appropriate for this situation and expert
advice should be sought.
Ventilation of a habitable room
through another room or a
conservatory
F1
5.15 A habitable room not containing openable
windows may be ventilated through another
habitable room (see Diagram 3) if:
a. there is, from the habitable rooms to
outside, provision for both:
i.
purge ventilation, one or more
ventilation openings, with a total area
given in Diagram 3 based on at least the
combined floor area of the habitable
rooms; and
ii. background ventilation of at least 8000
mm2 equivalent area; and
b. there is an area of permanent opening
between the two rooms as given in Diagram 3
based on at least the combined floor area of
the habitable rooms.
5.16 A habitable room not containing
openable windows may be ventilated through a
conservatory (see Diagram 4) if:
a. there is, from the conservatory to outside,
provision for both:
i.
purge ventilation, one or more
ventilation openings, with a total area
given in Diagram 4 based on at least the
combined floor area of the habitable
room and conservatory; and
ii. background ventilation, a ventilation
opening (or openings) of at least 8000
mm2 equivalent area; and
b. there are openings (which must be closable)
between the habitable room and the
conservatory for:
i.
purge ventilation equivalent to
paragraph 5.15a(i) above; and
ii. background ventilation equivalent to
paragraph 5.15a(ii) above which should
be located typically at least 1.7 m above
floor level and need not be within the
door frame.
5.14 In a habitable room not containing
openable windows (i.e. an internal room) the
requirement will be met if the room is ventilated
either through another habitable room (see
paragraph 5.15) or through a conservatory (see
paragraph 5.16).
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Diagram 3 Two habitable rooms treated as a single room for ventilation purposes
Diagram 4 A habitable room ventilated through a conservatory
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Approved Document F
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Section 6: New buildings other than dwellings
General
6.1
This Approved Document sets out
guidance for the following range of building types
and uses:
a. offices – paragraphs 6.9 to 6.17;
Ventilation hygiene toolkit and HVCA TR/19 –
Guide to good practice – Internal cleanliness of
ventilation systems.
Diagram 4 Spaces for access
b. car parks – paragraphs 6.19 to 6.22;
c. other building types – paragraph 6.18.
6.2
The ventilation provisions will not
necessarily meet cooling needs. Guidance
on limiting solar gains in summer to control
overheating is considered in Approved Document
L2A Conservation of fuel and power in new
buildings other than dwellings.
6.3
Provision should be made to protect the
fresh air supplies from contaminants injurious
to health. Guidance on the siting of air inlets is
provided in Appendix D.
6.4
Guidance on design measures to
avoid legionella contamination, including
design features not related to the ventilation
of the building, is given in the HSE document
Legionnaires’ disease: the control of legionella
bacteria in water systems (see paragraphs 79 to
144). Further guidance may be found in CIBSE
TM13 Minimising the risk of Legionnaires’ disease
and in BSRIA Application Guides AG19/2000,
AG20/2000 and AG21/2000.
6.5
Guidance on recirculated air in airconditioning and mechanical ventilation systems
is given in HSE document L24 Workplace health,
safety and welfare, Workplace (Health, Safety and
Welfare) Regulations 1992, Approved Code of
Practice and guidance (paragraph 32).
Access for maintenance
6.6
Reasonable provision would be to include:
a. access for the purpose of replacing filters,
fans and coils; and
b. provision of access points for cleaning duct
work.
6.7
In a central plant room adequate space
should be provided as necessary for the
maintenance of the plant. Where no special
provision is required, the requirement could be
satisfied if 600 mm space is provided where
access is required between plant and 1100 mm
where space for routine cleaning is required
(see Diagram 5). These figures are the minimum
necessary and additional space may be needed
for opening of access doors, withdrawal of
filters, etc. Further guidance for more complex
situations can be found in Defence Works
Functional Standard, Design & Maintenance
Guide 08: Space requirements for plant access
operation and maintenance. Further guidance
for the cleaning of ducts is provided by CIBSE
Approved Document F
Offices
Introduction to provisions
6.8
This Approved Document shows four ways
of complying with the ventilation requirements of
the Building Regulations:
a. providing a ventilation system which meets
the air flow rates set out in paragraphs 6.9
to 6.13; or
b. following the system guidance set out in
paragraphs 6.14 and 6.15; or
c. using the alternative approaches set out in
paragraph 6.16; or
d. using other ventilation systems, provided it
can be demonstrated to the Building Control
Body that they satisfy the Requirement, e.g.
by showing that they meet the moisture and
air quality criteria set out in Appendix A.
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Table 6.1a Extract ventilation rates
Room
Extract rate
Rooms containing printers and photocopiers in
substantial use (greater than 30 minutes
per hour)
Air extract rate of 20 l/s per machine during use. Note that, if the operators are
in the room continuously, use the greater of the extract and whole building
ventilation rates
Office sanitary accommodation and washrooms
Intermittent air extract rate of:
15 l/s per shower/bath
6 l/s per WC/urinal
Food and beverage preparation areas (not
commercial kitchens)
Intermittent air extract rate of:
15 l/s with microwave and beverages only
30 l/s adjacent to the hob with cooker(s)
60 l/s elsewhere with cooker(s)
All to operate while food and beverage preparation is in progress
Specialist buildings/spaces (e.g. commercial
kitchens, sports centres)
See Table 6.3
Table 6.1b Whole building ventilation rate for air supply to offices
Air supply rate
Total outdoor air supply rate for offices (no smoking and no significant pollutant sources)
10 l/s per person
Table 6.2a Ventilation for offices with natural air supply – ventilation provisions
Extract
Extract rates as per paragraph 6.10(1, 2)
Whole building ventilation
See CIBSE Application Manual AM 10: Natural ventilation in non-domestic buildings.
Purge ventilation
See CIBSE Application Manual AM 10: Natural ventilation in non-domestic buildings.
Notes:
1. PSV can be used as an alternative to a mechanical extract fan for office sanitary, washroom and food preparation areas.
2. When an open-flued appliance is provided in a building with mechanical extract, the spillage of flue gases could occur. The openflued appliance needs to operate safely whether or not the fan is running, and further guidance is provided in BS 5440-1 which
applies for up to 70 kW appliance input.
Table 6.2b Ventilation for offices with natural air supply – location of
ventilators in rooms
Extract
• Extract ventilators should be located as high as practicable and preferably less than 400 mm below the ceiling. This will tend to
remove pollutants from the breathing zone of the occupants as well as increase the effectiveness of extracting buoyant pollutants
and water vapour.
• For PSV, extract terminals should be located in the ceiling of the room.
Whole building ventilation
• See CIBSE Application Manual AM 10: Natural ventilation in non-domestic buildings.
Purge ventilation
• See CIBSE Application Manual AM 10: Natural ventilation in non-domestic buildings.
Ventilation
34
ONLINE VERSION
Approved Document F
O N LTHAN
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NEW BuILDINGS OTHER
F1
Ventilation rates
Mechanical ventilation of rooms
6.9
The performance will be achieved by
ventilation which provides the air flow rates set
out in paragraphs 6.10 to 6.13. The air flow rates
specified are for the installed performance.
6.15 The requirement will be satisfied by
following:
6.10 Extract to outside is required in all office
sanitary accommodation, washrooms and food
and beverage preparation areas. In addition,
printers and photocopiers in substantial use
(greater than 30 minutes per hour) should be
located in a separate room (to avoid any pollutants
entering the occupied space) and extract provision
installed. The extract flow rates should be no less
than those specified in Table 6.1a.
6.11 The whole building ventilation rate for
the supply of air to the offices should be no less
than that specified in Table 6.1b.
6.12 Purge ventilation provision is required
in each office. The total ventilation should be
sufficient to reduce pollutants to an acceptable
level before the space is occupied. The purged
air should be taken directly to outside and should
not be re-circulated to any other part of the
building.
6.13 The outdoor air supply rates in Table 6.1b
for offices are based on controlling body odours
with low levels of other pollutants. Where there
are significant levels of other pollutants, adequate
outdoor air supply can be achieved by following
the calculation method provided in CIBSE
Guide A.
Natural ventilation of rooms
•
the air flow rates set out in paragraphs 6.9 to
6.13; and
•
the location guidance in Table 6.2b for
extract ventilation; and
•
the control guidance in Table 6.2c for extract
ventilation.
Alternative approaches
6.16 As an alternative to paragraphs 6.9 to 6.13
the requirement will be satisfied by following the
relevant recommendations of:
a. CIBSE Application Manual AM 13: 2000:
Mixed mode ventilation;
b. CIBSE Guide A and CIBSE Guide B.
Ventilation of other types of
building
6.17 The requirement will be satisfied by
following the appropriate design guidance for
the other buildings given in Table 6.3. In addition
to the guidance documents listed, it should be
noted that the Workplace (Health, Safety and
Welfare) Regulations 1992 apply to most places
where people work. A short guide, INDG244, is
available from the HSE and at: www.hse.gov.uk/
pubns/indg244.pdf.
6.14 The air flow rates specified in Tables 6.1a
and 6.1b can be provided by a mainly natural
ventilation system by following the guidance
in Tables 6.2a, 6.2b and 6.2c. A wide range
of natural ventilation systems for providing
whole building ventilation is given in CIBSE
Application Manual AM 10: Natural ventilation in
non-domestic buildings.
Table 6.2c Ventilation for offices with natural air supply – controls for ventilators
in rooms
Extract
• Extract fans can be controlled either manually or automatically. For a room with no openable window (i.e. an internal room), the
extract should have a 15 minute overrun.
• For PSV, either operated manually and/or automatically by a sensor or controller.
Whole building ventilation
• See CIBSE Application Manual AM 10: Natural ventilation in non-domestic buildings.
Purge ventilation
• See CIBSE Application Manual AM 10: Natural ventilation in non-domestic buildings.
Accessible controls
• Readily accessible override controls should be provided for the occupants.
Approved Document F
ONLINE VERSION
Ventilation
35
F1
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ILDINGS
DWELLINGS
Table 6.3: Ventilation of other buildings and spaces
Building/space/activity
Regulations and guidance (also see Section 8)
Animal husbandry
The Welfare of Farm Animals (England) Regulations SI 2000 No. 1870 London: The
Stationery Office 2000.
The Welfare of Farm Animals (England) (Amendment) Regulations SI 2002 No.1646
The Welfare of Farm Animals (England) (Amendment) Regulations SI 2003 No. 299
BS 5502:2003 Buildings and Structures for Agriculture
See also CIBSE Guide B:2005, Section 2.3.24.1, and CIBSE AM10:2005 if
naturally ventilated
Assembly halls
CIBSE Guide B:2005, Section 2.3.3, and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Atria
CIBSE Guide B:2005, Section 2.3.4, and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Broadcasting studios
CIBSE Guide B:2005, Section 2.3.5
Building services plant rooms
Provision for emergency ventilation to control dispersal of contaminating gas
releases (e.g. refrigerant leak) is given in paragraphs 23 to 25 of HSE Guidance
Note 202 General Ventilation in the Workplace – Guidance for Employers. Other
guidance is in BS 4434:1989 Specification for safety aspects in the design,
construction and installation of refrigeration appliances and systems
Call centres
CIBSE Guide B:2005, Section 2.3.24.2 and CIBSE AM10:2005 if naturally
ventilated or CIBSE AM13:2000 if mixed mode
Catering (inc. commercial kitchens)
HSE Catering Information Sheet No. 10, 2000: Ventilation of kitchens in catering
establishments
HSE Information Sheet No. 11, 2000: The main health and safety law applicable to
catering
See also CIBSE Guide B:2005, Section 2.3.6, and HVCA DW /172 Specification
for kitchen ventilation systems
Cleanrooms
CIBSE Guide B:2005, Section 2.3.7
Common spaces
The following provisions apply to common spaces where large numbers of
people are expected to gather, such as shopping malls and foyers. They do not
apply to common spaces used solely or principally for circulation.
Either:
a. natural ventilation by appropriately located ventilation opening(s) with a total
opening area of at least 1/50th of the floor area of the common space; or
b. mechanical ventilation installed to provide a supply of fresh air of 1 l/s per m2 of
floor area
Communal residential buildings
EST, Energy Efficiency Best Practice in Housing, Good Practice Guide GPG 192:
Designing energy efficient multi-residential buildings
See also CIBSE Guide B:2005, Section 2.3.8, and CIBSE AM10:2005 if naturally
ventilated or CIBSE AM13:2000 if mixed mode
Computer rooms
CIBSE Guide B:2005, Section 2.3.9, and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Darkrooms (photographic)
CIBSE Guide B:2005, Section 2.3.24.4
Dealing rooms
CIBSE Guide B:2005, Section 2.3.24.5 and CIBSE AM10:2005 if naturally
ventilated or CIBSE AM13:2000 if mixed mode
Factories and warehouses
Factories Act
Health and Safety at Work etc. Act
See also CIBSE Guide B:2005, Section 2.3.11, and CIBSE AM10:2005 if
naturally ventilated or CIBSE AM13:2000 if mixed mode. Requirements are often
exceeded by other criteria such as the ventilation requirements of the particular
manufacturing process
High-rise (non-domestic buildings)
CIBSE Guide B:2005, Section 2.3.12, and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Horticulture
CIBSE Guide B:2005, Section 2.3.24.6, and CIBSE AM10:2005 if naturally
ventilated or CIBSE AM13:2000 if mixed mode
Ventilation
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Approved Document F
O N LTHAN
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VERSION
NEW BuILDINGS OTHER
F1
Table 6.3: Ventilation of other buildings and spaces
Building/space/activity
Regulations and guidance (also see Section 8)
Hospitals and healthcare buildings
NHS Activity database
Health Technical Memorandum (HTM) 03
Health Building Notes (HBN) – various
CIBSE Guide B:2005, Section 2.3.13, and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Hotels
CIBSE Guide B:2005, Section 2.3.14, and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Industrial ventilation
Industrial ventilation, 24th Edition, Manual of recommended practice, American
Conference of Government Industrial Hygienists
HS(G) 37 An introduction to local exhaust ventilation
HS(G) 54 Maintenance, examination and testing of local exhaust ventilation
HS(G) 193 COSHH essentials
Laboratories
CIBSE Guide B:2005, Section 2.3.16
Museums, libraries and art galleries
BS 5454:2000
CIBSE Guide B:2005, Section 2.3.17, and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Plant rooms
CIBSE Guide B:2005, Section 2.3.18
Prison cells
Refer to National Offender Management Service (NOMS). Home Office, NOMS
Property, Technical Services, Room 401, Abell House, John Islip St., London
SW1P 4LH
Sanitary accommodation
Same as for offices in Table 6.1a
Schools and educational buildings
Ventilation provisions in schools can be made in accordance with the guidance in
Building Bulletin 101, Ventilation of School Buildings (see www.teachernet.gov.uk/
iaq) and in the Education (School Premises) Regulations. Building Bulletin 101 can
also be used as a guide to the ventilation required in other educational buildings
such as further education establishments where the accommodation is similar to
that found in schools, e.g. sixth form accommodation. However, the standards
may not be appropriate for particular areas where more hazardous activities take
place than are normally found in schools, e.g. some practical and vocational
activities requiring containment or fume extraction.
The Building Bulletin can also be used for children’s centres and other early years
settings, including day nurseries, playgroups, etc.
Shops and retail premises
CIBSE Guide B:2005, Section 2.3.20, and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Sports centres (inc. swimming pools)
CIBSE Guide B:2005, Section 2.3.21
Standards rooms
CIBSE Guide B:2005, Section 2.3.24.7
Transportation buildings and facilities
CIBSE Guide B:2005, Section 2.3.23 and CIBSE AM10:2005 if naturally ventilated
or CIBSE AM13:2000 if mixed mode
Approved Document F
ONLINE VERSION
Ventilation
37
O OTHER
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ILDINGS
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F1
Ventilation of car parks
6.18 The requirement will be satisfied for car
parks below ground level, for enclosed-type car
parks and for multi-storey car parks if the mean
predicted pollutant levels are calculated, the
ventilation rate is designed and equipment is
installed to limit the carbon monoxide to:
a. an average concentration of not more than
30 parts per million over an eight hour
period; and
b. peak concentrations, such as by ramps and
exits, of not more than 90 parts per million for
periods not exceeding 15 minutes.
6.19 Note that Approved Document B also
includes provisions for the ventilation of car parks
for the purpose of fire risk management.
Alternative approaches for
ventilation of car parks
6.20 As an alternative to paragraph 6.18, the
following guidance would satisfy the requirement:
a. Naturally ventilated car parks. The provision
of well-distributed permanent natural
ventilation, e.g. openings at each car parking
level with an aggregate equivalent area
equal to at least 1/20th of the floor area at
that level, of which at least 25% should be on
each of two opposing walls.
b. Mechanically ventilated car parks
i.
either the provision of both permanent
natural ventilation openings of
equivalent area not less than 1/40th of
the floor area and a mechanical ventilation
system capable of at least three air
changes per hour (ach); or
for basement car parks, the provision of a
mechanical ventilation system capable of
at least six air changes per hour (ach).
And:
ii. for exits and ramps, where cars queue
inside the building with engines running,
provisions should be made to ensure
a local ventilation rate of at least 10 air
changes per hour (ach).
6.21 Further guidance can be found in Code
of practice for ground floor, multi-storey and
underground car parks published by the
Association for Petroleum and Explosives
Administration (www.apea.org.uk); CIBSE Guide
B:2005, Section 2.3.23.3; and Health and Safety
Publication EH40: Occupational exposure limits
for limiting concentration of exhaust pollutants.
Fire safety issues are considered in Approved
Document B.
Ventilation
38
ONLINE VERSION
Approved Document F
ONLINE VERSION
F1
Section 7: Work on existing buildings
General
Buildings other than dwellings:
7.1
When building work is carried out on an
existing building, the work should comply with
the applicable requirements of Schedule 1 to
the Building Regulations, and the rest of the
building should not be made less satisfactory in
relation to the requirements than before the work
was carried out (see regulations 3 and 4 of the
Building Regulations). Further, when a building
undergoes a material change of use, as defined
in regulation 5 of the Building Regulations (see
paragraph 3.17 above), Part F applies to the
building or that part of the building which has
been subject to the change of use, in accordance
with regulation 6. Therefore, the guidance in
other sections of this Approved Document may
be applicable.
•
occupiable rooms: for floor areas up to
10 m2 – 2500 mm2 equivalent area; greater
than 10 m2 – at the rate of 250 mm2
equivalent area per m2 of floor area
•
kitchens (domestic type) – 2500 mm2
equivalent area
•
bathrooms and shower rooms – 2500 mm2
equivalent area per bath or shower
•
sanitary accommodation (and/or washing
facilities) – 2500 mm2 equivalent area
per WC.
7.2
Windows are a controlled fitting.
Regulation 4(1) of the Building Regulations
requires that, when windows in an existing
building are replaced, the replacement work
should comply with the applicable requirements
of Schedule 1, i.e. Parts L and N. In addition, the
building work once completed should not have a
worse level of compliance with other applicable
requirements of Schedule 1 than before
commencement of the work. Other applicable
requirements of Schedule 1 may include Parts B,
F and J.
7.3
Where the original windows were fitted
with trickle ventilators the replacement windows
should include them and they should be sized as
set out in paragraph 7.6.
7.4
Where the original windows were not
fitted with trickle ventilators and the room is
not ventilated adequately by other installed
provisions, it would be good practice to fit trickle
ventilators (or an equivalent means of ventilation)
to help with control of condensation and improve
indoor air quality. Ventilation devices should be
fitted with accessible controls.
See A guide to trickle ventilators at
www.ggf.org.uk
7.5
When windows are replaced as part of the
work connected with a material change of use,
Sections 5 and 6 of this Approved Document apply.
7.6
In all cases where trickle ventilators (or
an equivalent means of ventilation) are to be
fitted, the new ventilation opening should not
be smaller than was originally provided, and
it should be controllable. Where there was no
ventilation opening, or where the size of the
original ventilation opening is not known, the
following minimum sizes should be adopted.
Dwellings:
•
habitable rooms – 5000 mm2 equivalent area
•
kitchen, utility room and bathroom (with or
without WC) – 2500 mm2 equivalent area.
Approved Document F
Addition of a habitable room (not
including a conservatory) to an
existing dwelling
7.7
The requirements will be met by following
the guidance in paragraphs 7.8 to 7.10.
7.8
The general ventilation rate for the
additional room and, if necessary, adjoining
rooms could be achieved by one of the following
options.
a. Background ventilators could be used as
follows:
i.
if the additional room is connected to
an existing habitable room which now
has no windows opening to outside, the
guidance in paragraph 5.15 should be
followed; or
ii. if the additional room is connected to an
existing habitable room which still has
windows opening to outside but with a
total background ventilator equivalent
area less than 5000 mm2, the guidance in
paragraph 5.15 should be followed; or
iii. if the additional room is connected to an
existing habitable room which still has
windows opening to outside and with a
total background ventilator equivalent
area of at least 5000 mm2, there should
be background ventilators of at least
8000 mm2 equivalent area between the
two rooms and background ventilators
of at least 8000 mm2 equivalent area
between the additional room and outside.
b. A single room heat recovery ventilator could
be used to ventilate the additional habitable
room. The supply rate to that room should be
determined as follows. First, determine the
whole building ventilation rate from Table
5.1b. Second, calculate the room supply rate
required from:
(Whole building ventilation rate × Room volume)
(Total volume of all habitable rooms)
7.9
For purge ventilation, follow the guidance
given in Table 5.2a.
ONLINE VERSION
Ventilation
39
F1
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WORK ON EXISTING
B
BuILDINGS
uILDINGS
7.10 Guidance on location and controls is also
given in Table 5.2a and guidance on performance
testing standards is given in Table 5.3.
Refurbishing a kitchen or
bathroom in an existing dwelling
Addition of a wet room to an
existing dwelling
7.21 If any of the work being carried out in the
kitchen or bathroom of an existing building is
‘building work’, as defined in regulation 3 of the
Building Regulations, the Regulations require that
you comply with the appropriate requirements
of the Regulations, and in doing so you do not
make compliance with other requirements of
the Regulations, including ventilation, worse
than before. The Regulations also require that
before you start work, the work is notified to
a BCB, except in certain circumstances. (See
paragraphs 3.4 to 3.10 inclusive above for details
of notification requirements and exemptions.)
7.11 The requirements for the additional wet
room will be met by following the guidance in
paragraphs 7.12 to 7.15.
7.12 Whole building and extract ventilation
can be provided by:
a. intermittent extract, as given in Table 5.2a,
and a background ventilator of at least
2500 mm2 equivalent area; or
b. single room heat recovery ventilator, as given
in Table 5.2a; or
c. passive stack ventilator, as given in Table
5.2b; or
d. continuous extract fan, as given in Table 5.2c.
7.13 To ensure good transfer of air throughout
the dwelling, there should be an undercut of
minimum area 7600 mm2 in the internal door
between the wet room and the existing dwelling.
This is equivalent to an undercut of 10 mm for
a standard 760 mm width door. This should be
achieved by making an undercut of 10 mm above
the floor finish if the floor finish is fitted, or by a
20 mm undercut above the floorboards, or other
surface, if the finish has not been fitted.
7.14 For purge ventilation, follow the guidance
for the appropriate system given in Tables 5.2a
to 5.2c.
7.15 Guidance on location and controls is
given in Tables 5.2a to 5.2c and guidance on
performance standards is given in Table 5.3.
7.22 The definition of ‘building work’ in
regulation 3 of the Building Regulations includes
a range of building activities in existing buildings,
and includes all work on controlled services.
For more information see the Building Regulations
2010 at: www.planningportal.gov.uk.
7.23 If you carry out any ‘building work’, and
there is an existing extract fan or passive stack
ventilator (or cooker hood extracting to outside
in the kitchen), you should retain or replace it.
However, if there is no existing ventilation system
you need not provide one. Replacing an extract
fan or cooker hood with a similar type, and using
the existing cabling, need not be notified to
a BCB.
7.24 If a combustion appliance is installed,
Approved Document J: Combustion appliances
and fuel storage systems should be consulted.
It is available at:
www.planningportal.gov.uk/approveddocuments.
Addition of a conservatory to an
existing building
7.16 The guidance applies to conservatories
with a floor area over 30 m2.
7.17 The requirements will be met by following
the guidance in paragraphs 7.18 to 7.20.
7.18 The general ventilation rate for the
conservatory and, if necessary, adjoining rooms
could be achieved by the use of background
ventilators. Follow the guidance in paragraph
5.16 whatever the ventilation provisions in the
existing room adjacent to the conservatory.
7.19 For purge ventilation, follow the guidance
given in Table 5.2a.
7.20 Guidance on location and controls is
also given in Tables 5.2a and guidance on
performance standards is given in Table 5.3.
Ventilation
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ONLINE VERSION
Approved Document F
ONLINE VERSION
F1
Section 8: Standards and other publications
Standards
Other publications
BS EN 378-3:2008 Refrigerating systems
and heat pumps. Safety and environmental
requirements. Installation site and personal
protection.
American Conference of Government
Industrial Hygienists (ACGIH)
Industrial ventilation 26th Edition, Manual of
recommended practice.
Available from: www.acgih.org/store
BSI PD CR 1752:1999 Ventilation for buildings –
design criteria for the indoor environment.
BS 5502:2003 Buildings and structures for
agriculture. Various relevant parts including: Part
33:1991 Guide to the control of odour pollution,
AMD 10014 1998. Part 52:1991 Code of
practice for design of alarm systems, emergency
ventilation and smoke ventilation for livestock
housing, AMD 10014 1998.
BS 5454:2000 Recommendations for the storage
and exhibition of archival documents.
BS 5925:1991 Code of practice for ventilation
principles and designing for natural ventilation.
AMD 8930 1995.
BS 7913:1998 Principles of the conservation of
historic buildings.
BS EN 13141-1:2004 Ventilation for buildings.
Performance testing of components/products for
residential ventilation. Externally and internally
mounted air transfer devices.
BS EN 13141-3:2004 Ventilation for buildings.
Performance testing of components/products for
residential ventilation. Range hoods for residential
use.
BS EN 13141-4:2004 Ventilation for buildings.
Performance testing of components/products for
residential ventilation. Fans used in residential
ventilation systems.
BS EN 13141-6:2004 Ventilation for buildings.
Performance testing of components/products for
residential ventilation. Exhaust ventilation system
packages used in a single dwelling.
BS EN 13141-7:2004 Ventilation for buildings.
Performance testing of components/products
for residential ventilation. Performance testing
of a mechanical supply and exhaust ventilation
units (including heat recovery) for mechanical
ventilation systems intended for single family
dwellings.
BS EN 13141-8:2006 Ventilation for buildings.
Performance testing of components/products
for residential ventilation. Performance testing
of unducted mechanical supply and exhaust
ventilation units [including heat recovery] for
mechanical ventilation systems intended for a
single room.
BS EN 13986:2004 Wood-based panels for use
in construction. Characteristics, evaluation of
conformity and marking.
Approved Document F
BRE
BRE Digest 464, Part 1: VOC emissions from
building products. Sources, testing and emission
data, 2002. ISBN 978 1 86081 546 1.
BRE Digest 464, Part 2: VOC emissions from
building products. Control, evaluation and
labelling schemes, 2002. ISBN 978 1 86081 547 8.
BSRIA
Ventilation hygiene toolkit:
BSRIA Facilities Management Specification
1 Guidance to the standard specification for
ventilation hygiene, 2002. ISBN 978 0 86022 454 9.
Chartered Institution of Building Services
Engineers (CIBSE)
Applications Manual AM10: Natural ventilation in
non-domestic buildings, 2005.
ISBN 978 1 80328 756 0.
Applications Manual AM13: Mixed mode
ventilation, 2000. ISBN 978 1 90328 701 4.
CIBSE Guide A: Environmental design, 2006.
ISBN 978 1 90328 766 8.
CIBSE Guide B: Heating, ventilating, air
conditioning and refrigeration, 2005.
ISBN 978 1 90328 758 3.
TM13: Minimising the risk of Legionnaires’
disease, 2002. ISBN 978 1 90328 723 1.
CIBSE Commissioning Codes, available from:
www.cibse.org/index.cfm?go=publications.
view&item=266.
CIBSE TM26 Hygienic maintenance of office
ventilation ductwork, 2000.
ISBN 978 1 90328 711 8.
Defence Estates
Defence Works Functional Standard, Design and
Maintenance Guide 08: Space requirements for
plant access operation and maintenance, 1996.
ISBN 978 1 11772 785 4. Available from:
www.defence-estates.mod.uk/publications/
dmg/dmg_08.pdf
Department for Children, Schools and
Families (DCSF);
Building Bulletin 101, Ventilation of school
buildings, 2006. ISBN 978 0 11271 164 3.
See: www.teachernet.gov.uk/iaq
ONLINE VERSION
Ventilation
41
F1
ON
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VERSION
STANDARDS AND
OTHER
P
PuBLICATIONS
uBLICATIONS
BLICATIONS
Department of Health Estates and
Facilities Division
HTM 03; Part A – Ventilation in healthcare
premises: Design and validation, 2007.
HTM 03; Part B – Ventilation in healthcare
premises: Verification and operational
Management, 2007.
HBN (various).
Energy Saving Trust
Good Practice Guide 192. Designing energy
efficient multi-residential buildings, 1997.
Available from: www.est.org.uk/bestpractice/
index.cfm (archived).
Health and Safety Executive (HSE)
HSE Catering Information Sheet No 10,
Ventilation of kitchens in catering establishments,
2007. Available from: www.hsebooks.com.
HSE Catering Information Sheet No 11, The main
health and safety law applicable to catering,
2000. Available from: www.hsebooks.com.
HSG 258 Controlling airborne contaminants at
work. A guide to local exhaust ventilation (LEV),
2008. ISBN 978 0 71766 298 2.
Legislation
Factories Act 1961, Chapter 34.
Welfare of Farm Animals (England) Regulations
2000, SI 2000/1870.
Welfare of Farm Animals (England) (Amendment)
Regulations 2002, SI 2002/1646.
Welfare of Farm Animals (England) (Amendment)
Regulations 2003, SI 2003/299.
Department for Communities and Local
Government
Planning Policy Statement (PPS) 15: Planning
and the historic environment; DoE, 1994.
Paragraphs 6.1 to 6.40 have been superseded
by Circular 01/2007, Revisions to principles of
selection for listing buildings. Both available at:
www.communities.gov.uk/planningandbuilding/
planning/planningpolicyguidance/
historicenvironment/ppg15.
Review of health and safety risk drivers (BD
2518). Available at:
www.communities.gov.uk/documents/
planningandbuilding/pdf/reviewhealthsafety.pdf.
HSG 193. COSHH Essentials. Accessed on:
www.coshh-essentials.org.uk
HSG 202 General ventilation in the workplace –
Guidance for employers, 2000.
ISBN 978 0 71761 793 7.
L8 Legionnaires Disease: The control of legionella
bacteria in water systems. Approved code of
practice and guidance, 2000.
ISBN 978 0 71761 772 2.
L24 Workplace (Health, Safety and Welfare)
Regulations 1992. Approved Code of Practice
and guidance, 2001. ISBN 978 0 71760 413 5.
HVCA
HVCA DW/144 Specification for sheet metal
ductwork – low, medium and high pressure/air
systems, 1998. ISBN 978 0 90378 327 9.
HVCA DW/154 Specification of plastics ductwork,
2000. ISBN: 0 90378 331 2.
HVCA DW/143 A practical guide to ductwork
leakage testing, 2000. ISBN: 978 0 90378 330 9.
HVCA DW/172 Specification for kitchen
ventilation systems, 2005
ISBN 978 0 90378 329 3.
HVCA TR/19 Guide to good practice. Internal
cleanliness of ventilation systems, 2005.
ISBN 978 0 90378 335 4.
Ventilation
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ONLINE VERSION
Approved Document F
ONLINE VERSION
F1
Appendix A: Performance-based ventilation
Introduction
As specified in the section on Performance, this
Approved Document recommends ventilation
provisions to control both moisture and pollutants
in buildings. In order to do this, acceptable
levels of moisture and other pollutants need to
be defined. This Appendix sets out the levels of
moisture and other pollutants that the provisions
in this Approved Document are designed to
control.
Note that the guidance within this Approved
Document may not be adequate to address
pollutants from flueless combustion space
heaters or from occasional, occupant-controlled
events such as painting, smoking, cleaning or
other high-polluting events. It does not address
the airborne spread of infection or contamination
from outdoor sources. While many of these
considerations could be important factors in
achieving acceptable indoor air quality, solutions
are not ready for inclusion in this guidance, and
indeed indoor air quality may be better controlled
at source (e.g. avoidance, isolation or use of
lower emitting products).
Exposure to total volatile organic compound
(TVOC) levels should not exceed 300 µg/m3
averaged over 8 hours (ECA, 1992).
Control of bio-effluents (body odours) for
adapted individuals (reduction in perception due
to being exposed to the environment for a period
of time) will be achieved by an air supply rate of
3.5 l/s/person (ASHRAE, 2003).
Mould growth can occur whether the dwelling
is occupied or unoccupied, so the performance
criteria for moisture (as set out in Table A2)
should be met at all times, regardless of
occupancy. The other pollutants listed above are
harmful to the occupants only when the dwelling
is occupied.
Assumptions used in applying
performance criteria for dwellings
in Section 5
General
•
For the default option in which the design air
permeability can be any value, dwellings
with ventilation System 1 or 2 are assumed to
have an infiltration of 0.05 ach (air changes
per hour); and dwellings with ventilation
System 3 or 4 are assumed to have no
infiltration.
•
For the alternative option in which the design
air permeability is >5 m3/(h.m2) at 50 Pa,
dwellings with ventilation System 1, 2 or 4 are
assumed to have an infiltration of 0.15 ach,
and dwellings with ventilation System 3 are
assumed to have negligible infiltration, as
discussed in Table 5.2c.
•
The ventilation effectiveness is 1.0.
•
For the purpose of this Approved Document,
for all dwellings (new, and existing where
Part F applies), the moisture criterion is likely
to be met if the moving average surface
water activity of the internal surfaces of
external walls is always less than the value
noted in Table A1 during the heating season,
evaluated over each of the stated averaging
periods. Table A1 is the primary basis
for demonstrating compliance with the
moisture criterion.
Performance criteria for dwellings
The performance criterion for moisture is as
follows:
•
There should be no visible mould on external
walls in a properly heated dwelling with
typical moisture generation.
The principal performance criteria used for other
indoor air pollutants are as follows.
Exposure to the following levels of nitrogen
dioxide (NO2) should not be exceeded:
•
288 µg/m3 (150 ppb) – 1 hour average
(DOH, 2004)
•
40 µg/m (20 ppb) – long-term average
(DOH, 2004).
3
Exposure to the following levels of carbon
monoxide should not be exceeded:
•
100 mg/m3 (90 ppm) – 15 minute averaging
time (DOH, 2004)
•
60 mg/m3 (50 ppm) – 30 minute averaging
time (DOH, 2004)
•
30 mg/m3 (25 ppm) – 1 hour averaging time
(DOH, 2004)
•
10 mg/m3 (10 ppm) – 8 hours averaging time
(DOH, 2004).
Approved Document F
Table A1 Surface water activity
Moving average period
Surface water activity
1 month
0.75
1 week
0.85
1 day
0.95
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As a guide, for new dwellings, for the purpose of
this Approved Document, the moisture criteria
in Table A1 are likely to be met if the moving
average relative humidity (RH) in a room is always
less than the value given in Table A2 during
the heating season, evaluated over each of the
stated averaging periods.
•
–
Room air relative
humidity
1 month
65%
1 week
75%
1 day
85%
The performance criterion for moisture (given
above) is the same as that used in the 2006
edition of Approved Document F. However,
research carried out since 2006 (AltamiranoMedina et al, 2009) has indicated that the values
of relative humidity needed to satisfy the criterion
could be expressed in a different and more
practical way as shown in Table A2. These RH
values may, in general, be slightly less onerous
than those used in the 2006 edition. This may not
be true in all cases and so the ventilation rates
necessary to satisfy the criterion have not been
changed.
•
The principal pollutant to be removed by
whole dwelling ventilation is moisture. The
source rates were taken from BS 5250:2002
Table B.1.
•
It was assumed that local extract removes
100% of the moisture generated in the
bathroom and 50% of the moisture
generated in the kitchen.
•
The rates given in Table 5.1b are the same as
in the 2006 edition.
•
The calculations were based on winter
weather conditions. During warmer spring
and autumn periods, the moisture removal
capacity of the outdoor air will be less (i.e. the
outdoor air on being heated to the internal
temperature within the dwelling will have a
higher relative humidity in the spring and
autumn periods) and additional ventilation
may be required. The provisions for purge
ventilation (e.g. windows) may be used for
this purpose.
•
There are other pollutants which must also be
adequately controlled. These are particularly
important in homes of low occupant density
where moisture production is low for the size
of the property. Levels of volatile organic
compounds were monitored in a BRE study
of uK homes (Dimitroulopoulou et al, 2005).
From these data, the total source production
rate of volatile organic compounds was
determined to be 300 µg/h per m2 of floor
area. To meet the performance criterion of
300 µg/m3, it requires a minimum whole
dwelling ventilation rate of 0.3 l/s per m2 of
internal floor area.
Extract ventilation
•
The principal pollutant to be removed by
extract ventilation is moisture. The source
rates were taken from BS 5250:2002
Table B.1.
•
For intermittent extract:
–
–
Historically, a ventilation rate of 60 l/s
has been specified in the kitchen for the
removal of moisture and there is no strong
justification to amend it. The ventilation
rate removes moisture generated at a
production rate of 2000 g/h. A reduced
ventilation rate of 30 l/s is used for
a cooker hood, owing to the greater
ventilation effectiveness.
Historically, a ventilation rate of 15 l/s has
been specified in the bathroom for the
removal of moisture and there is no strong
justification to amend it. The ventilation
rate removes moisture generated at a
production rate of 400 g/h.
–
In the utility room, it is assumed that the
ventilation rate required is 50% of that in
the kitchen.
–
In WCs, the main pollutant is odour.
Historically, a ventilation rate of 6 l/s has
been specified and there is no strong
justification to amend it.
Ventilation
44
No reason has been found to change the
extract rates, so the rates used in Table
5.1a are the same as used in the 2006
edition of AD F.
Whole dwelling ventilation
Table A2 Indoor air relative humidity
Moving average period
For continuous extract:
Purge ventilation
•
A value of 4 ach has been selected as:
–
it provides a purge ventilation rate an
order of magnitude above whole building
ventilation;
–
it is similar to the ventilation rate provided
by windows in the 1995 edition of
Approved Document F. The calculation
assumes single-sided ventilation for a
dwelling in an urban environment and an
internal/external temperature difference
of 3°C.
ONLINE VERSION
Approved Document F
O N LVENTILATION
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PERFORMANCE-BASED
BASED
Basis of Table 5.2 – Whole dwelling ventilation
rates
•
F1
Exposure to the following levels of carbon
monoxide should not be exceeded:
•
In determining the ventilation rates, the air
supply rates in Table 5.1b have been used.
–
100 mg/m3 (90 ppm) – 15 minute
averaging time (WHO, 2000)
•
For dwellings having an air permeability of
> 5 m3/(h.m2) at 50 Pa, the air supply rate has
been reduced by 0.15 ach to allow for
infiltration.
–
60 mg/m3 (50 ppm) – 30 minute averaging
time (WHO, 2000)
–
30 mg/m3 (25 ppm) – 1 hour averaging
time (WHO, 2000)
–
10 mg/m3 (10 ppm) – 8 hours averaging
time (Department of the Environment,
1994a).
•
To determine the equivalent areas, the
standard air flow equation has been used as
below:
A = 1000.(q/Cd).(r/2.∆P)0.5
Where:
•
A = the background ventilator equivalent
area (mm2)
q = the air supply rate (l/s)
Cd = the discharge coefficient, taken as 0.61
–
Note that the total actual equivalent area
required (AT) is double that derived from the
equation above, which provides the equivalent
area only for air supplied to the dwelling. A
similar equivalent area is required for air to
exit the dwelling. The total equivalent area
determined in this way is given in the guidance
for Systems 1 and 2. Note that in determining
these pressure differences, a meteorological
wind speed of 4 m/s at 10 m height was taken
(based on BS 5925:1991) and an internal/external
temperature difference of 15°C.
Performance criteria for buildings
other than dwellings
The main guidance within this document has
focused on offices. For this, the main criteria
have been:
•
A supply rate, in the absence of tobacco
smoking or other excessive pollutants, of 10
l/s/person, based upon surveys which
indicate that below this level the incidence of
health effects becomes increasingly
significant. This will also satisfy the
requirement of 8 l/s/person needed to control
bio-effluents for unadapted individuals.
•
There should be no visible mould on external
walls in a properly heated building with
typical moisture generation.
•
Exposure to the following levels of nitrogen
dioxide (NO2) should not be exceeded:
–
288 µg/m3 (150 ppb) – 1 hour average
(Department of the Environment, 1996)
–
40 µg/m3 (21 ppb) – annual mean
(WHO, 2005).
Approved Document F
35 mg/m3 (30 ppm) – 8 hours averaging
time (HSE, 2003).
•
Exposure to total volatile organic compound
(TVOC) levels should not exceed 300 µg/m3
averaged over 8 hours (ECA, 1992).
•
Ozone levels should not exceed 100 µg/m3
(Department of the Environment, 1994b).
r = the air density (kg/m3), taken as 1.2
∆P = the pressure across the vent, which
has been taken as 0.6 Pa for single-storey
dwellings and 1.0 Pa for multi-storey
dwellings.
Exposure to the following levels of carbon
monoxide for occupational exposure should
not be exceeded:
Note that the guidance within this Approved
Document may not be adequate to address
pollutants from occasional, occupant-controlled
events such as painting, smoking, cleaning or
other high-polluting events. While these could be
important factors in achieving acceptable indoor
air quality, solutions are not ready for inclusion
in this guidance, and indeed they may be better
controlled at source (e.g. avoidance, isolation or
use of lower emitting products).
Mould growth can occur whether the building
is occupied or unoccupied, so the performance
criteria for moisture (as set-out in Table A1) should
be met at all times, regardless of occupancy. The
other pollutants listed above are harmful to the
occupants only when the building is occupied.
Where the Health and Safety Executive gives
guidance for specific situations, it should be
followed in preference to the guidance given here.
Assumptions used in applying
performance criteria for offices
in Section 2
General
•
The office has an air permeability of 3 m3/
(h.m2) at 50 Pa.
•
At this level of air permeability, in large
buildings (low ratio of surface area to volume
contained), infiltration can be assumed to be
negligible compared with the purposeprovided ventilation.
•
The ventilation effectiveness is 0.9
(for Table 6.1b).
•
For the purposes of this Approved Document,
the moisture criterion will be met if the
surface water activity in a room does not
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exceed the values given in Table A1 during
the heating season.
Extract ventilation
•
Office equipment can emit pollutants including
ozone and organic compounds. For example,
a study by Black and Wortham (1999)
suggests the following emission rates for laser
printers and dry paper copiers assuming
30 minutes use in an hour:
–
25 mg/h for TVOCs
–
3 mg/h for ozone.
To meet the performance criteria for these
pollutants requires an extract rate of 20 l/s per
machine during use.
•
For sanitary accommodation, the extract
rates used for dwellings have been applied.
•
For food and beverage preparation areas, the
extract rates used for dwellings have been applied.
Whole building ventilation
•
•
A number of studies have investigated
ventilation and health in offices (principally
sick building syndrome). Although there is no
clear threshold ventilation rate below which
health suddenly worsens, a number of
sources have identified 10 l/s/p as a
significant level. This can probably be traced
back to an analysis of experimental studies of
office buildings by Mendell (1993). Hence the
recommendation within the Approved
Document is for 10 l/s/p for buildings with no
smoking and no significant pollutant sources.
Increasing the ventilation rate above 10 l/s/p
may improve health (results unclear), but there
are diminishing returns (i.e. the improvement in
health per l/s/p increase in ventilation rate
becomes smaller as the ventilation rate
increases). This suggests that there is little
advantage in increasing the whole building
ventilation rate above 10 l/s/p. Increased
ventilation has a cost in economic and
environmental terms. Having set a ventilation
rate of 10 l/s/p, if further improvements in
indoor air quality are necessary, alternative
approaches should be considered first, e.g.
use of low-emission materials.
Purge ventilation
•
There are normally more options for the
removal of high concentrations of pollutants
from office spaces than for dwellings (e.g.
leaving rooms unoccupied until acceptable
pollutant levels are achieved). Hence, general
guidance has been provided rather than
specifying any ventilation rate(s).
ASHRAE. Handbook 2007: HVAC applications.
Black M S and Wortham A W (1999). Emissions
from office equipment. Proceedings of the 8th
International Conference on Indoor Air quality
and Climate, Indoor Air 99, Edinburgh 8–13
August 1999, Vol. 2, pp 455–459.
BS 5250:2002 Code of practice for the control of
condensation in buildings. BSI.
BS 8233:1999 Code of Practice: Sound insulation
and noise reduction for buildings, BSI.
Department of the Environment (1994a). Expert
panel on air quality standards: Carbon monoxide.
London, HMSO. www.defra.gov.uk/environment/
airquality/panels/aqs/publications/index.htm.
Department of the Environment (1994b). Expert
panel on air quality standards: Ozone. London,
HMSO. www.defra.gov.uk/environment/airquality/
panels/aqs/publications/index.htm.
Department of the Environment (1996). Expert
panel on air quality standards: Nitrogen dioxide.
London, The Stationery Office. www.defra.gov.uk/
environment/airquality/panels/aqs/publications/
index.htm.
Department of Health (2004). Committee on the
Medical Effects of Air Pollutants. Guidance on the
effects on health of indoor air pollutants.
www.advisorybodies.doh.gov.uk/comeap/PDFS/
guidanceindoorairqualitydec04.pdf.
Dimitroulopoulou C, Crump D, Coward S K D,
Brown V, Squire R, Mann H, White M, Pierce B
and Ross D (2005). Ventilation, air tightness and
indoor air quality in new homes. Report BR 477.
BRE bookshop.
ECA (1992). European Concerted Action on
indoor air and its impact on man: Guidelines
for ventilation requirements in buildings.
Working Group Report No. 11. EuR 14449 EN.
Commission of the European Communities,
Luxembourg.
HSE (2003). Occupational exposure limits 2002,
plus supplement 2003. HSE Books.
Mendell M J (1993). Non-specific symptoms
in office workers: a review and summary of
the epidemiologic literature. Indoor Air 3,
pp 227–236.
Ross D I and Wilde D (1999). Continuous
monitoring of nitrogen dioxide and carbon
monoxide levels in UK homes. Proceedings of the
8th International Conference on Indoor Air quality
and Climate, Indoor Air 99, Edinburgh 8-13
August 1999, Vol. 3, pp 147–152.
WHO (2000). Guidelines for air quality.
World Health Organisation, Geneva.
WHO (2005). Air quality guidelines – global
update. World Health Organization, Geneva.
References
Altamirano-Medina H., Mumovic D., Davies M.,
Ridley I. and Oreszczyn T., (2009). Guidelines
to avoid mould growth in buildings, Advanced
Buildings Energy Research, 3, pp 221–236.
Ventilation
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Approved Document F
ONLINE VERSION
Appendix B: Purge ventilation
Introduction
Adequate purge ventilation may be achieved
by the use of openable windows and/or external
doors. This Appendix provides details of
necessary window and door sizes. The diagrams
highlight the window dimensions of importance.
External doors
(including patio doors)
•
For an external door, the height x width of the
opening part should be at least 1/20th of the
floor area of the room. If the room contains
more than one external door, the areas of all
the opening parts may be added to achieve
at least 1/20th of the floor area of the room.
•
If the room contains more than one external
door, the areas of all the opening parts may
be added to achieve at least 1/20th of the
floor area of the room.
•
If the room contains a combination of at least
one external door and at least one openable
window, the areas of all the opening parts
may be added to achieve at least 1/20th of
the floor area of the room.
Windows
•
For a hinged or pivot window that opens 30º
or more or for parallel sliding windows (e.g.
vertical sliding sash windows), the height x
width of the opening part should be at least
1/20th of the floor area of the room.
•
For a hinged or pivot window that opens
between 15º and 30º, the height x width of
the opening part should be at least 1/10th of
the floor area of the room.
•
If the window opens less than 15º it is not
suitable for providing purge ventilation and
other arrangements should be made.
•
If the room contains more than one openable
window, the areas of all the opening parts
may be added to achieve the required
proportion of the floor area. The required
proportion of the floor area is determined by
the opening angle of the largest window in
the room.
•
Note that Approved Document B includes
provisions for the size of escape windows.
The larger of the provisions in Approved
Document B or F should apply in all cases.
F1
Window dimensions
Window opening area = H x W
(H and W are the dimensions of the open area)
Approved Document F
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ONLINE
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VERSION
Further information
The aim of this guidance is to achieve a purge
ventilation rate of 4 ach.
•
It provides a purge ventilation rate of an order
of magnitude above the whole building
ventilation rate.
•
It is similar to the purge ventilation rate
provided by windows historically in ADF.
The guidance contained within this Appendix
is a simplification of guidance in BS5925:1991
(AMD 8930, 1995) Code of practice for ventilation
principles and designing for natural ventilation.
This Appendix has assumed single-sided
ventilation for dwellings in an urban environment
(local wind speed of 2.1m/s) and a summer-time
internal/external temperature difference of 3°C.
It has considered and simplified variations in air
flow rates caused by factors including window
type and window height.
This design guidance should deliver 4 ach in
most cases. Depending on the dwelling design
or the external climate, it may be possible to
achieve this ventilation rate through a smaller
window opening area. BS5925 provides a
good starting point for determining the window
openings required. It may be beneficial to also
seek expert advice.
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Approved Document F
ONLINE VERSION
F1
Appendix C: Example calculations for
ventilation sizing for dwellings
Introduction
This Appendix provides example calculations
for each ventilation system set out in paragraph
5.10. A ground-floor flat and a semi-detached
house have been considered for each system
type. Thus there are eight examples as follows.
Diagram C1 Ground floor flat plan
example
Ground-floor flat:
Example C1 – Background ventilators and
intermittent extract fans
Example C2 – Passive stack ventilation
Example C3 – Continuous mechanical extract
Example C4 – Continuous mechanical supply
and extract
Semi-detached house:
Example C5 – Background ventilators and
intermittent extract fans
Example C6 – Passive stack ventilation
Example C7 – Continuous mechanical extract
Example C8 – Continuous mechanical supply
and extract
It has been assumed that the intended measured
air permeability is > 5 m3/(h.m2) in examples C1,
C2, C5 and C6, and the design air permeability
is ≤ 3 m3/(h.m2) in the other examples.
Details of ground-floor flat
Description
The flat contains the following rooms:
•
kitchen
•
combined living/dining room
•
one double bedroom
•
internal bathroom containing WC, and in
addition
•
all rooms have an external wall except for
the bathroom.
The floor plan is given in Diagram C1.
Assumptions:
•
cooker hood adjacent to cooker hob
•
gross internal volume of the heated space
of 83 m3
•
total floor area of 36 m2
•
two-person occupancy and
•
side-hinged windows 1.0 m high and
openable to 60°.
Approved Document F
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Example C1 Background ventilators and intermittent extract fans
(this is based on Table 5.2a)
Intermittent extract
Room
Intermittent extract rate
Kitchen
30 l/s (adjacent to hob)
Bathroom
15 l/s
Background ventilators
• For a single-storey ground-floor dwelling of 36 m2 floor area, Table 5.2a shows that the equivalent background ventilator area is
35000 mm2 (this includes the additional 10000 mm2 as we are considering a single-storey building).
• To maximise the air flow through the dwelling by encouraging cross ventilation, it is best to locate similar equivalent areas of
background ventilators on opposite sides of the dwelling.
Purge ventilation
• Calculate the percentage window opening area (percentage of floor area) for each room having an external wall.
• using Appendix B with an opening angle of 60° gives: 1/20th of the floor area.
• Therefore, for a living room of 13.5 m2 floor area there should be a window opening area of at least 0.68 m2. This calculation
should be carried out for all habitable rooms.
Example C2 Passive stack ventilation (this is based on Table 5.2b)
Choose appropriate passive stack ventilation provision
Room
Internal duct
diameter (mm)
Internal crosssectional area (mm2)
Kitchen
125
12000
Bathroom
100
12000
Background ventilators
Calculate the total equivalent area of ventilators required for a dwelling as follows:
Step 1: for a single-storey ground-floor dwelling of 36 m2 floor area, Table 5.2b shows that the equivalent background ventilator
area is 35000 mm2 (this includes the additional 10000 mm2 as we are considering a single-storey building).
Step 2: for a PSV in both the kitchen and bathroom, an allowance of 6000 mm2 can be made.
Step 3: 35000 – 6000 = 29000 mm2.
• In addition, the equivalent area must be at least the total cross-sectional area of the ducts (24000 mm2), which it is. It should be
distributed with similar areas on opposite sides of the dwelling (but not in the kitchen and bathroom).
Purge ventilation
• Calculate the percentage window opening area (percentage of floor area) for each room having an external wall.
• using Appendix B with an opening angle of 60° gives: 1/20th of the floor area.
• Therefore, for a living room of 13.5 m2 floor area there should be a window opening area of at least 0.68 m2. This calculation
should be carried out for all habitable rooms.
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Example C3 Continuous mechanical extract (this is based on Table 5.2c)
Continuous extract
Step 1: Whole dwelling ventilation rate is 13 l/s from Table 5.1b.
Step 2: Whole dwelling extract ventilation rate is 21 l/s (from Table 5.1a assuming extract in kitchen and bathroom).
Step 3: Maximum whole dwelling extract rate (i.e. the boost rate) should be at least 21 l/s (with a minimum of 13 l/s in the kitchen and
8 l/s in the bathroom).
The minimum whole dwelling extract rate should be at least 13 l/s (spread between the kitchen and bathroom).
Background ventilators
As the design air permeability is ≤ 3 m3/(h.m2) background ventilators of at least 2500 mm2 equivalent area should be located in
the living room and bedroom.
Purge ventilation
• Calculate the percentage window opening area (percentage of floor area) for each room having an external wall.
• using Appendix B with an opening angle of 60° gives: 1/20 of the floor area.
• Therefore, for a living room of 13.5 m2 floor area there should be a window opening area of at least 0.68 m2. This calculation
should be carried out for all habitable rooms.
Example C4 Continuous mechanical supply and extract with heat recovery
(this is based on Table 5.2d)
Continuous supply and extract
Step 1: Whole dwelling supply ventilation rate is 13 l/s from Table 5.1b.
Step 2: Whole dwelling extract ventilation rate is 21 l/s (from Table 5.1a assuming extract in kitchen and bathroom).
Step 3: Maximum whole dwelling extract rate (i.e. the boost rate) should be at least 21 l/s (with 13 l/s extract in the kitchen and 8 l/s
extract in the bathroom).
The minimum whole dwelling supply rate should be at least 13 l/s.
Purge ventilation
• Calculate the percentage window opening area (percentage of floor area) for each room having an external wall.
• using Appendix B with an opening angle of 60° gives: 1/20th of the floor area.
• Therefore, for a living room of 13.5 m2 floor area there should be a window opening area of at least 0.68 m2. This calculation
should be carried out for all habitable rooms.
Approved Document F
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Details of semi-detached house
Description
Diagram C2 Semi-detached house
ground-floor plan example
The semi-detached house contains the
following rooms:
•
entrance hall/stairway
•
kitchen
•
dining room
•
living room
•
three bedrooms
•
bathroom containing WC, and in addition
•
all rooms have an external wall.
The floor plans are given in Diagrams C2 and C3.
Assumptions
•
cooker hood adjacent to cooker hob
•
gross internal volume of the heated space
of 210 m3
•
total floor area of 84 m2
•
four-person occupancy
•
side-hinged windows 1.0 m high and
openable to a fixed position of 20º.
Diagram C3 Semi-detached house
first-floor plan example
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Example C5 Background ventilators and intermittent extract fans
(this is based on Table 5.2a)
Intermittent extract
Room
Intermittent extract rate
Kitchen
30 l/s (adjacent to hob)
Bathroom
15 l/s
Background ventilators
• For a two-storey semi-detached house of 84 m2 floor area, Table 5.2a shows that the equivalent background ventilator area is
40000 mm2.
• To maximise the air flow through the dwelling by encouraging cross-ventilation, it is best to locate similar equivalent areas of
background ventilators on opposite sides of the dwelling.
Purge ventilation
• Calculate the percentage window opening area (percentage of floor area) for each room having an external wall.
• using Appendix B with an opening angle of 20° gives: 1/10th of the floor area.
• Therefore, for a living room of 14.8 m2 floor area there should be a window opening area of at least 1.48 m2. This calculation
should be carried out for all habitable rooms.
Example C6 Passive stack ventilation (this is based on Table 5.2b)
Choose appropriate passive stack ventilation provision
Room
Internal duct
diameter (mm)
Internal crosssectional area (mm2)
Kitchen
125
12000
Bathroom
125
12000
Background ventilators
Calculate the total equivalent area of ventilators required for a dwelling as follows:
Step 1: for a two-storey semi-detached house of 84 m2 floor area, Table 5.2a shows that the equivalent background ventilator area
is 40000 mm2.
Step 2: for a PSV in both the kitchen and bathroom, an allowance of 6000 mm2 can
be made.
Step 3: 40000 – 6000 = 34000 mm2.
• In addition, the equivalent area must be at least the total cross-sectional area of the ducts (24000 mm2), which it is. It should be
distributed with similar areas on opposite sides of the dwelling (but not in the kitchen and bathroom).
Purge ventilation
• Calculate the percentage window opening area (percentage of floor area) for each room having an external wall.
• using Appendix B with an opening angle of 20° gives: 1/10th of the floor area.
• Therefore, for a living room of 14.8 m2 floor area there should be a window opening area of at least 1.48 m2. This calculation
should be carried out for all habitable rooms.
Approved Document F
ONLINE VERSION
Ventilation
53
F1
NLIN
E VENTILATION
V E R S I SIzING
N
EXAMPLE CALCuLATIONS
ALCO
ALCu
uL
LATIONS
LATIONS
FOR
FOR
VENTILATION
SO
SI
Iz
zIING
NG FOR DWELLINGS
Example C7 Continuous mechanical extract (this is based on Table 5.2c)
Continuous extract
Step 1: Whole dwelling ventilation rate from the list in Table 5.1b is 21 l/s.
• However, minimum whole dwelling ventilation rate = 0.3 x floor area = 0.3 x 84 = 25 l/s.
• Hence, whole dwelling ventilation rate is 25 l/s.
Step 2: Whole dwelling extract rate is 21 l/s (from Table 5.1a assuming extract in kitchen and bathroom).
Step 3: In this case the required whole dwelling ventilation rate is greater than the whole dwelling extract ventilation rate, and
only a minimum whole dwelling extract ventilation rate of 25 l/s is required (with at least 13 l/s in the kitchen and 8 l/s
in the bathroom).
Background ventilators
• As the design air permeability is ≤ 3 m3/(h.m2) background ventilators of at least 2500 mm2 equivalent area should be located
in the living room, dining room and each bedroom.
Purge ventilation
• Calculate the percentage window opening area (percentage of floor area) for each room having an external wall.
• using Appendix B with an opening angle of 15° gives: 1/10th of the floor area.
• Therefore, for a living room of 14.8 m2 floor area there should be a window opening area of at least 1.48 m2. This calculation
should be carried out for all habitable rooms.
Example C8 Continuous mechanical supply and extract with heat recovery
(this is based on Table 5.2d)
Step 1: Calculate the whole dwelling supply ventilation rate:
• Whole dwelling ventilation supply rate for the dwelling from the list in Table 5.1b is 21 l/s.
• However, minimum air supply rate = 0.3 x floor area = 0.3 x 84 = 25 l/s.
• Hence, whole dwelling supply ventilation rate is 25 l/s.
Step 2: Calculate the whole dwelling extract ventilation rate:
• Whole dwelling extract ventilation rate is 21 l/s (from Table 5.1a assuming extract in kitchen and bathroom).
Step 3: Maximum whole dwelling extract ventilation rate (i.e. the boost rate) should be at least 25 l/s (with at least 13 l/s extract in the
kitchen and 8 l/s extract in the bathroom).
• The minimum whole dwelling supply ventilation rate should be at least 25 l/s.
Purge ventilation
• Calculate the percentage window opening area (percentage of floor area) for each room having an external wall.
• using Appendix B with an opening angle of 20° gives: 1/10th of the floor area.
• Therefore, for a living room of 14.8 m2 floor area there should be a window opening area of at least 1.48 m2. This calculation
should be carried out for all habitable rooms.
Ventilation
54
ONLINE VERSION
Approved Document F
ONLINE VERSION
F1
Appendix D: Minimising ingress of external
pollution into buildings in urban areas
Typical urban pollutants that need to be
considered include those covered by the uK Air
quality Strategy (www.defra.gov.uk/environment/
airquality/strategy/index.htm (2007)). These are:
•
carbon monoxide, CO
•
nitrogen dioxide, NO2
•
sulphur dioxide, SO2
•
ozone, O3
•
particles (PM10)
•
benzene
•
1,3-butadiene
•
polycylic aromatic hydrocarbons (PAHs)
•
ammonia
•
lead.
Although nitrogen oxide, NO, is not included
in the uK Air quality Strategy, it is a normal
constituent of combustion discharges and in
many cases (for example, from gas-fired plant)
the largest polluting emitter. Therefore, it also
needs to be taken into account.
Typical pollution emission sources that need to
be considered include:
•
road traffic, including traffic junctions and
underground car parks
•
combustion plant (such as heating
appliances) running on conventional fuels,
most commonly natural gas
•
other combustion processes (for example,
waste incineration, thermal oxidation
abatement systems)
•
discharges from industrial processes
•
fugitive (i.e. adventitious/not effectively
controlled) discharges from industrial
processes and other sources
•
building ventilation system exhaust
discharges
•
construction and demolition sites which
are a source of particles and vapourous
discharges.
Internal contamination of buildings from outdoor
pollution sources therefore depends upon the
pollutant sources, the physical characteristics of
the building and its relation to its surroundings,
the ventilation strategy employed and the
location of the air intake. Whatever type of
ventilation system is used, it is important to
ensure that the intake air is not contaminated.
This is especially important in air quality
management areas where, by definition, pollution
levels of at least one pollutant are already close
to the air quality standards. Simplified guidance
on ventilation intake placement for minimising
ingress of pollutants may be summarised, as in
Table D1.
Control of ventilation intakes
For pollutant sources such as urban road traffic,
whose concentration fluctuates with the time of
day, reducing the flow of external air or closing
ventilation intakes during peak periods of high
external pollutant concentrations, for example
during rush hours, for up to an hour may be
an option.
Air intakes located on a less polluted side of
the building may then be used for fresh air, or
air may be fully recirculated within the building.
Alternatively, the building may be used as a
‘fresh air’ reservoir to supply air during these
short periods. The use of atria as a source of
‘fresh air’ for this purpose may be an option.
However, care must be taken since, for example,
reducing the inflow of external air will also reduce
the outflow of internal air, resulting in a build-up
of internally generated pollutants that need to
be removed. Most modern buildings have low
ceiling heights and therefore the concept of a
substantial ‘fresh air’ reservoir available within
the building may not apply. Further details of
this principle with examples may be found in
Liddament (2000).
In urban areas, buildings are exposed
simultaneously to a large number of individual
pollution sources from varying upwind distances
(long range, intermediate range and short
range) and heights and also over different
timescales. The relationship between these and
their proportionate contribution under different
circumstances governs pollutant concentrations
over the building shell and also internally.
Approved Document F
ONLINE VERSION
Ventilation
55
F1
MINIMISING INGRESS OF EXTERNAL POLLuTION
POLLuTION
POLLu
TION INTO
O
N
L
I
N
E
V
E
R
S
I
O
N
BuILDINGS IN uRBAN
uRBAN AREAS
Table D1 Guidance on ventilation intake placement for minimising ingress
of pollutants
Pollutant source
Recommendation
Local static sources
• Ventilation intakes need to be placed away from the direct impact of short-range pollution
sources, especially if the sources are within a few metres of the building. Some guidance
is given in CIBSE TM21
• Parking areas
• Welding areas
• Loading bays
• Adjacent building exhausts
• Stack discharges
Urban traffic
• Air intakes for buildings positioned directly adjacent to urban roads should be as high as
possible and away from the direct influence of the source so as to minimise the ingress of
traffic pollutants. There will be exceptions to this simple guide and these risks may need
to be measured by modelling. In such cases, it is recommended that expert advice is
sought
• For buildings located one or two streets away, the placement of intakes is less critical
Building features/layout:
• Courtyards
• Intakes should not be located in these spaces where there are air pollutant discharges.
This includes emission discharges from building ventilation system exhausts
• Street canyons (i.e. a canyon
formed in a street between two
rows of tall buildings)
• If air intakes are to be located in these spaces, they should be positioned as far as
possible from the source in an open or well-ventilated area. In addition, steps should
be taken to reduce the polluted source, e.g. parking and loading should be avoided as
pollutants can accumulate in enclosed regions such as courtyards
Multiple sources
• Where there are a large number of local sources, the combined effect of these around
the façade of the building should be measured. The façade experiencing the lowest
concentration of the pollutants would be an obvious choice for locating ventilation intakes
but this will require expert assistance such as numerical and wind tunnel modelling. In
general, however, it is recommended that air intakes be positioned as far away as possible
from the source and at a location where air is free to move around the intake
Weather factors
• In areas where predominant wind comes from opposing directions (e.g. a valley location)
the air intakes and outlets should point in opposite directions
• In complex urban layouts, complex wind flows are likely to occur. In these cases, expert
advice should be sought
Location of exhaust outlets
The location of exhausts is as important as the
location of air intakes. These should be located
such that re-entry to a building, or ingestion into
other nearby buildings, is minimised (for both
natural and mechanical intakes) and such that
there is no adverse effect on the surrounding
area. Guidance on outlet placement may be
summarised as follows:
•
•
•
Exhausts should be located downstream of
intakes where there is a prevailing wind
direction
Exhausts should not discharge into
courtyards, enclosures or architectural
screens as pollutants tend to build up in such
spaces and do not disperse very readily
•
Where possible, pollutants from stacks
should be grouped together and discharged
vertically upwards. The increased volume will
provide greater momentum and increased
plume height. This is common practice where
there are a number of fume cupboard
discharges; greater plume height dispersion
can be achieved by adding the general
ventilation exhaust.
References
CIBSE (1999). CIBSE Technical Memorandum
TM21, Minimising pollution at air intakes.
ISBN 978 0 90095 391 0.
Liddament MW (2000) Chapter 13: ‘Ventilation
strategies’, Indoor Air Quality Handbook.
McGraw-Hill.
It is recommended that stacks should
discharge vertically upwards and at high level
to clear surrounding buildings and so that
downwash does not occur
Ventilation
56
ONLINE VERSION
Approved Document F
ONLINE VERSION
F1
Index
A
C
E
Access for maintenance 5.2, 6.6–6.7,
Diagram 4
Agricultural buildings 3.3, Table 6.3
Air change rate Appendix A
Car parks 6.20
Infiltration assumption 4.14
Offices 6.9–6.13, Table 6.1b
Purge ventilation 5.7
Air extract rate
See Extract ventilation rates
Air flow rate testing 2.1, 4.42–4.43
Air intakes Appendix D, Table D1
Air permeability 4.13–4.14, 5.10
Definition 3.1
Air recirculation 6.5
Air supply rate 6.13, Table 6.1b
Airtightness 4.12–4.13
Definition 3.1
Allergens 4.31
Ancient monuments 3.11
Animal husbandry Table 6.3
Approved Document F
Conventions 1.8
Limitations on requirements 2.2–2.3
Purpose 1.1–1.5
Types of work covered 3.2
Architectural interest 3.11
Art galleries Table 6.3
Assembly halls Table 6.3
Atria Table 6.3
Automatic control 4.20–4.22
Definition 3.1
Call centres Table 6.3
Car parks 6.18–6.21
Catering
See Kitchens
Cellar
Definition 3.1
CE marking 3.22
Change of use 3.17–3.18, 7.1
Cleanrooms Table 6.3
Closable opening
Definition 3.1
Codes of practice page 40–41
Combustion appliances 1.3, 5.3, 7.24,
Appendix D
Commissioning 2.1, 4.44–4.46
Common space Table 6.3
Definition 3.1
Communal residential buildings
Table 6.3
Competent person self-certification
schemes 3.5–3.8
Compliance with requirements
1.2–1.3, 1.10
Materials and workmanship 3.22, 3.26
Self-certification 3.7
Computer rooms Table 6.3
Conservation areas 3.11
Conservatories
Addition to existing dwelling
7.16–7.20
Ventilation through 5.16, Diagram 4
Continuous mechanical extract (MEV)
Diagram 2a, Table 5.2c
Example calculations Appendix C3,
Appendix C7
Performance testing Table 5.3
Continuous mechanical supply and
extract with heat recovery (MVHR)
Diagram 2a, Table 5.2d
Example calculations Appendix C4,
Appendix C8
Performance testing Table 5.3
Continuous operation
Definition 3.1
Controls 4.18–4.22
Dwellings Table 5.2a–Table 5.2d
Offices Table 6.2c
Cooker hoods Table 5.3
Educational buildings Table 6.3
Effectiveness of ventilation 4.28–4.29
Electrical work 3.10
Emergency repairs 3.9
Energy efficiency 4.5
Equivalent (ventilator) area 4.26–4.27,
Table 5.2a–Table 5.2d
Definition 3.1
European legislation 3.22
European Standards 3.30
European Technical Approval 3.22,
3.29, 4.17
Exemptions 3.3
Exhaust outlets Appendix D
Existing buildings 7.1–7.24
Additional habitable rooms 7.7–7.10
Additional wet rooms 7.11–7.15
Addition of conservatory 7.16–7.20
Kitchen and bathroom refurbishment
7.6, 7.21–7.24
Replacement windows 7.2–7.6
Extensions
See Existing buildings
External pollution
Minimising ingress Appendix D
Extract ventilation 4.15, 5.5
Definition 3.1
Extract ventilation rates
Dwellings Table 5.1a, Appendix A,
Appendix C
Offices 6.9–6.13, Table 6.1a,
Appendix A
Extract ventilators
Additional wet rooms 7.12
Controls Table 6.2c
Location Table 6.2b
Noise 4.36
Performance testing Table 5.3
B
Background ventilators
Additional rooms 7.8
Configurations Diagram 1
Definition 3.1
Equivalent area 4.26–4.27
With intermittent extract fans Diagram
2a, Table 5.2a, Appendix C1,
Appendix C5
Performance testing Table 5.3
See also Trickle ventilators
Basements 5.11–5.13
Definition 3.1
Bathrooms
Additional 7.11–7.15
Definition 3.1
Extract ventilation rates Table 5.1a,
Appendix A
Refurbishment 7.6, 7.21–7.24
BCB
See Building Control Body (BCB)
British Standards page 41
BS 5440-1 Table 6.2a
BS 7913: 1998 3.13
BS 8233:1999 4.36
BS EN 13141: 2004 4.26, 4.36,
Table 5.3
BS EN 13986: 2004 4.30
Broadcasting studios Table 6.3
Building Control Body (BCB)
Definition 3.1
Demonstrating compliance 3.7, 3.22,
3.26
Notification of work 3.4–3.7
Building log book 4.49
Building Regulations 2.1
Approved Document F
D
Darkrooms Table 6.3
Dealing rooms Table 6.3
Demand-controlled ventilation 4.18
Doors
Purge ventilation Appendix B
undercuttting 7.13
Ductwork 4.46
Dust mites 4.31–4.32
Dwellings
Additional room 7.7–7.20
Example calculations Appendix C,
Diagram C1–C3
New 5.1–5.16
Performance criteria Appendix A
Refurbishment of kitchen or bathroom
7.21–7.24
ONLINE VERSION
F
Factories Table 6.3
Fan noise 4.36
Fire precautions 4.37
Floor area 3.3
Food preparation areas
See Kitchens
Formaldehyde emission 4.30
Free area 4.26
Definition 3.1
G
Greenhouses 3.3
Gross internal volume
Definition 3.1
H
Habitable room
Definition 3.1
Health and safety 3.31–3.32
Healthcare buildings Table 6.3
Heat recovery ventilators 7.8
See also Continuous mechanical
supply and extract with heat
recovery (MVHR)
High-rise buildings Table 6.3
Historic buildings 3.11–3.16
Horticultural buildings Table 6.3
Hospital buildings Table 6.3
Hotels Table 6.3
House dust mite (HDM) 4.31–4.32
Humidity-controlled devices 4.20
Ventilation
57
F1
INDEX
ONLINE VERSION
I
N
Indoor air relative humidity Table A2
Indoor pollutants 4.9–4.10
Outdoor air supply rate 6.13
Performance criteria Appendix A
Source control 4.30–4.33
Industrial buildings Table 6.3
Infiltration 4.11–4.14
Definition 3.1
Information provision 4.47–4.49
Installation 4.39–4.41
Institutional (residential) buildings
Table 6.3
Intakes Table D1, Appendix D
Intermittent extract fans
With background ventilators Diagram
2a, Table 5.2a, Appendix C1,
Appendix C5
Intermittent operation
Definition 3.1
Internal rooms 5.14–5.16, Diagram 3,
Diagram 4
National Parks 3.11
Natural ventilation 4.16
Offices 6.14, Table 6.2a–Table 6.2b
See also Passive stack ventilation
(PSV)
New buildings
Dwellings 5.1–5.16
Other than dwellings 6.1–6.21
Noise 4.34–4.36
Notification of work 3.4–3.10
K
Kitchens Table 6.3
Additional 7.11–7.15
Extract ventilation rates Appendix A
Dwellings Table 5.1a
Offices 6.10, Table 6.1a
Refurbishment 7.6, 7.21–7.24
L
Laboratories Table 6.3
Legionella contamination 6.4
Legislation page 41, page 42
European 3.22
Libraries Table 6.3
Limitation on requirements 2.2–2.3
Listed buildings 3.11
Live-work units 3.19
M
Maintenance
Access Diagram 4, 5.2, 6.6–6.7
Instructions 4.49
Manual control 4.19, Table 5.2a–
Table 5.2d
Definition 3.1
Material change of use 3.17–3.18, 7.1
Materials and workmanship 3.21–3.23
Mechanical ventilation 4.16
Access for maintenance 6.6–6.7
Air flow rate testing 4.42–4.46
General considerations 6.1–6.5
Offices 6.9–6.13, 6.15
Outdoor air supply rate 6.13,
Table 6.1b
See also Continuous mechanical
extract (MEV); Continuous
mechanical supply and extract
with heat recovery (MVHR)
Minor works 3.10
Mixed-mode ventilation 4.16, 6.16
Mixed use buildings 3.19–3.20
Modular buildings 4.38
Moisture
See Water vapour
Museums Table 6.3
Ventilation
58
O
Occupancy sensors 4.22
Occupiable room
Definition 3.1
Offices 6.8–6.16
Extract ventilation rates Table 6.1a,
Appendix A
Location of ventilators Table 6.2b
Printers and photocopiers 6.10,
Appendix A
Purge ventilation 6.12
Ventilation provisions Table 6.2a
Whole building/dwelling ventilation
6.11, Table 6.1b
Operating and maintenance
instructions 4.49
Outdoor air supply rate 6.13, Table 6.1b
P
Paints 4.30
Passive stack ventilation (PSV) 5.7,
Diagram 2a, Table 5.2b, Appendix C2
Definition 3.1
Example calculations Appendix C6
Offices Table 6.2a
Performance testing Table 5.3
Performance
Criteria 4.23–4.25, Appendix A
Test methods Table 5.3
Ventilation effectiveness 4.28–4.29
Permanent opening
Definition 3.1
See also Doors; Windows
Plant rooms Table 6.3
Access 6.7
Pollutants
See External pollution; Indoor
pollutants
Portable buildings 4.38
Positive input ventilation 4.17
Pressure-controlled ventilators
4.20, 4.21
Prison cells Table 6.3
Product certification schemes
3.24–3.26
Publications (excluding BSI and
European Standards) page 41–42
BRE Digest 464 4.30
Building log book toolkit (CIBSE
TM31, 2006) 4.49
Code of practice for ground floor,
multi-storey and underground car
parks (APEA) 6.21
Domestic ventilation compliance
guide (CLG) 4.39–4.40, 4.43
House dust mites (WHO, 2008) 4.32
Internal cleanliness of ventilation
systems (HVCA TR/19) 6.7
Legionnaires’ disease: the control
of Legionella bacteria in water
systems (HSE) 6.4
Minimising the risk of Legionnaires’
disease (CIBSE TM13) 6.4
Mixed mode ventilation (CIBSE
AM13) 6.16
Natural ventilation in non-domestic
buildings (CIBSE AM10) 6.14,
Table 6.2a
Occupational exposure limits for
limiting concentration of exhaust
pollutants (Health and Safety Pub
EH40) 6.21
Performance testing of products for
residential ventilation (EST/BRE)
Table 5.3
Practical guide to ductwork leakage
testing (HVCA DW/143) 4.46
Review of health and safety risk
drivers (CLG BD 2518) 4.32
Space requirements for plant access
operation and maintenance
(Defence Works Functional
Standard, D&M Guide 08) 6.7
Specification for plastics ductwork
(HVCA DW/154) 4.46
Specification for sheet metal
ductwork (HVCA DW/144) 4.46
Ventilation hygiene toolkit (CIBSE) 6.7
Purge ventilation 4.15
Controls Table 6.2c
Definition 3.1
Dwellings 5.7, Table 5.2a–Table 5.2d
Extract ventilation rates Appendix A
Offices 6.12, Table 6.2b
Windows and doors Appendix B
Purpose-provided ventilation 4.11–4.12
Definition 3.1
R
Range hoods Table 5.3
Recirculated air 6.5
Refurbishment
See Existing buildings
Relative humidity Table A2
Replacement windows 7.2–7.6
Retail premises Table 6.3
S
Sanitary accommodation Table 6.3
Additional 7.11–7.15
Controls 4.20
Definition 3.1
Extract ventilation rates Appendix A
Dwellings 5.5, Table 5.1a
Offices 6.10, Table 6.1a
Refurbishment 7.6, 7.21–7.24
Schools Table 6.3
Shops Table 6.3
Shower rooms 7.6, 7.11–7.15
Single-sided ventilation Diagram 2b
Solar control 6.2
Source control 4.30–4.33
Sports centres Table 6.3
Stack effect
Definition 3.1
Standards 3.27–3.30, page 40–41
European 3.30
See also British Standards
Standards rooms Table 6.3
Supply air windows 4.17
Surface water activity Table A1
Definition 3.1
System options 5.10, Diagram 2a
ONLINE VERSION
Approved Document F
INDEX
ONLINE VERSION
F1
T
Technical specifications 3.27–3.30
Temporary buildings 3.3
Test methods Table 5.3
Tobacco smoke 4.4
Traditional constructions 3.11–3.16
Transportation buildings Table 6.3
Trickle ventilators 4.19, 4.20, 4.21
Replacement windows 7.3–7.5, 7.6
U
Utility rooms
Definition 3.1
Extract ventilation rates Table 5.1a,
Appendix A
Refurbishment 7.6
V
Ventilation
Control 4.18–4.22, Table 6.2c
Definition 3.1
Effectiveness 4.28–4.29
Purpose 4.2–4.3, 4.6–4.10
Requirements 2.1
Strategy 4.15–4.17
Types 4.11–4.14
Volatile organic compounds (VOCs)
4.30
W
Warehouses Table 6.3
Washrooms 6.10, Table 6.1a
Water vapour
Performance criteria Appendix A
Source control 4.30
Wet room
Definition 3.1
See also Bathrooms; Kitchens
Whole building/dwelling ventilation
4.15
Additional wet rooms 7.12
Controls Table 6.2c
Definition 3.1
Ventilation rates
Dwellings Table 5.1b, Appendix A
Offices 6.11, Table 6.1b, Appendix A
Windows
Purge ventilation Appendix B
Replacement 7.2–7.6
Workmanship 3.21–3.23
Workplace (Health, Safety and
Welfare) Regulations 1992 3.31–3.32
Approved Document F
ONLINE VERSION
Ventilation
59
ONLINE VERSION
MAIN CHANGES IN THE
VENTILATION REQUIREMENTS
FOR BUILDINGS IN 2010
1. This edition of Approved Document F,
Ventilation, replaces the 2006 edition and
comes into force on 1 October 2010.
2. The following are the main changes to the
legal requirements in the Building Regulations
2010 and the Building (Approved Inspectors
etc) Regulations 2010, and in the technical
guidance in Approved Document F.
Changes in the legal requirements
3. All fixed mechanical ventilation systems, where
they can be tested and adjusted, shall be
commissioned and a commissioning notice
given to the Building Control Body.
4. For mechanical ventilation systems installed in
new dwellings, air flow rates shall be measured
on site and a notice given to the Building
Control
Body. This shall apply to intermittently-used
extract fans and cooker hoods, as well as
continuously running systems.
Main changes made by the
2010 amendments
This 2010 edition, incorporating the further 2010
amendments reflects the changes made as a result
of the Building Regulations 2010 and Building
(Approved inspector etc) Regulations 2010. The
changes mainly reflect regulation number changes
as a result of re-ordering. There have been no
amendments to the substantive requirements
in Schedule 1 (i.e. Parts A to P) of the Building
Regulations.
Please note the simplification of the definition of
‘room for residential purposes’ in regulation 2 of
the Building Regulations 2010. Please also note
that L1(c) has now become regulation 40.
APPROVED DOCUMENTS
The following documents have been approved
and issued by the First Secretary of State for the
purpose of providing practical guidance with
respect to the requirements of the Building
Regulations 2010.
Approved Document A: Structure
2004 edition incorporating 2010 amendments
Approved Document B (Fire safety) – Volume
1: Dwellinghouses
2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) – Volume
2: Buildings other than dwellinghouses
2006 edition incorporating 2007 and 2010
amendments
Approved Document C: Site preparation and
resistance to contaminants and moisture
2004 edition incorporating 2010 amendments
Approved Document D: Toxic substances
1992 edition incorporating 2002 and 2010
amendments
Approved Document E: Resistance to the
passage of sound
2003 edition incorporating 2004 and 2010
amendments
Approved Document K: Protection from falling
collision and impact
1998 edition incorporating 2000 and 2010
amendments
Approved Document L1A: Conservation of
fuel and power – New dwellings
2010 edition incorporating further 2010 amendments
Approved Document L1B: Conservation of
fuel and power – Existing dwellings
2010 edition incorporating further 2010 and 2011
amendments
Approved Document L2A: Conservation of
fuel and power – New buildings other than
dwellings
2010 edition incorporating further 2010 amendments
Approved Document L2B: Conservation of
fuel and power – Existing buildings other than
dwellings
2010 edition incorporating further 2010 and 2011
amendments
Approved Document M: Access to and use of
buildings
2004 edition incorporating 2010 amendments
Approved Document F: Ventilation
2010 edition incorporating further 2010 amendments
Approved Document N: Glazing – safety in
relation to impact, opening and cleaning
1998 edition incorporating 2000 and 2010
amendments
Changes in the technical guidance
Approved Document G: Sanitation, hot water
safety and water efficiency
2010 edition incorporating further 2010 amendments
Approved Document P: Electrical safety –
Dwellings
2006 edition incorporating 2010 amendments
6. Ventilation provisions have been increased for
dwellings with a design air permeability tighter
than or equal to 5 m3/(h.m2) at 50 Pa.
Approved Document H: Drainage and waste
disposal
2002 edition incorporating 2010 amendments
Approved Document to support regulation 7:
Materials and workmanship
1999 edition incorporating 2010 amendments
7. For passive stack ventilators, the stack
diameter has been increased to 125 mm for all
room types. Use of passive stack ventilation in
inner wet rooms has been clarified.
Approved Document J: Combustion
appliances and fuel storage systems
2010 edition incorporating further 2010 amendments
5. The owner shall be given sufficient information
about the ventilation system and its
maintenance
requirements so that the ventilation system can
be operated to provide adequate air flow.
8. The guidance for ventilation when a kitchen
or bathroom in an existing dwelling is
refurbished has been clarified.
9. Reference is made to a new Domestic ventilation
compliance guide for guidance on installing,
inspecting, testing and commissioning
ventilation systems in dwellings. Guidance in
Appendices D and E of the 2006 edition of
Approved Document F, on installing passive
stack ventilators and fans in dwellings, can
now be found in Section 2 of the new guide.
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Building Regulations 2010
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Ventilation
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