TGD Part L - Conservation of Fuel and Energy (2007) (reprint 2008)

TGD Part L - Conservation of Fuel and Energy (2007) (reprint 2008)
Building Regulations (Part L Amendment) Regulations 2008 (S.I. No. 259 of 2008)
Technical Guidance Document L – Conservation of Fuel and Energy – Dwellings
Introduction
In 2007, an amendment to Part L was made dealing only with dwellings (SI No. 854 of 2007), and
an associated TGD L "Conservation of Fuel and Energy - Dwellings " dealing only with dwellings
was published.
In 2008, an amendment to Part L was made to introduce the energy and CO2 calculation
methodology for buildings other than dwellings (SI No. 259 of 2008). This amendment also took
the opportunity to consolidate all Part L amendments since 1997, thus revoking all previous
amendments (i.e. SI No. 873 of 2005, SI No. 854 of 2007 etc).
As a result, TGD L "Conservation of Fuel and Energy - Dwellings" 2007 needs to be amended as set out
in the table below. There are also some other minor amendments and corrections included.
Amd.
No.
L(i)
L(ii)
L(iii)
L(iv)
L(v)
L(vi)
Text Affected
Cover Page, Building Regulations 2007 to read Building Regulations 2008
Inside Cover Page, Building Regulations 2007 to read Building Regulations 2008
Page 3, Introduction, line 6 to read: Building Regulations (Part L Amendment) Regulations 2008
(S.I. No. 259 of 2008).
Page 3, Transitional Arrangements, replace 1 July 2009 with 30 June 2009
Page 5, Building Regulations – The Requirement, line 2 to read: Building Regulations (Part L
Amendment) Regulations 2008 (S.I. No. 259 of 2008).
The Second Schedule to read
Conservation of Fuel and Energy
L1
A building shall be designed and constructed so as to ensure that the energy
performance of the building is such as to limit the amount of energy required for the
operation of the building and the amount of CO2 emissions associated with this energy
use insofar as is reasonably practicable.
L2
For existing dwellings, the requirements of L1 shall be met by:
(a) limiting heat loss and, where appropriate, maximising heat gain through the fabric
of the building;
(b) controlling, as appropriate, the output of the space heating and hot water systems;
(c) limiting the heat loss from pipes, ducts and vessels used for the transport or storage
of heated water or air;
(d) providing that all oil and gas fired boilers installed in existing dwellings shall meet
a minimum seasonal efficiency of 86% where practicable.
L3
For new dwellings, the requirements of L1 shall be met by:
(a) providing that the energy performance is such as to limit the calculated primary
energy consumption and related CO2 emissions insofar as is reasonably practicable,
when both energy consumption and CO2 emissions are calculated using the
Dwelling Energy Assessment Procedure (DEAP) published by Sustainable Energy
Ireland;
(b) providing that a reasonable proportion of the energy consumption to meet the
energy performance of a dwelling is provided by renewable energy sources;
(c) limiting heat loss and, where appropriate, availing of heat gain through the fabric of
the dwelling;
(d) providing and commissioning energy efficient space and water heating systems
with efficient heat sources and effective controls;
(e) providing to the dwelling owner sufficient information about the dwelling, the fixed
building services and their maintenance requirements so that the dwelling can be
operated in such a manner as to use no more fuel and energy than is reasonable;
(f) providing that all oil and gas fired boilers shall meet a minimum seasonal efficiency
of 86%.
Paragraph 0.1.2, replace Regulation L2(a) with Regulation L3(a)
L(vii)
L(viii)
Paragraph 0.1.7, replace Regulation L3 with Regulation L2(d)
Paragraph 0.5, at end of Definitions, add:
0.5.1 APPLICATION TO BUILDINGS OF
ARCHITECTURAL OR HISTORICAL
INTEREST
Part L does not apply to works (including extensions) to an existing building which is a
“protected structure” or a ‘proposed protected structure” within the meaning of the Planning and
Development Act 2000 (No 30 of 2000).
Nevertheless, the application of this Part may pose particular difficulties for habitable buildings which,
although not protected structures or proposed protected structures, may be of architectural or historical
interest.
Works such as the replacement of doors, windows and rooflights, the provision of insulated dry lining and
damp-proofing to walls and basements, insulation to the underside of slating and provision of roof vents
and ducting of pipework could all affect the character of the structure.
In general, the type of works described above should be carefully assessed for their material and visual
impact on the structure.
Historic windows and doors should be repaired rather than replaced, and drylining and dampproofing
should not disrupt or damage historic plasterwork or flagstones and should not introduce further moisture
into the structure.
Roof insulation should be achieved without damage to slating (either during the works or from erosion
due to condensation) and obtrusive vents should not affect the character of the roof.
In specific cases, relaxation of the values proposed may be acceptable, to the local building control
authority, if it can be shown to be necessary in order to preserve the architectural integrity of the particular
building.
For more guidance on appropriate measures see “Planning Guidelines No. 9: Architectural Heritage
Protection - Guidelines for Planning Authorities” published by the Department of the Environment,
Heritage and Local Government.
L(ix)
Paragraph 1.1.1, replace Regulation L2(a) with Regulation L3(a)
L(x)
Paragraph 1.1.2, replace Regulation L2(a) with Regulation L3(a)
L(xi)
Paragraph 1.2.1, line 3 and last line, replace Regulation L2(b) with Regulation L3(b)
L(xii)
Paragraphs 1.3.2.2; 1.4.1.1; 1.5.5.1; 2.1.2.2; 2.2.1.1; 2.2.2.1 & Other Publications, replace
(to be published) with (available on www.environ.ie)
L(xiii)
Paragraph 1.4.1.1, replace Regulation L2(d) with Regulation L3(d) and replace Regulation L2(e) with
Regulation L3(f)
L(xiv)
Paragraphs 1.4.4.3; 2.2.4.3 and Standards referred to: replace –400oC with –40oC
L(xv)
Paragraph 1.3.3.2 (b), to read: Adopt details that are similar to, or demonstrated as equivalent to, generic
details that have been assessed as limiting thermal bridging to an equivalent level to that set out in Table
D1 of Appendix D. A set of such details for typical constructions has been developed in consultation with
relevant construction industry organisations and is available in a document “Limiting Thermal Bridging
and Air Infiltration – Acceptable Construction Details” (available on www.environ.ie). The procedure for
assessing the performance of specific details is outlined in Appendix D.
L(xvi)
Paragraph 1.5.4.7, in second last sentence replace Paragraph 1.3.4.3 with Paragraph 1.3.4.4
L(xvii) Paragraph 2.1.3.2, second paragraph to read: Adopt details that are similar to, or demonstrated as
equivalent to, generic details that have been assessed as limiting thermal bridging to an equivalent level
to that set out in Table D1 of Appendix D. A set of such details for typical constructions has been
developed in consultation with relevant construction industry organisations and is available in a
document “Limiting Thermal Bridging and Air Infiltration – Acceptable Construction Details”
(available on www.environ.ie).
L(xviii) Paragraph 2.2.1.1, replace Regulation L3 with Regulation L2(d)
L(xix)
A.4.1, Table A4: replace 0.23 with 0.28 and insert new item as follows “Facing wall not exposed,
corridor above and below
0.40”
L(xx)
B.7.1, Table 18 to read Table B18
L(xxi)
B.7.1, Tables B19, B20 & B21, replace column heading “Total Thickness of insulation (mm)” with
“Exposed Perimeter/Area (P/A)(m-1)” and replace text “W-Value of construction (W/m2K)” with “Total
thickness of insulation (mm)”
L(xxii) Paragraph C.1, replace Regulation L2(a) with Regulation L3(a)
L(xxiii) D.4 replace BRE IP 1/07 with BRE IP 1/06
03/03/2008
08:42
Page 1
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Building Regulations 2007
L
Conservation of Fuel and Energy - Dwellings
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Conservation of Fuel
and Energy - Dwellings
L
Building
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Te c h n i c a l
Guidance
Document
Building Regulations 2007
Technical Guidance Document L
Conservation of Fuel and Energy - Dwellings
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Contents
Page
Introduction
3
Transitional Arrangements
The Guidance
Technical Specifications
Materials and Workmanship
Interpretation
3
3
3
4
4
Part L - The Requirement
5
Section 0: General Guidance
0.1
Application of the Regulations
0.1.2
New Dwellings
0.1.7
Existing Dwellings
7
7
8
0.2
Technical Risks and Precautions
0.2.1
General
0.2.2
Fire Safety
0.2.3
Ventilation
9
9
9
9
0.3
Thermal Conductivity and Thermal Transmittance
9
0.4
Dimensions
10
0.5
Definitions
11
Section 1: New Dwellings
1.1
Limitation of Primary Energy Use and CO2 Emissions
13
1.2
Renewable Energy Technologies
15
1.3
Building Fabric
1.3.1
General
1.3.2
Fabric Insulation
1.3.3
Thermal Bridging
1.3.4
Building Envelope Air Permeability
17
17
17
19
20
1.4
Building Services
1.4.1
General
1.4.2
Heating Appliance Efficiency
1.4.3
Space Heating and Hot Water Supply System Control
1.4.4
Insulation of Hot Water Storage Vessels, Pipes and Ducts
1.4.5
Mechanical Ventilation Systems
21
21
21
21
22
22
1
1.5
Construction Quality and Commissioning of Services
General
1.5.1
1.5.2
Insulation Continuity and Air Permeability
1.5.3
Thermal Bridging
1.5.4
Air Permeability Pressure Tests
1.5.5
Commissioning of Space and Water Heating Systems
23
23
23
23
23
24
1.6
User Information
25
Section 2: Existing Dwellings
2.1
Building Fabric
2.1.1
General
2.1.2
Fabric Insulation
2.1.3
Thermal Bridging
2.1.4
Air Permeability
27
27
27
29
31
2.2
Building Services
2.2.1
General
2.2.2
Heating Appliance Efficiency
2.2.3
Space Heating and Hot Water Supply System Control
2.2.4
Insulation of Hot Water Storage Vessels, Pipes and Ducts
32
32
32
32
33
Appendices
A
Calculation of U-values
35
B
Fabric Insulation: Additional Guidance for Common Constructions,
including Tables of U-values
43
C
Reference Values for Calculation of Maximum Permitted Energy
Performance Coefficient (MPEPC) and Maximum Permitted
Carbon Performance Coefficient (MPCPC)
65
D
Thermal Bridging at Junctions and around Openings
67
E
Achieving Compliance with respect to EPC and CPC
69
STANDARDS AND OTHER REFERENCES
2
71
Building Regulations 2007
Technical Guidance Document L
Conservation of Fuel and Energy – Dwellings
Introduction
This document has been published by the Minister
for the Environment, Heritage and Local Government
under article 7 of the Building Regulations 1997. It
provides guidance in relation to the application of
Part L of the Second Schedule to the Regulations as
inserted by Building Regulations (Amendment)
Regulations 2007 (S.I. No. 854 of 2007). The
guidance in this document applies to dwellings, both
new and existing. The guidance in relation to the
application of Part L contained in Technical Guidance
Document L - Conservation of Fuel and Energy (May
2006 Edition) continues to apply to all other new and
existing buildings.
The document should be read in conjunction with
the Building Regulations 1997-2007 and other
documents published under these Regulations.
In general, Building Regulations apply to the
construction of new buildings and to extensions and
material alterations to existing buildings. In addition,
certain Parts of the Regulations, including Part L,
apply to existing buildings where a material change of
use takes place.
Transitional Arrangements
In general, this document applies to works to new
dwellings, where the work commences or takes
place, as the case may be, on or after 1 July 2008.
Insofar as the guidance contained therein relates to
dwellings, Technical Guidance Document L Conservation of Fuel and Energy (2006 Edition)
ceases to have effect from 1 July 2008.
However, the foregoing document may continue to
be used in the case of dwellings:
-
where the work, material alteration or the change
of use commences or takes place, as the case may
be, on or before 30 June 2008, or
-
where planning approval or permission has been
applied for on or before 30 June 2008, and
substantial work has been completed by 1 July
2009.
Where the works involve the installation of oil or gas
fired boilers in either a new or existing dwelling, the
relevant aspects of this guidance applies to works
undertaken after the 31 March 2008.
Substantial work has been completed” means that
the structure of the external walls has been erected.
The Guidance
The materials, methods of construction, standards
and other specifications (including technical
specifications) that are referred to in this document
are those which are likely to be suitable for the
purposes of the Building Regulations (as amended).
Where works are carried out in accordance with the
guidance in this document, this will, prima facie,
indicate compliance with Part L of the Second
Schedule to the Building Regulations.
However, the adoption of an approach other than
that outlined in the guidance is not precluded
provided that the relevant requirements of the
Regulations are complied with. Those involved in the
design and construction of a building may be
required by the relevant building control authority to
provide such evidence as is necessary to establish
that the requirements of the Regulations are being
complied with.
Technical Specifications
Building Regulations are made for specific purposes,
e.g. to provide, in relation to buildings, for the health,
safety and welfare of persons, the conservation of
energy, and access for people with disabilities.
Technical specifications (including harmonised
European Standards, European Technical Approvals,
National Standards and Agrement Certificates) are
relevant to the extent that they relate to these
considerations.
Any reference to a technical specification is a
reference to so much of the specification as is
relevant in the context in which it arises. Technical
specification may also address other aspects not
covered by the Regulations.
A reference to a technical specification is to the
latest edition (including any amendments,
supplements or addenda) current at the date of
publication of this Technical Guidance Document.
However, if this version of the technical specification
is subsequently revised or updated by the issuing
body, the new version may be used as a source of
guidance provided that it continues to address the
relevant requirements of the Regulations.
3
Materials and Workmanship
Under Part D of the Second Schedule to the Building
Regulations, building work to which the Regulations
apply must be carried out with proper materials and
in a workmanlike manner. Guidance in relation to
compliance with Part D is contained in Technical
Guidance Document D.
Interpretation
In this document, a reference to a section, paragraph,
appendix or diagram is, unless otherwise stated, a
reference to a section, paragraph, appendix or
diagram, as the case may be, of this document. A
reference to another Technical Guidance Document
is a reference to the latest edition of a document
published by the Department of the Environment,
Heritage and Local Government under article 7 of
the Building Regulations 1997.
Diagrams are used in this document to illustrate
particular aspects of construction - they may not
show all the details of construction.
4
Conservation of Fuel and Energy
Building Regulations - The Requirement
The requirements regarding conservation of fuel and energy for dwellings are laid out in Part L of the Second
Schedule to the Building Regulations 1997 (S.I. No. 497 of 1997) as amended by the Building Regulations
(Amendment) Regulations 2007 (S.I. No. 854 of 2007).
The Second Schedule, insofar as it relates to works relating to dwellings, is amended to read as follows:
Conservation of Fuel and Energy
L1
L2
L3
A dwelling shall be designed and constructed so as to ensure that the energy performance of the
building is such as to limit the amount of energy required for the operation of the dwelling and the
amount of CO2 emissions associated with this energy use insofar as is reasonably practicable.
For new dwellings, the requirement of L1 shall be met by
a.
providing that the energy performance of the dwelling is such as to limit the calculated primary
energy consumption and related CO2 emissions insofar as is reasonably practicable, when both
energy consumption and CO2 emissions are calculated using the Dwelling Energy Assessment
Procedure (DEAP) published by Sustainable Energy Ireland;
b.
providing that, for new dwellings, a reasonable proportion of the energy consumption to meet the
energy performance of a dwelling is provided by renewable energy sources;
c.
limiting heat loss and, where appropriate, availing of heat gain through the fabric of the building;
d.
providing and commissioning energy efficient space and water heating systems with efficient heat
sources and effective controls;
e.
providing that all oil and gas fired boilers shall meet a minimum seasonal net efficiency of 86%;
f.
providing to the dwelling owner sufficient information about the building, the fixed building services
and their maintenance requirements so that the building can be operated in such a manner as to
use no more fuel and energy than is reasonable
All oil and gas fired boilers installed as replacements in existing dwellings shall meet a minimum seasonal
net efficiency of 86% where practicable.
5
Section 0: General Guidance
6
0.1:
Application of the Regulations
0.1.1 The aim of Part L of the Second Schedule to
the Building Regulations is to limit the use of fossil
fuel energy and related CO2 emissions arising from
the operation of buildings, while ensuring that
occupants can achieve adequate levels of lighting and
thermal comfort. Buildings should be designed and
constructed to achieve this aim as far as is
practicable.
This amendment of the Regulations amends
the requirements of Part L insofar as they
relate to dwellings and the guidance in this
Document applies to works to dwellings only.
This Document does not apply to works to
buildings other than dwellings, including
material alterations and material change of
use to such buildings. The 2006 edition of
TGD L continues to apply in these cases.
New Dwellings
0.1.2 For new dwellings, the key issues to be
addressed in order to ensure compliance are:
(a)
Primary Energy Consumption and related CO2
emissions: providing that the calculated
primary energy consumption associated with
the operation of the dwelling and the related
CO2 emissions, as described in Section 1.1, do
not exceed a target value specified in this
document
(b)
Use of Renewable Energy Sources: providing
that the contribution of low or zero carbon
energy sources to the calculated primary
energy requirement meets the target for such
contribution set down in Section 1.2
(c)
Fabric insulation: providing for fabric insulation,
including the limitation of cold bridging, which
satisfies the guidance in this regard set out in
Section 1.3 (Sub-sections 1.3.2 to 1.3.4)
(d)
Air Tightness: limiting air infiltration as set out
in Sub-section1.3.4
(e)
Boiler efficiency: providing an efficient boiler or
other heat source as set out in Sub-section
1.4.2
(f)
Building Services Controls: controlling, as
appropriate the demand for and output of
space heating and hot water services provided,
as set out in Sub-section 1.4.3
(g)
Insulation of Pipes, Ducts and Vessels: limiting
the heat loss from pipes, ducts and vessels
used for the transport or storage of heated
water or air, as set out in Sub-section 1.4.4
(h)
Mechanical Ventilation Systems: providing that,
where a mechanical ventilation system is
installed, the system meets reasonable
performance levels, as set out in Sub-section
1.4.5
(i)
Performance of Completed Dwelling: Ensure
design and construction process are such that
completed building satisfies compliance targets
and design intent. Guidance is given in Section
1.5
(j)
User information: Ensure that adequate
operating and maintenance instructions are
available to facilitate operation in an energy
efficient manner. Guidance is given in Section
1.6.
The principal aims of Part L of the Building
Regulations are to limit primary energy consumption
and associated CO 2 emissions. The performance
levels specified for items (b) to (i) above are in the
nature of backstop minimum performance levels so
as to ensure reasonable levels of performance for all
factors affecting energy use, irrespective of the
measures incorporated to achieve compliance with
Regulation L2(a). Meeting the performance levels
specified for items (b) to (i) will not necessarily mean
that the level specified for primar y energy
consumption and related CO2 emissions (item (a))
will be met. It is likely that one or more of the
performance levels specified, for items (b) to (i), will
need to be exceeded to achieve this.
0.1.3 This revision of Part L represents a significant
step towards the optimisation of the efficiency of
energy use in new dwellings and the minimisation of
related CO 2 emissions. It is intended that the
standards specified here will be tightened further in
2010. The aim is to achieve zero carbon emissions
associated with the operation and use of dwellings, at
the earliest date practicable.
7
0.1.4 Insofar as the current amendment does not
achieve this target, the design and construction of
dwellings complying with this amendment to Part L,
should be carried out in such a manner as to
facilitate, insofar as practicable, the future upgrading
of the building fabric and fixed services so as to
reduce further carbon emissions associated with the
operation and use of these dwellings.
0.1.5 Where a dwelling has an attached room or
space that is to be used for commercial purposes
(e.g. workshop, surgery, consulting room or office),
such room or space should be treated as part of the
dwelling if the commercial part could revert to
domestic use on a change of ownership, e.g. where
there is direct access between the commercial space
and the living accommodation, both are contained
within the same thermal envelope and the living
accommodation occupies a substantial proportion of
the total area of the building.
Where a new dwelling forms part of a larger
building, the guidance in this document applies to the
individual dwelling, and the relevant guidance in
Technical Guidance Document L- Conservation of
Fuel and Energy (May 2006 Edition) applies to the
non-dwelling parts of the building such as common
areas (including common areas of apartment blocks),
and in the case of mixed-use developments, the
commercial or retail space.
0.1.6 The guidance given in this Technical Guidance
Document is generally applicable to all works
associated with the construction of new dwellings.
However, unheated ancilliary areas which are not
intended for use as part of the habitable dwelling
area should generally be treated as outside the area
assessed in relation to energy consumption and CO2
emissions (see Section 1.1). However, where such
areas have the potential to become part of the
habitable area, e.g. attached garages, the external
fabric elements should comply with the guidance in
relation to fabric insulation given in Sub-sections
1.3.2 and 1.3.3.
An attached conservatory-style sunspace, or the like,
forming part of a new dwelling construction should
be treated as an integral part of the habitable area of
the dwelling.
8
Existing Dwellings
0.1.7 This amendment applies to all works to
existing dwellings that are covered by the
requirements of the Building Regulations, including
extensions, material alterations, material changes of
use and window and door replacement. In carrying
out this work, the aim should be to limit energy
requirements for the operation of the dwelling and
associated CO2 emissions as far as practicable as
required by Regulation L1. Specifically, Regulation L3
provides that replacement oil and gas boilers should
achieve a seasonal net efficiency of 86% where
practicable. The key issues to be addressed are:
(a)
Fabric insulation: providing reasonable levels of
fabric insulation in all new construction,
including, where provided, replacement
windows and doors. Guidance is given in Subsection 2.1.2
(b)
Air Tightness: limiting air infiltration through
the newly constructed elements as far as
practicable. Guidance is given in Sub-section
2.1.4
(c)
Boiler Efficiency: providing an efficient boiler
or other heat source as set out in Sub-section
2.2.2
(d)
Building Services Controls: where new space
and/or water heating services are provided,
controlling, as appropriate, the demand for and
output of these space heating and hot water
services. Guidance on appropriate measures is
given in Sub-section 2.2.3
(e)
Insulation of Pipes, Ducts and Vessels: limiting
the heat loss from pipes, ducts and vessels
used for the transport or storage of heated
water or air, as set out in Sub-section 2.2.4.
0.2 TECHNICAL RISKS AND
PRECAUTIONS
General
0.2.1 The incorporation of additional thickness of
thermal insulation and other energy conservation
measures can result in changes in traditional
construction practice. Care should be taken in design
and construction to ensure that these changes do
not increase the risk of certain types of problems,
such as rain penetration and condensation.
Some guidance on avoiding such increased risk is
given in Appendix B of this document. General
guidance on avoiding risks that may arise is also
contained in the publication “Thermal insulation:
avoiding risks; Building Research Establishment (Ref BR
262)”.
Guidance in relation to particular issues and
methods of construction will be found in relevant
standards.
Fire Safety
0.2.2 Part B of the Second Schedule to the
Building Regulations prescribes fire safety
requirements. In designing and constructing buildings
to comply with Part L, these requirements must be
met and the guidance in relation to fire safety in
TGD B should be fully taken into account. In
particular, it is important to ensure that windows,
which provide secondar y means of escape in
accordance with Section 1.5 of TGD B, comply with
the dimensional and other guidance for such
windows set out in Paragraph 1.5.6 of TGD B.
Ventilation
0.2.3 Part F of the Second Schedule to the Building
Regulations prescribes ventilation requirements both
to meet the needs of the occupants of the building
and to prevent excessive condensation in roofs and
roofspaces. A key aim of the provisions in relation to
ventilation of occupied spaces is to minimise the risk
of condensation, mould growth or other indoor air
quality problems. In addition to meeting the
requirements of Part F of the Building Regulations
the avoidance of excessive condensation requires
that appropriate heating and ventilation regimes be
employed in occupied dwellings. Advice for house
purchasers and occupants on these issues is
published separately by both HomeBond and
Sustainable Energy Ireland. It is the intention to
review TGD F to take account of the current
revision of Part L.
Part J of the Second Schedule to the Building
Regulations prescribes requirements in relation to
the supply of air for combustion appliances, including
open-flued appliances which draw air from the room
or space in which they are situated. TGD J provides
guidance in this regard.
0.3 THERMAL CONDUCTIVITY AND
THERMAL TRANSMITTANCE
0.3.1 Thermal conductivity (λ-value) relates to a
material or substance, and is a measure of the rate at
which heat passes through a uniform slab of unit
thickness of that material or substance, when unit
temperature difference is maintained between its
faces. It is expressed in units of Watts per metre per
degree (W/mK).
0.3.2 For the purpose of showing compliance with
this Part of the Building Regulations, design λ-values
based on manufacturers declared values should be
used. For thermally homogeneous materials, declared
and design values should be determined in
accordance with I.S. EN ISO 10456: 1997. Design
values for masonry materials should be determined
in accordance with I.S. EN 1745: 2002. For insulation
materials, values determined in accordance with the
appropriate harmonized European standard should
be used. Certified λ-values for foamed insulant
materials should take account of the blowing agent
actually used. The use of HCFC for this purpose is
no longer permitted.
For products or components for which no
appropriate standard exists, measured values,
certified by an approved body or certified laboratory
(see TGD D), should be used.
0.3.3 Tables A1 and A2 of Appendix A contain λ
values for some common building materials and
insulation materials. These are primarily based on
data contained in I.S. EN 12524: 2000 or in CIBSE
Guide A, Section A3. The values provide a general
indication of the thermal conductivity that may be
9
expected for these materials. In the absence of
declared values, design values or certified measured
values as outlined in Paragraph 0.3.2, values of
thermal conductivity given in Table A1 may be used.
However, values for specific products may differ from
these illustrative values. Indicative λ-values for
thermal insulation materials are given in Table A2.
These may be used at early design stage for the
purpose of assessing likely compliance with this Part
of the Regulations. However, compliance should be
verified using thermal conductivity values for these
materials derived as outlined in Paragraph 0.3.2
above.
0.3.4 Thermal transmittance (U-value) relates to a
building component or structure, and is a measure of
the rate at which heat passes through that
component or structure when unit temperature
difference is maintained between the ambient air
temperatures on each side. It is expressed in units of
Watts per square metre per degree of air
temperature difference (W/m2K).
0.3.5 Thermal transmittance values (U-values)
relevant to this Part of the Regulations are those
relating to elements exposed directly or indirectly to
the outside air. This includes floors directly in contact
with the ground, suspended ground floors
incorporating ventilated or unventilated voids, and
elements exposed indirectly via unheated spaces. The
U-value takes account of the effect of the ground,
voids and unheated spaces on the rate of heat loss,
where appropriate. Heat loss through elements that
separate dwellings or other premises that can
reasonably be assumed to be heated, is considered to
be negligible. Such elements do not need to meet any
particular U-value nor should they be taken into
account in calculation of CO2 emissions or overall
transmission heat loss.
0.3.6 A range of methods exists for calculating Uvalues of building elements. Methods of calculation
are outlined in Appendix A, together with examples
of their use. Alternatively U-values may be based on
certified measured values. Measurements of thermal
transmission properties of building components
generally should be made in accordance with I.S. EN
ISO 8990: 1997, or, in the case of windows and
doors, I.S. EN ISO 12567-1: 2001.
10
0.3.7 Any part of a roof that has a pitch of 70o or
more may be treated as a wall for the purpose of
assessing the appropriate level of thermal
transmission. Elements separating the building from
spaces that can reasonably be assumed to be heated
should not be included.
0.3.8 Appendix B contains tables of indicative Uvalues for certain common constructions. These are
derived using the calculation methods referred to in
Appendix A, and may be used in place of calculated
or measured values, where appropriate. These tables
provide a simple way to establish the U-value for a
given amount of insulation. Alternatively they may be
used to establish the amount of insulation needed to
achieve a given U-value. The values in the tables have
been derived taking account of typical repeated
thermal bridging where appropriate. Where an
element incorporates a non-repeating thermal
bridge, e.g. where the continuity of insulation is
broken or penetrated by material of reduced
insulating quality, the U-value derived from the table
should be adjusted to account for this thermal
bridge. Table B23 in Appendix B contains indicative
U-values for external doors, windows and rooflights
(roof windows).
0.4
DIMENSIONS
0.4.1 Except where otherwise indicated linear
measurements for the calculation of wall, roof and
floor areas and building volumes should be taken
between the finished internal faces of the
appropriate external building elements and, in the
case of roofs, in the plane of the insulation. Linear
measurements for the calculation of the areas of
external door, window and rooflight openings should
be taken between internal faces of appropriate cills,
lintels and reveals.
0.4.2 “Volume" means the total volume enclosed
by all enclosing elements and includes the volume of
non-usable spaces such as ducts, stairwells and floor
voids in intermediate floors.
0.5
DEFINITIONS
For the purposes of this Technical Guidance
Document the following definitions apply:
Note: Biomass (including biofuel) is generally included
in Delivered Energy and thus, together with the
energy used to produce and deliver it, included in
Primary Energy.
Energy Use (for a particular purpose e.g. space
heating, water heating, water heating, cooling,
ventilation, lighting): Energy input to the relevant
system to satisfy the relevant purpose.
Delivered Energy: Energy supplied to the dwelling and
its systems to satisfy the relevant energy uses e.g.
space heating, water heating, cooling, ventilation,
lighting. Delivered energy does not include
renewable energy produced on site.
Delivered energy differs from energy use by the
extent of on-site conversion and transformation
losses e.g. boiler efficiency losses
Primary Energy: Energy that has not been subjected to
any conversion or transformation process. For a
dwelling, it is the delivered energy plus the energy
used to produce the energy delivered to the
dwelling. It is calculated from the delivered energy,
with an allowance for any energy exported from the
site, using conversion factors.
Renewable Energy: Energy from renewable non-fossil
energy sources e.g. solar energy (thermal and
photovoltaic), wind, hydropower, biomass,
geothermal, wave, tidal, landfill gas, sewage treatment
plant gas and biogases.
Biomass: Biodegradable fraction of products, waste
and residues from agriculture (including vegetal and
animal substances), forestry and related industries, as
well as biodegradable fraction of industrial and
municipal waste, used as a fuel or energy source.
Fuels derived from biomass may be in solid, liquid or
gas form. In this document, where the term
“biomass” is used on it’s own, it should be taken to
mean solid biomass (wood, wood chip, wood pellet,
etc).
Biofuel: Liquid or gas fuel derived from biomass.
Seasonal Net Efficiency: The seasonal efficiency
calculated as defined in the DEAP manual.
11
Section 1: New Dwellings
12
1.1:
Limitation of Primary Energy Use and
CO2 Emissions
1.1.1 This Section provides guidance on how to
show compliance with the requirements in relation
to primary energy consumption and CO2 emissions
specified in Regulation L2(a). The methodology for
calculation to be used is specified in the Regulation
as the DEAP methodology. This methodology is
published by Sustainable Energy Ireland (SEI) and
calculates the energy consumption and CO 2
emissions associated with a standardised use of a
dwelling. The energy consumption is expressed in
terms of kilowatt hours per square metre floor area
per year (kWh/m 2 /yr) and the CO 2 emissions
expressed in terms of kilograms of CO2 per square
metre floor area per year (kg CO2/m2/yr). Full details
of the methodology are available on the SEI website
at http://www.sei.ie.
1.1.2 The performance criteria are based on the
relative values of the calculated primary energy
consumption and CO2 emissions of a dwelling being
assessed, and similar calculated values for a
Reference Dwelling. Details of the Reference
Dwelling are given in Appendix C. The criteria are
determined as follows:
-
Primar y energy consumption and CO 2
emissions for both the proposed dwelling and
the reference dwelling are calculated using
DEAP.
-
The calculated primary energy consumption of
the proposed dwelling is divided by that of the
reference dwelling, the result being the energy
performance coefficient (EPC) of the proposed
dwelling. To demonstrate that an acceptable
Primary Energy consumption rate has been
achieved, the calculated EPC of the dwelling
being assessed should be no greater than the
Maximum Permitted Energy Performance
Coefficient (MPEPC). The MPEPC is 0.6.
-
The calculated carbon dioxide emission rate of
the proposed dwelling is divided by that of the
reference dwelling, the result being the carbon
performance coefficient (CPC) of the
proposed dwelling. To demonstrate that an
acceptable Carbon Dioxide emission rate has
been achieved, the calculated CPC of the
dwelling being assessed should be no greater
than the Maximum Permitted Carbon
Performance Coefficient (MPCPC). The
MPCPC is 0.69.
The DEAP software will calculate the EPC and CPC
of the dwelling being assessed and clearly indicate
whether compliance with the requirements of
Regulation L2 (a) has been achieved.
1.1.3 Where a building contains more than one
dwelling (such as in a terrace of houses or a block of
apartments), reasonable provision would be to show
that:
-
every individual dwelling has an EPC and CPC
no greater than the MPEPC and MPCPC
respectively, or
-
the average EPC and CPC for all dwellings in
the building is no greater than the MPEPC and
MPCPC respectively.
Where the latter approach is used, the average EPC
and CPC are calculated by multiplying the EPC and
CPC for each individual dwelling by the floor area of
that dwelling, adding together and dividing the results
by the sum of the floor areas of all dwellings.
Common areas in the building are not included in
this calculation.
1.1.4
The requirements that the calculated EPC
and CPC do not exceed the calculated MPEPC and
MPCPC respectively, applies to the constructed
dwelling. Designers may wish to calculate the EPC
and CPC at early design stage in order to ensure
that the requirements can be achieved by the
constructed building. It is also open to professional
bodies or other industry interests to develop model
dwelling designs that can confidently be adopted
without the need to calculate the EPC and CPC at
design stage. However, the use of constructions and
service systems which have been assessed at design
stage, or other model designs, does not preclude the
need to verify compliance by calculating the EPC and
CPC when all relevant details of the final
construction are known.
1.1.5 The use of renewable and low carbon
technologies, such as solar hot water, biomass (e.g.
wood and wood pellets) and heat pumps, whether
provided to meet the requirements of this Part of
the Building Regulations (see Section 1.2) or
provided as additional to meeting that requirement,
can facilitate compliance with the requirements in
relation to primary energy use and CO2 emissions.
As defined, primary energy does not include energy
13
derived from on-site renewable energy technologies.
In addition, as renewable energy technologies
generally are characterised by zero, or greatly
reduced, CO2 emissions, the calculated EPC and CPC
are reduced by the extent that they replace
traditional fossil fuels. As the performance of the
Reference Dwelling (see Appendix C) is not affected
by the incorporation of these technologies in a
dwelling being assessed, this has the effect of making
it easier to achieve compliance with this Part of the
Building Regulations when these technologies are
used.
For certain dwelling types, use of renewables may
prove the most practical approach to achieving
compliance. The use of centralised renewable energy
sources contributing to a heat distribution system
serving all dwelling units in a development or
apartment block may prove to be more practicable
than providing separate renewable energy for each
dwelling individually.
14
1.2:
Renewable Energy Technologies
1.2.1 This section gives guidance on the minimum
level of renewable technologies to be provided to
sho compliance with Regulation L(2(b). The
following represents a reasonable minimum level of
energy provision from renewable energy
technologies in order to satisfy Regulation L2(b):
•
10 kWh/m2/annum contributing to energy use
for domestic hot water heating, space heating
or cooling, or
•
4 kWh/m2/annum of electrical energy, or
•
a combination of these which would have
equivalent effect.
For the purposes of this Section, “renewable energy
technologies” means technology, products or
equipment that supply energy derived from
renewable energy sources, e.g. solar thermal systems,
solar photo-voltaic systems, biomass systems,
systems using biofuels, heat pumps, aerogenerators
and other small scale renewable systems.
1.2.2 Where a building or development contains
more than one dwelling, reasonable provision would
be to show that:
-
every individual dwelling should meet the
minimum provision from renewable energy
technologies specified in Paragraph 1.2.1
above, or
-
the average contribution of renewable
technologies to all dwellings in the
building or development should meet that
minimum level of provision per dwelling.
Where the latter approach is used, common areas in
the building are not included in this calculation.
1.2.3 In the case of electrically powered heat
pumps, only energy in excess of 2.5 times the
electrical energy directly consumed by the heat
pump can be counted towards meeting the minimum
level of energy provision from renewable technology.
In the case of systems based on biofuels or biomass,
appliances must be designed to run on these fuels
only, i.e. incapable of providing thermal energy from
fossil fuels, to be accepted as renewable technology
for the purposes of this Regulation. For example a
boiler which could operate on either oil or a biofuel
mixture would not be considered to be a renewable
technology. Similarly a boiler capable of utilizing coal
or peat, in addition to a biomass fuel would not be
considered a renewable technology.
1.2.4 The use of centralised renewable energy
sources contributing to a heat distribution system
serving all dwelling units in a development or part of
a development, e.g. an apartment block, may prove to
be more practicable than providing separate
renewable energy for each dwelling individually.
1.2.5 As an alternative to providing
10kWh/m 2 /annum
thermal
energy
(or 4 kWh/m 2 /annum electrical energy) from
renewable technology sources, the use of a smallscale combined heat and power (CHP) system which
contributes to the space and water heating energy
use would be acceptable. This approach may be
appropriate in some high density developments, e.g.
apartment and mixed use developments.
1.2.6 Part D of the Building Regulations requires
that all works be carried out with proper materials
and in a workmanlike manner. “Materials” includes
products, components and items of equipment and
guidance is provided on how products, components
and items of equipment can be shown to be “proper
materials”. Renewable technologies should satisfy the
requirements of Part D in the same way as other
construction products and materials. A range of
standards applicable to renewable energy
technologies are given in the “Standards and Other
References” Section in this document. For specific
renewable technologies, it is intended that SEI will
maintain databases of acceptable products together
with information on relevant performance
characteristics. Products listed in these databases
may be assumed to be “proper materials” for the
purposes of this Part of the Building Regulations. It
is intended to establish databases for
-
Solar thermal systems
-
Wood pellet stoves
-
Wood pellet/chip boilers
-
Heat pumps.
15
1.2.7 To ensure that works are carried out in a
“workmanlike manner”, the design and installation of
renewable energy systems to comply with this
guidance should be carried out by a person qualified
to carry out such work.
16
1.3:
Building Fabric
1.3.1 GENERAL
1.3.1.1 This section gives guidance on acceptable
levels of provision to ensure that heat loss through
the fabric of a dwelling is limited insofar as
reasonably practicable. Guidance is given on three
main issues:
-
insulation levels to be achieved by the plane
fabric elements (Sub-section 1.3.2),
thermal bridging (Sub-section 1.3.3), and
limitation of air permeability (Sub-section
1.3.4).
1.3.1.2 Unheated areas which are wholly or largely
within the building structure, do not have permanent
ventilation openings and are not otherwise subject to
excessive air-infiltration or ventilation, e.g. common
areas such as stairwells, corridors in buildings
containing flats, may be considered as within the
insulated fabric. In that case, if the external fabric of
these areas is insulated to the same level as that
achieved by equivalent adjacent external elements, no
particular requirement for insulation between a
heated dwelling and unheated areas would arise. It
should be noted that heat losses to such unheated
areas are taken into account by the DEAP
methodology in the calculation of the dwelling EPC
and CPC (See Section 1.1).
1.3.2
FABRIC INSULATION
1.3.2.1 The derivation of U-values, including those
applicable where heat loss is to an unheated space, is
dealt with in Paragraphs 0.3.4 to 0.3.8 and Appendix
A.
1.3.2.2 In order to limit heat loss through the
building fabric reasonable provision should be made
to limit transmission heat loss by plane elements of
the building fabric. Acceptable levels of thermal
insulation for each of the plane elements of the
building to achieve this are specified in terms of
average area-weighted U-value (U m ) in Table 1
(Column 2) for each fabric element type. These
values can be relaxed for individual elements or parts
of elements where considered necessary for design
or construction reasons. Maximum acceptable values
for such elements or parts of elements are specified
in Column 3 of Table 1. Where this relaxation is
availed of, the average area-weighted values given in
Column 2 continue to apply and compensatory
insulation measures may be necessary for other
elements or parts of elements of that type to ensure
that these are met. Where the source of space
heating is underfloor heating, a floor U-value of 0.15
W/m 2K should generally be satisfactory. Further
guidance in relation to insulation of floors where
underfloor heating is proposed is contained in the
document “Heating and Domestic Hot Water Systems
for dwellings – Achieving compliance with Part L” (to be
published).
1.3.2.3 Reasonable provision would also be achieved
if the total heat loss through all the opaque elements
did not exceed that which would be the case if each
of the area-weighted average U-value (Um) set out in
Table 1 were achieved individually. Where this
approach is chosen, the values for individual elements
or sections of elements given in Table 1, (Column 3)
also apply. For ground floors or exposed floors
incorporating underfloor heating, the guidance in
Paragraph 1.3.2.2 applies.
Table 1
Maximum
(W/m2K)1,2
Column 1
Fabric Elements
Roofs
elemental U value
Column 2
Column 3
Area weighted Average Elemental
Average
U-value – individual
Elemental U- element or section
Value (Um)
of element
Pitched roof
- Insulation at ceiling
- Insulation on slope
0.16
0.20
Flat roof
0.22
Walls
Ground
Floors3
Other Exposed Floors3
External doors, windows
and rooflights
0.3
0.27
0.6
0.25
0.6
0.25
2.004
0.6
3.0
NOTES
1. The U-value includes the effect of unheated voids or other
spaces
2. For alternative method of showing compliance see
Paragraph 1.3.2.3
3. For insulation of ground floors and exposed floors
incorporating underfloor heating, see Paragraph 1.3.2.2
4. Windows, doors and rooflights should have maximum Uvalue of 2.0 W/m2K and maximum opening area of 25% of
floor area. However areas and U-values may be varied as
set out in Table 2
17
1.3.2.4 The maximum area-weighted average Uvalue for doors, windows and rooflights of 2.00
W/m2K given in Table 1 applies when the combined
area of external door, window and rooflight openings
does not exceed 25% of floor area. However, both
the permitted combined area of external door,
window and rooflight openings and the maximum
area-weighted average U-value of these elements
may be varied as set out in Table 2. The area of
openings should not be reduced below that required
for the provision of adequate daylight. BS 8206: Part
2: 1992 gives advice on adequate daylight provision.
Table 2
Permitted variation in combined
areas (A ope ) and average U-values
(Uope) of external doors, windows and
rooflights
Average U-value of
windows, doors and
rooflights (Uope)
(W/m2 K)
1.0
1.2
1.4
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.6
Maximum combined area of external
doors, windows and rooflights (Aope),
expressed as % of floor
area (Af)
59.2
46.5
38.3
32.5
30.2
28.3
26.5
25.0
22.4
22.4
21.3
20.3
18.6
NOTE : Intermediate values of “combined areas” or of “Uvalues” may be estimated by interpolation in the above Table.
Alternatively the following expression may be used to calculate
the appropriate value:
Aope/Af = 0.4325/(Uope - 0.27).
This expression may also be used to calculate appropriate
values outside the range covered by the Table.
1.3.2.5 Diagram 1 summarises the minimum fabric
insulation standards applicable.
18
Diagram 1
Average Area Weighted Elemental U-values
Para. 1.3.2.2
0.272
0.20
Unheated
attic
0.162
0.22
Average
U-value
2.01
0.27
0.25
Unheated space
NOTES
0.252
0.272
0.25
1. The average U-value of 2.0 W/m2K for windows, doors and rooflights applies when the area of these elements is equal
to 25% of floor area. Average U-value of these elements may vary as set out in Paragraph 1.3.2.4 and Table 2.
2
3
1.3.3
Average U-values of all elements may vary as set out in Paragraph 1.3.2.3
The U-values include the effect of unheated voids and other spaces.
THERMAL BRIDGING
(b)
Adopt details that are similar to, or
demonstrated as equivalent to, generic details
that have been assessed as limiting thermal
bridging to an equivalent level to that set out
in Table D1 of Appendix D. A set of such
details for typical constructions will be
developed in consultation with relevant
construction industry organisations and will be
made available in a document “Limiting Thermal
Bridging and Air Infiltration – Acceptable
Construction Details” (to be published).
Currently, the web document Accredited
Details downloadable from the Department of
Communities and Local Government (London)
website, www.communities.gov.uk contains a
significant number of such details. The
procedure for assessing the performance of
specific details is outlined in Appendix D. It is
also expected that further such details will be
made available by construction product
manufacturers in support of their products.
(c)
Use alternative details which limit the risk of
mould growth and surface condensation to an
acceptable level as set out in Paragraph D.2 of
Appendix D. The documents referred to in (b)
1.3.3.1 To avoid excessive heat losses and local
condensation problems, reasonable care should be
taken to ensure continuity of insulation and to limit
local thermal bridging, e.g. around windows, doors
and other wall openings, at junctions between
elements and other locations. Any thermal bridge
should not pose a risk of surface or interstitial
condensation. Heat loss associated with thermal
bridges is taken into account in calculating energy
use and CO 2 emissions using the DEAP
methodology. See Appendix D for further
information in relation to thermal bridging and it’s
effect on dwelling heat loss and how this is taken
account of in DEAP calculations.
1.3.3.2 The following represents alternative
approaches to making reasonable provision with
regard to limitation of thermal bridging:
(a)
Demonstrate by calculation in accordance
with the methodology outlined in Appendix D
that all key thermal bridges meet the
performance levels set out in Table D1 of
Appendix D.
19
above should not be considered as
representing an exhaustive list of acceptable
details, and designers and builders may employ
well-established details using other materials
that are equally suitable.
(b)
Develop appropriate details and performance
specification to ensure continuity of the air
barrier and communicate these to all those
involved in the construction process;
Irrespective of which approach is used, appropriate
provision for on-site inspection and related quality
control procedures should be made (See Subsections 1.5.2 and 1.5.3).
(c)
Provide on-site inspection regime and related
quality control procedures so as to ensure
that the design intention is achieved in
practice.
1.3.3.3 The DEAP calculation of primary energy
use and CO 2 emissions (see Section 1.1) takes
account of thermal bridging effects. In general this is
done by including an allowance for additional heat
loss due to thermal bridging, expressed as a
multiplier applied to the total exposed surface area.
Where provision for thermal bridging is made in
accordance with options (a) or (b) of Paragraph
1.3.3.2, this multiplier should be taken as 0.08. Where
option (c) of Paragraph 1.3.3.2 is used, it will be
necessar y to allow for each thermal bridge
separately in the calculation. Alternatively a multiplier
of 0.15 may be used.
1.3.4.3 Achievement of reasonable levels of air
permeability can be facilitated by adopting the
standard details referred to in Paragraph 1.3.3.2
above, together with an appropriate performance
specification and the on-site inspection regime and
related quality control procedures, referred to in that
paragraph. Alternative approaches to element design,
details and quality control procedures may also be
acceptable, provided it can be shown that these
approaches provide an equivalent level of
performance, as if the standard details, performance
specification and quality control procedures referred
to above were adopted.
Where details purporting to limit thermal bridging to
levels better than the level represented by Table D1
of Appendix D are used, i.e. a lower loss from
thermal bridging is used in the DEAP calculation than
that represented by using the 0.08 multiplier, the
details used should be fully specified and their
performance certified.
1.3.4.4 Air pressure testing should be carried out on
a proportion of dwellings on all development sites.
See Sub-section 1.5.4 for details of the test
procedure, extent of testing, use of test results in
DEAP calculations and appropriate measures to be
undertaken where the limit set is not achieved.
When tested in accordance with the procedure
referred to in Sub-section 1.5.4, a performance level
of 10m3/(h.m2) represents a reasonable upper limit
for air permeability.
1.3.4
BUILDING
PERMEABILITY
ENVELOPE
AIR
1.3.4.1 To avoid excessive heat losses, reasonable
care should be taken to limit the air permeability of
the envelope of each dwelling. In this context,
envelope is the total area of all floors, walls (including
windows and doors), and ceilings bordering the
dwelling, including elements adjoining other heated
or unheated spaces.
1.3.4.2 The following represents a reasonable
approach to the design of dwellings to ensure
acceptable levels of air permeability:
(a)
20
Identify the primary air barrier elements (e,g,
sheathing, plaster, vapour control layer,
breather paper) at early design stage;
1.4:
1.4.1
Building Services
GENERAL
1.4.1.1 Regulation L2 (d) requires that space and
water heating systems in dwellings be energy
efficient, with efficient heat sources and effective
controls. More specifically Regulation L2 (e) provides
that oil or gas fired boilers must achieve a minimum
seasonal net efficiency of 86%. This Section gives
guidance for dwellings where the main space and
water heating is based on pumped low temperature
hot water systems, utilising radiators for space
heating and incorporating a hot water cylinder for
the storage of domestic hot water, and the fuel used
is natural gas, LPG or oil. Guidance is given on three
main issues:
(a)
(b)
(c)
Heating appliance efficiency (Sub-section
1.4.2),
Space Heating and Hot Water Supply System
Controls (Sub-section 1.4.3), and
Insulation of Hot Water Storage Vessels, Pipes
and Ducts (Sub-section 1,4.4)
Detailed guidance for dwellings using a wide range of
space and water heating systems is contained in a
supporting document “Heating and Domestic Hot
Water Systems for dwellings – Achieving compliance with
Part L” (to be published).
1.4.1.2 This Section also contains guidance in
relation to the energy efficiency aspects of
mechanical ventilation systems, where provided (Subsection 1.4.5).
1.4.2 HEATING APPLIANCE EFFICIENCY
1.4.2.1 The appliance or appliances provided to
service space heating and hot water systems should
be as efficient in use as reasonably practicable. For
fully pumped hot water based central heating
systems utilizing oil or gas, the boiler seasonal
efficiency should be not less than 86% as specified in
the DEAP manual and the associated Home-heating
Appliance Register of Performance (HARP) database
maintained by SEI (www.sei.ie/harp).
1.4.3 SPACE HEATING AND HOT WATER
SUPPLY SYSTEM CONTROLS
1.4.3.1 Space and water heating systems should be
effectively controlled so as to ensure the efficient use
of energy by limiting the provision of heat energy use
to that required to satisfy user requirements, insofar
as reasonably practicable. The aim should be to
provide the following minimum level of control:
•
automatic control of space heating on basis of
room temperature;
•
automatic control of heat input to stored hot
water on basis of stored water temperature;
•
separate and independent automatic time
control of space heating and hot water;
•
shut down of boiler or other heat source
when there is no demand for either space or
water heating from that source.
The guidance in Paragraphs 1.4.3.2 to 1.4.3.5 below
is specifically applicable to fully pumped hot water
based central heating systems.
1.4.3.2 Provision should be made to control heat
input on the basis of temperature within the heated
space, e.g. by the use of room thermostats,
thermostatic radiator valves, or other equivalent
form of sensing device. For larger dwellings,
independent temperature control should generally
be provided for separate zones that normally
operate at different temperatures, e.g. living and
sleeping zones. Thermostats should be located in a
position representative of the temperature in the
area being controlled and which is not unduly
influenced by draughts, direct sunlight or other
factors which would directly affect performance.
Depending on the design and layout of the dwelling,
control on the basis of a single zone will generally be
satisfactor y for smaller dwellings. For larger
dwellings, e.g. where floor area exceeds 100 m2,
independent temperature control on the basis of
two independent zones will generally be appropriate.
In certain cases additional zone control may be
desirable, e.g. zones which experience significant
solar or other energy inputs may be controlled
separately from zones not experiencing such inputs.
1.4.3.3 Hot water storage vessels should be fitted
with thermostatic control that shuts off the supply of
heat when the desired storage temperature is
reached.
1.4.3.4 Separate and independent time control for
space heating and for heating of stored water should
21
be provided. Independent time control of space
heating zones may be appropriate where
independent temperature control applies, but is not
generally necessary.
1.4.3.5 The operation of controls should be such
that the boiler is switched off when no heat is
required for either space or water heating. Systems
controlled by thermostatic radiator valves should be
fitted with flow control or other equivalent device to
ensure boiler switch off.
1.4.4 INSULATION OF HOT WATER
STORAGE VESSELS, PIPES AND DUCTS
1.4.4.1 All hot water storage vessels, pipes and ducts
associated with the provision of heating and hot
water in a dwelling should be insulated to prevent
heat loss except for hot water pipes and ducts within
the normally heated area of the dwelling that
contribute to the heat requirement of the dwelling.
Pipes and ducts which are incorporated into wall,
floor or roof construction should be insulated.
1.4.4.2 Adequate insulation of hot water storage
vessels can be achieved by the use of a storage vessel
with factory-applied insulation of such characteristics
that, when tested on a 120 litre cylinder complying
with I.S. 161: 1975 using the method specified in
BS1566, Part 1: 2002, Appendix B, standing heat
losses are restricted to 0.8 W/litre. Use of a storage
vessel with 50 mm, factory-applied coating of PUfoam having zero ozone depletion potential and a
minimum density of 30 kg/m3 satisfies this criterion.
Alternative insulation measures giving equivalent
performance may also be used.
1.4.4.3 Unless the heat loss from a pipe or duct
carrying hot water contributes to the useful heat
requirement of a room or space, the pipe or duct
should be insulated. The following levels of insulation
should suffice:
(a)
(b)
22
pipe or duct insulation meeting the
recommendations of BS 5422: 2001 Methods of
specifying thermal insulating materials for pipes,
ductwork and equipment (in the temperature
range - 400oC to + 700oC), or
insulation with material of such thickness as
gives an equivalent reduction in heat loss as
that achieved using material having a thermal
conductivity at 400oC of 0.035 W/mK and a
thickness equal to the outside diameter of the
pipe, for pipes up to 40 mm diameter, and a
thickness of 40 mm for larger pipes.
1.4.4.4 The hot pipes connected to hot water
storage vessels, including the vent pipe and the
primary flow and return to the heat exchanger,
where fitted, should be insulated, to the standard
outlined in Paragraph 1.4.4.3 above, for at least one
metre from their point of connection.
1.4.4.5 It should be noted that water pipes and
storage vessels in unheated areas will generally need
to be insulated for the purpose of protection against
freezing. Guidance on suitable protection measures is
given in Report BR 262, Thermal insulation: avoiding
risks published by BRE.
1.4.5
MECHANICAL
SYSTEMS
VENTILATION
1.4.5.1 Guidance on good practice with regard to
energy efficiency of dwelling ventilation systems is
contained in GPG 268 Energy efficient ventilation in
dwellings – a guide for specifiers, available from SEI.
1.4.5.2 Where a mechanical ventilation system
designed for continuous operation (with or without
heat recovery) is installed for the provision of
ventilation to a dwelling or significant part thereof,
the system should meet the performance levels
specified in GPG 268 and also have specific fan
power and heat recover y efficiency (where
appropriate) not worse than those given in Table 3.
Significantly better standards in relation to air
permeability than those specified in Paragraph 1.3.4.3
are desirable in dwellings with mechanical ventilation,
especially ventilation systems with heat recovery.
Table 3 does not apply to fans installed for
intermittent use in individual rooms.
Table 3
Minimum performance levels for
mechanical ventilation systems
System type
Performance
Specific Fan Power (SFP) for
continuous supply only and
continuous extract only
0.8 W/litre/sec
Heat recovery efficiency
66%
SFP for balanced systems
2.0 W/litre/sec
1.5:
1.5.1
Construction Quality and
Commissioning of Services
GENERAL
1.5.1.1 The requirements of Part L apply to the
completed building. Reasonable measures should be
taken during construction and appropriate checks
and assessments carried out prior to completion to
ensure that compliance with Part L is achieved. Subsections 1.5.2 to 1.5.4 give guidance on appropriate
measures to satisfy this requirement.
1.5.2 INSULATION CONTINUITY AND
AIR PERMEABILITY
1.5.2.1 The elements that comprise the external
fabric of the building should be designed and
constructed to ensure that the calculated
performance of the building and of its components is
achieved in practice. Changes made during design and
construction should be assessed for their impact on
insulation performance and on air permeability.
Those not directly involved in the installation of
insulation should be fully aware of the importance of
not reducing the effectiveness of the installed
insulation through removal or damage. On-site
quality control should include checks on the
adequacy of insulation installation and of any barriers
designed to limit air permeability, including an
inspection of finished work to ensure that all work is
properly constructed before covering over.
1.5.3
THERMAL BRIDGING
1.5.3.1 There should be no reasonably avoidable
thermal bridging, e.g. due to gaps between insulation
layers and at joints, junctions and edges around
openings. Where unavoidable thermal bridging is
provided for in the design, care should be taken to
ensure that the chosen design detail is accurately
constructed on site.
1.5.4 AIR PERMEABILITY PRESSURE
TESTS
1.5.4.1 Air permeability can be measured by means
of pressure testing of a building prior to completion.
The procedure for testing is specified in IS EN
13829:2000 “Thermal performance of buildings:
determination of air permeability of buildings: fan
pressurization method”. Additional guidance on testing
procedure is given in Sections 2 to 4 of the BSRIA
Guide “Airtightness testing for new dwellings” and
CIBSE Technical Manual TM 23 “Testing Buildings for
Air leakage”. Permeability is calculated by dividing the
air leakage rate in m3/hr by the envelope area in m2
The performance is assessed at 50 Pascals pressure
difference. It has been empirically determined that
for dwellings generally the permeability at 50 Pascals
pressure difference is approximately 20 times the air
change rate at normal conditions. Guidance on
appropriate extent of testing is given in Paragraph
1.5.4.3.
1.5.4.2 Subject to the guidance in Paragraph
1.5.4.7, air pressure testing should be carried out on
a proportion of dwellings on all development sites, as
outlined in Paragraphs 1.5.4.3 to 1.5.4.6. The tests
should be carried out by a person competent to
carry out this work. The test report should contain
at least the information specified in Section 7 of IS
EN 13829.
1.5.4.3 On each development, an air pressure test
should be carried out on at least one unit of each
dwelling type. One dwelling from the first four units
of each dwelling type planned for completion should
be tested. The basic number of tests for each
dwelling type is presented in Table 4. The total
number tested is related to the number of units of
that type in the development and to the results
achieved in any earlier tests carried out. Where a
number of apartment blocks are constructed on the
same site, each block should be treated as a separate
development irrespective of the number of blocks on
the site.
Table 4
Number of pressure tests per
dwelling type
Number of units
4 or less
Number of tests
One test
Greater than 4, but equal or less Two tests
than 40
Greater than 40, but equal or less At least 5% of the dwelling
than 100
type
More than 100
(a)
(b)
where the first five tests
achieve the design air
permeability
where one or more of first
five tests do not achieve
the design air permeability
At least 2% (for dwellings
in excess of first 100 units)
At least 5% of units, until 5
successful consecutive tests
are achieved, 2% thereafter
23
1.5.4.4 If the measured air change rates are not
worse than the criterion set out in Paragraph 1.3.4.3,
the test results should be taken as satisfactory
evidence that the requirements of Part L2 (c), insofar
as it relates to air tightness, has been demonstrated
for this dwelling type. If satisfactory performance is
not achieved in a particular test, then remedial
measures should be carried out on the test dwelling
and a new test carried out. This should be repeated
until the dwelling achieves the criterion set out in
Paragraph 1.3.4.3. Dwellings completed later than the
most recent successful test on a dwelling of this type
should either have similar remedial work carried out
or should be subject to pressure test.
1.5.4.5 Where remedial work and a new test is
required on any dwelling following initial test, the size
of sample for testing should be increased by one, for
that dwelling type.
1.5.4.6 Where the air permeability assumed for
the DEAP calculations is better than the value
derived from pressure test results, a check
calculation should be carried out to show that the
calculated EPC and CPC using the measured air
permeability (after any remedial works to satisfy
Paragraph 1.3.4.3, if such are necessary) are not
worse than the MPEPC and MPCPC respectively. If
necessary, additional remedial works or other
measures should be carried out to ensure that this
criterion is also met. Where further remedial works
to reduce air permeability are undertaken, a further
test would be necessar y to verify revised air
permeability figure to be used in revised DEAP
calculations.
1.5.4.7 For small developments comprising no
more than three dwelling units, specific pressure
testing of these dwellings would not be necessary if it
can be demonstrated with air pressure test reports
that, during the preceding 12 month period, a
dwelling of the same dwelling type constructed by
the same builder had been pressure tested according
to the procedures given in this sub-section and had
satisfied the criterion set in Paragraph 1.3.4.3.
However, if the assumed air change rate in the
calculation of the EPC and CPC using the DEAP
methodology is less than the criterion set in
Paragraph 1.3.4.3, a pressure test to verify this
assumed value should be carried out. The guidance
given in this sub-section would apply in this situation.
24
1.5.4.8 Air pressurisation test reports should be
retained by the developer of the dwelling as proof of
performance, and copies included in the User
Information referred to in Section 1.6.
1.5.5 COMMISSIONING SPACE
WATER HEATING SYSTEMS
AND
1.5.5.1 The heating and hot water system(s) should
be commissioned so that at completion, the
system(s) and their controls are left in the intended
working order and can operate efficiently for the
purposes of the conservation of fuel and power. The
procedure for carrying out commissioning of these
systems is set out in Heating and Domestic Hot Water
Systems for Dwellings – Achieving compliance with Part L
(to be published).
1.6:
User Information
1.6.1. The owner of the building should be provided
with sufficient information about the building, the
fixed building ser vices and their maintenance
requirements so that the building can be operated in
such a manner as to use no more fuel and energy
than is reasonable in the circumstances. A way of
complying would be to provide a suitable set of
operating and maintenance instructions aimed at
achieving economy in the use of fuel and energy in a
way that householders can understand. The
instructions should be directly related to the
particular system(s) installed in the dwelling. Without
prejudice to the need to comply with health and
safety requirements, the instructions should explain
to the occupier of the dwelling how to operate the
system(s) efficiently. This should include
(a)
the making of adjustments to the timing and
temperature control settings, and
(b)
what routine maintenance is needed to enable
operating efficiency to be maintained at a
reasonable level through the service live(s) of
the system(s).
The information to satisfy this requirement may be
provided in the context of the Advisory Report to
the mandatory Building Energy Rating certificate,
augmented as appropriate.
25
Section 2: Existing Dwellings
26
2.1:
2.1.1
Building Fabric
GENERAL
2.1.1.1 This section gives guidance on acceptable
levels of provision to ensure that heat loss through
fabric elements provided by way of material
alteration or extension to an existing dwelling is
limited insofar as reasonably practicable. Guidance is
given on three main issues:
-
insulation levels to be achieved by the plane
fabric elements (Sub-section 2.1.2),
-
thermal bridging (Sub-section 2.1.3), and
-
limitation of air permeability (Sub-section
2.1.4).
Where a material change of use of an existing
building to use as a dwelling occurs, the performance
of the fabric elements of the newly provided dwelling
should also meet the performance levels specified in
this Sub-section.
2.1.1.2 This Part of the Building Regulations applies
to the replacement of external doors, windows, or
rooflights in an existing building. The average Uvalue of replacement units should not exceed the
value of 2.0 W/m 2 K set out in Table 5. In this
context, the repair or renewal of parts of individual
elements, e.g. window glass, window casement sash,
door leaf, should be considered as repair and not
replacement.
2.1.1.3 Unheated areas which are wholly or largely
within the building structure, do not have permanent
ventilation openings and are not otherwise subject to
excessive air-infiltration or ventilation, e.g. common
areas such as stairwells, corridors in buildings
containing flats, may be considered as within the
insulated fabric. In that case, if the external fabric of
these areas is insulated to the same level as that
achieved by equivalent adjacent external elements, no
particular requirement for insulation between a
heated dwelling and unheated areas would arise.
2.1.2
2.1.2.2 Acceptable levels of thermal insulation for
each of the plane elements of the building are
specified in terms of average area-weighted U-value
(Um) in Table 5 for each fabric element type for
extensions (Column 2) and for material alterations
and material changes of use (Column 3). These
values can be relaxed for individual elements or parts
of elements where considered necessary for design
or construction reasons. Where this relaxation is
availed of, the average area-weighted values given in
Table 5 continue to apply and compensator y
insulation measures may be necessary for other
elements or parts of elements of that type to ensure
that these are met. Where the source of space
heating is underfloor heating, a floor U-value of 0.15
W/m 2K should generally be satisfactory. Further
guidance in relation to insulation of floors where
underfloor heating is proposed is contained in the
document “Heating and Domestic Hot Water Systems
for dwellings – Achieving compliance with Part L” (to be
published).
2.1.2.3 For extensions, reasonable provision would
also be achieved if the total heat loss through all the
opaque elements did not exceed that which would
be the case if each of the area-weighted average Uvalue (Um) set out in Table 5 were achieved
individually. Where this approach is chosen, the
values for individual elements or sections of
elements given in Table 5, Column 3 apply to each
relevant element. For ground floors or exposed
floors incorporating underfloor heating, the guidance
in Paragraph 2.1.2.2 applies.
FABRIC INSULATION
2.1.2.1 The derivation of U-values, including those
applicable where heat loss is to an unheated space, is
dealt with in Paragraphs 0.3.4 to 0.3.8 and Appendix
A.
27
Table 5
Maximum average area-weighted
elemental U-value (W/m2K)1,2
Column 1
Fabric Elements
Column 2
Extensions
Column 3
Material Alterations
or Material Change
of Use
Pitched roof
- Insulation at ceiling
- Insulation on slope
0.16
0.20
0.35
Flat roof
0.22
Ground Floors3
0.25
Roofs
Walls
Other Exposed Floors3
External doors, windows
and rooflights
0.27
0.60
0.25
0.60
2.004
-
2.004
NOTES
1. The U-value includes the effect of unheated voids or other
spaces
2. For material alterations, the U-values relate to the new
works
3. For insulation of ground floors and exposed floors
incorporating underfloor heating, see Paragraph 2.1.2.2
4. For extensions and material change of use, windows, doors
and rooflights should have maximum U-value of 2.0 W/m2K
and maximum opening area of 25% of floor area. However
areas and U-values may be varied as set out in Table 6 and
Paragraph 2.1.2.4
2.1.2.4 For extensions, the maximum area-weighted
average U-value for doors, windows and rooflights of
2.00 W/m 2 K given in Table 5 applies when the
combined area of external door, window and
rooflight openings does not exceed 25% of floor
area. However, both the permitted combined area of
external door, window and rooflight openings and
the maximum area-weighted average U-value of
these elements may be varied as set out in Table 6.
The area of openings should not be reduced below
that required for the provision of adequate daylight.
BS 8206: Part 2: 1992 gives advice on adequate
daylight provision.
2.1.2.5 In applying Paragraph 2.1.2.4 to an extension
to an existing dwelling, the relevant floor area may be
taken to be:
28
(a)
the combined floor area of the existing
dwelling and extension; in this case the
combined area of external doors, windows and
rooflight openings refers to the area of such
openings in the extended dwelling, i.e. the
opening area of retained external doors,
windows and rooflights together with the
opening area of external doors, windows and
rooflights in the extension; or
(b)
the floor area of the extension alone; in this
case the combined area of external doors,
window and rooflight openings refers to the
area of such openings in the extension alone.
In this case, the maximum combined area of
external doors, windows and rooflights
derived using Table 6 can be increased by an
area equivalent to the area of external door;
window and rooflight openings of the existing
dwellings which have been closed or covered
over by the extension.
For extensions which
-
are thermally separated from the
adjacent spaces within the building by
walls, doors and other opaque or glazed
elements which have U-values not more
than 10% greater than corresponding
exposed areas of the main dwelling, and
-
are unheated or, if provided with a
heating facility, have provision for
automatic temperature and on-off
control independent of the heating
provision in the existing building,
the limitation on the combined area of exposed
external door, window and rooflight openings does
not apply. In this case the average U-value of these
elements should not exceed the value of 2.0 W/m2K.
2.1.2.6 This Part of the Building Regulations applies
to the replacement of external doors, windows, or
rooflights in an existing dwelling. The average Uvalue of replacement units should not exceed the
value of 2.0 W/m 2 K set out in Table 5. In this
context, the repair or renewal of parts of individual
elements, e.g. window glass, window casement sash,
door leaf should be considered as repair and not
replacement.
Table 6
Permitted variation in combined
areas (A ope ) and average U-values
(Uope ) of external doors, windows and
rooflights
Average U-value of windows,
doors and rooflights (Uope)
(W/m2 K)
Maximum combined area of
external doors, windows and
rooflights (Aope), expressed as
% of floor area (Af)
1.0
1.2
1.4
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.6
59.2
46.5
38.3
32.5
30.2
28.3
26.5
25.0
22.4
22.4
21.3
20.3
18.6
NOTE : Intermediate values of “combined areas” or of “Uvalues” may be estimated by interpolation in the above Table.
Alternatively the following expression may be used to calculate
the appropriate value:
Aope/Af = 0.4325/(Uope - 0.27).
This expression may also be used to calculate appropriate values
outside the range covered by the Table.
2.1.3
THERMAL BRIDGING
2.1.3.1 To avoid excessive heat losses and local
condensation problems, reasonable care should be
taken to ensure continuity of insulation and to limit
local thermal bridging, e.g. around windows, doors
and other wall openings, at junctions between
elements and other locations. Any thermal bridge
should not pose a risk of surface or interstitial
condensation. See Appendix D for further
information in relation to thermal bridging and it’s
effect on dwelling heat loss.
2.1.3.2 The following represents alternative
approaches to making reasonable provision with
regard to limitation of thermal bridging
-
performance levels set out in Table D1 of
Appendix D.
-
Adopt details that are similar to, or
demonstrated as equivalent to, generic details
that have been assessed as limiting thermal
bridging to an equivalent level to that set out
in Table D1 of Appendix D. A set of such
details for typical constructions will be
developed in consultation with relevant
construction industry organisations and will be
made available in a document “Limiting Thermal
Bridging and Air Infiltration – Acceptable
Construction Details” (to be published).
Currently, the web document Accredited
Details downloadable from the Department of
Communities and Local Government (London)
website www.communities.gov.uk contains a
significant number of such details.
2.1.3.3 Lintel, jamb and cill designs similar to those
shown in Diagram 2 would be satisfactory and heat
losses due to thermal bridging can be ignored if they
are adopted. At lintel, jambs and cills generally a 15
mm thickness of insulation material having λ-value of
0.04 W/mK (or equivalent) will generally be
adequate.
2.1.3.4 Care should be taken to control the risk of
thermal bridging at the edges of floors. All slab-onground floors should be provided with edge
insulation to the vertical edge of the slab at all
external and internal walls. The insulation should
have minimum thermal resistance of 0.7 m2K/W (25
mm of insulation with thermal conductivity of 0.035
W/mK, or equivalent). Some large floors may have
an acceptable average U-value without the need for
added insulation. However, perimeter insulation
should always be provided. Perimeter insulation
should extend at least 0.5m vertically or 1m
horizontally. Where the perimeter insulation is
placed horizontally, insulation to the vertical edge of
the slab should also be provided as indicated above.
Demonstrate by calculation in accordance
with the methodology outlined in Appendix D
that all key thermal bridges meet the
29
Diagram 2
Lintel, jamb and cill designs
Para 2.1.3.3
LINTELS
JAMBS
CILLS
HEAT LOSS PATHS
without insulation
INTERNAL INSULATION
PARTIAL CAVITY FILL
FULL CAVITY FILL
NOTE
1.
30
The internal faces of metal lintels should be covered with at least 15 mm of lightweight plaster; alternatively
they can be dry-lined.
2.1.4
AIR PERMEABILITY
2.1.4.1 Infiltration of cold outside air should be
limited by reducing unintentional air paths as far as is
practicable. Measures to ensure this include:
(a)
sealing the void between dry-lining and
masonry walls at the edges of openings such as
windows and doors, and at the junctions with
walls, floors and ceilings (e.g. by continuous
bands of bonding plaster or battens),
(b)
sealing vapour control membranes in timberframe constructions,
(c)
fitting draught-stripping in the frames of
openable elements of windows, doors and
rooflights,
(d)
sealing around loft hatches,
(e)
ensuring boxing for concealed services is
sealed at floor and ceiling levels and sealing
piped services where they penetrate or
project into hollow construcionts or voids.
Diagram 3 illustrates some of these measures.
Care should be taken to ensure compliance with the
ventilation requirements of Part F and Part J.
Diagram 3
Air infiltration measures
Para 2.1.4.1
Seal at perimeter
Continuous seals
(bonding plaster,
battens or similar)
Draught seal
1.
POSITION OF CONTINUOUS SEALING BANDS FOR
DRY-LININGS FIXED TO MASONRY WALLS
2.
Bolt or catch to compress
draught seal
3.
SEALING ACCESS HATCH
Draught seal
SEALING AT WINDOWS AND DOORS
Seals
Close fitting
hole in
plasterboard
4.
Ceiling
SEALING AROUND SERVICE PIPES
31
2.2:
Building Services
2.2.1 GENERAL
2.2.1.1 Space and water heating systems provided
in the context of material alterations to existing
dwellings or extensions to existing dwellings should
be energy efficient and have efficient heat sources
and effective controls. Similar considerations apply to
space and water heating systems provided in the
context of a material change of use of an existing
building to use as a dwelling. Specifically, Regulation
L3 provides that oil or gas fired boilers installed as
replacements in existing dwellings should have a
minimum seasonal net efficiency of 86%, where
practicable.
This Section gives guidance where the main space
and water heating is based on pumped low
temperature hot water systems, utilising radiators for
space heating and incorporating a hot water cylinder
for the storage of domestic hot water, and the fuel
used is natural gas, LPG or oil. Guidance is given on
three main issues:
(a)
Heating appliance efficiency (Sub-section
2.2.2),
(b)
Space Heating and Hot Water Supply System
Controls (Sub-section 2.2.3), and
(c)
Insulation of Hot Water Storage Vessels, Pipes
and Ducts (Sub-section 2.2.4)
Detailed guidance for dwellings using a wide range of
space and water heating systems is contained in a
supporting document “Heating and Domestic Hot
Water Systems for dwellings – Achieving compliance with
Part L” (to be published).
2.2.2
HEATING APPLIANCE EFFICIENCY
2.2.2.1 The appliance or appliances provided to
service space heating and hot water systems should
be as efficient in use as reasonably practicable.
Guidance on appropriate efficiency for various
systems and fuels is contained in “Heating and
Domestic Hot Water Systems for dwellings – Achieving
compliance with Part L” (to be published). For fully
pumped hot water based central heating systems
utilizing oil or gas, the boiler seasonal efficiency
should be not less than 86% as specified in the DEAP
32
manual and the associated Home-heating Appliance
Register of Performance (HARP) database
maintained by SEI (www.sei.ie/harp). Effectively this
requires the use of condensing boilers. In a limited
number of situations involving replacement of
existing boilers, provision of a condensing boiler may
not be practicable. Detailed guidance on the
assessment of specific situations to identify those
where provision of condensing boilers is not
practicable is given in “Heating and Domestic Hot
Water Systems for dwellings – Achieving compliance with
Part L” (to be published)
2.2.3 SPACE HEATING AND HOT WATER
SUPPLY SYSTEM CONTROLS
2.2.3.1 Space and water heating systems should be
effectively controlled so as to ensure the efficient use
of energy by limiting the provision of heat energy use
to that required to satisfy user requirements, insofar
as reasonably practicable. The aim should be to
provide the following minimum level of control:
•
automatic control of space heating on basis of
room temperature;
•
automatic control of heat input to stored hot
water on basis of stored water temperature;
•
separate and independent automatic time
control of space heating and hot water;
•
shut down of boiler or other heat source
when there is no demand for either space or
water heating from that source.
The guidance in Paragraphs 2.2.3.2 to 2.2.3.5 below
is specifically applicable to fully pumped hot water
based central heating systems.
2.2.3.2 Provision should be made to control heat
input on the basis of temperature within the heated
space, e.g. by the use of room thermostats,
thermostatic radiator valves, or other equivalent
form of sensing device. For larger dwellings,
independent temperature control should generally
be provided for separate zones that normally
operate at different temperatures, e.g. living and
sleeping zones. Thermostats should be located in a
position representative of the temperature in the
area being controlled and which is not unduly
influenced by draughts, direct sunlight or other
factors which would directly affect performance.
Depending on the design and layout of the dwelling,
control on the basis of a single zone will generally be
satisfactor y for smaller dwellings. For larger
dwellings,e.g. where floor area exceeds 100 m 2,
independent temperature control on the basis of
two independent zones will generally be appropriate.
In certain cases additional zone control may be
desirable, e.g. zones which experience significant
solar or other energy inputs may be controlled
separately from zones not experiencing such inputs.
2.2.3.3 Hot water storage vessels should be fitted
with thermostatic control that shuts off the supply of
heat when the desired storage temperature is
reached.
2.2.3.4 Separate and independent time control for
space heating and for heating of stored water should
be provided. Independent time control of space
heating zones may be appropriate where
independent temperature control applies, but is not
generally necessary.
2.2.3.5 The operation of controls should be such
that the boiler is switched off when no heat is
required for either space or water heating. Systems
controlled by thermostatic radiator valves should be
fitted with flow control or other equivalent device to
ensure boiler switch off.
2.2.4 INSULATION OF HOT WATER
STORAGE VESSELS, PIPES AND DUCTS
2.2.4.1 Hot water storage vessels, pipes and ducts
associated with the provision of space heating and
hot water in a dwelling should be insulated to
prevent heat loss except for hot water pipes and
ducts within the normally heated area of the dwelling
that contribute to the heat requirement of the
dwelling. Pipes and ducts which are incorporated into
wall, floor or roof construction should be insulated.
vessel with 50 mm, factory-applied coating of PUfoam having zero ozone depletion potential and a
minimum density of 30 kg/m3 satisfies this criterion.
Alternative insulation measures giving equivalent
performance may also be used.
2.2.4.3 Unless the heat loss from a pipe or duct
carrying hot water contributes to the useful heat
requirement of a room or space, the pipe or duct
should be insulated. The following levels of insulation
should suffice:
(a)
pipe or duct insulation meeting the
recommendations of BS 5422: 2001 Methods of
specifying thermal insulating materials for pipes,
ductwork and equipment (in the temperature
range - 400oC to + 700oC), or
(b)
insulation with material of such thickness as
gives an equivalent reduction in heat loss as
that achieved using material having a thermal
conductivity at 400oC of 0.035 W/mK and a
thickness equal to the outside diameter of the
pipe, for pipes up to 40 mm diameter, and a
thickness of 40 mm for larger pipes.
2.2.4.4 The hot pipes connected to hot water
storage vessels, including the vent pipe and the
primary flow and return to the heat exchanger,
where fitted, should be insulated, to the standard
outlined in Paragraph 2.2.4.3 above, for at least one
metre from their point of connection.
2.2.4.5 It should be noted that water pipes and
storage vessels in unheated areas will generally need
to be insulated for the purpose of protection against
freezing. Guidance on suitable protection measures is
given in Report BR 262, Thermal insulation: avoiding
risks published by BRE.
2.2.4.2 Adequate insulation of hot water storage
vessels can be achieved by the use of a storage vessel
with factory-applied insulation of such characteristics
that, when tested on a 120 litre cylinder complying
with I.S. 161: 1975 using the method specified in
BS1566, Part 1: 2002, Appendix B, standing heat
losses are restricted to 0.8 W/litre. Use of a storage
33
APPENDICES
34
Appendix A:
Calculation of U-Values
GENERAL
A1.1 General Guidance on the Calculation of Uvalues is contained in Report BR 443 “Conventions
for the Calculation of U-values” 2006. For building
elements and components generally, the method of
calculating U-values is specified in I.S. EN ISO 6946:
1997. U-values of components involving heat transfer
to the ground, e.g. ground floors with or without
floor voids, basement walls, are calculated by the
method specified in I.S. EN ISO 13370: 1999. A soil
thermal conductivity of 2.0 W/mK should be used,
unless otherwise verified. U-values for windows,
doors and shutters may be calculated using I.S. EN
ISO 10077-1: 2000 or I.S. EN ISO 10077-2: 2000.
Information on U-values and guidance on calculation
procedures contained in the 1999 edition of CIBSE
Guide A3: Thermal Properties of Building Structures
are based on these standards and may be used to
show compliance with this Part.
A method for assessing U-values of light steelframed
constructions is given in Digest 465 “U-values for light
steel construction”, published by BRE. Guidance in
relation to the calculation of U-values for various
forms of metal clad construction can be found in
Technical Paper No. 14 “Guidance for the design of
metal roofing and cladding to comply with Approved
Document L2: 2001” published by MCRMA, Technical
Information Sheet No. 312, “Metal cladding: U-value
calculation assessing thermal performance of built-up
metal roof and wall cladding systems using rail and
bracket spacers” published by SCI and IP 10/02 “Metal
cladding: assessing thermal performance of built-up
systems which use ‘Z’ spacers” published by BRE.
A1.2 U-values derived by calculation should be
rounded to two significant figures and relevant
information on input data should be provided. When
calculating U-values the effects of timber joists,
structural and other framing, mortar bedding,
window frames and other small areas where thermal
bridging occurs must be taken into account. Similarly,
account must be taken of the effect of small areas
where the insulation level is reduced significantly
relative to the general level for the component or
structure element under consideration. Thermal
bridging may be disregarded, however, where the
general thermal resistance does not exceed that in
the bridged area by more than 0.1 m 2 K/W. For
example, normal mortar joints need not be taken
into account in calculations for brickwork or
concrete blockwork where the density of the brick
or block material is in excess of 1500 kg/m 3. A
ventilation opening in a wall or roof (other than a
window, rooflight or door opening), may be
considered as having the same U-value as the
element in which it occurs.
A1.3 Examples of the application of the calculation
method specified in I.S. EN 6946: 1977 are given
below. An example of the calculation of ground floor
U-values using I.S. EN ISO 13370: 1999 is also given.
A1.4 Thermal conductivities of common building
materials are given in Table A1 and for common
insulating materials in Table A2. For the most part,
these are taken from I.S. EN 12524: 2000 or CIBSE
Guide A3. See Paragraph 0.3.3 regarding application
of these Tables.
SIMPLE STRUCTURE
THERMAL BRIDGING
WITHOUT
A2.1 To calculate the U-value of a building
element (wall or roof) using I.S. EN ISO 6946: 1997,
the thermal resistance of each component is
calculated, and these thermal resistances, together
with surface resistances as appropriate, are then
combined to yield the total thermal resistance and
U-value. The result is corrected to account for
mechanical fixings (e.g. wall ties) or air gaps if
required. For an element consisting of homogenous
layers with no thermal bridging, the total resistance is
simply the sum of individual thermal resistances and
surface resistances.
I.S. EN 6946: 1997 provides for corrections to the
calculated U-value. In the case of example A1 (see
Diagram A1), corrections for air gaps in the insulated
layer and for mechanical fasteners may apply.
However, if the total correction is less than 3% of the
calculated value, the correction may be ignored.
In this case no correction for air gaps applies as it is
assumed that the insulation boards meet the
dimensional standards set out in I.S. EN ISO 6946:
1997 and that they are installed without gaps greater
than 5 mm. The construction involves the use of wall
ties that penetrate fully through the insulation layer.
35
Table A1
Thermal conductivity of some common building materials
Density
(kg/m3)
Material
General Building Materials
Clay Brickwork (outer leaf)
Clay Brickwork (inner leaf)
Concrete block (heavyweight)
Concrete block (medium weight)
Concrete block (autoclaved aerated)
Concrete block (autoclaved aerated)
Cast concrete, high density
Cast concrete, medium density
Aerated concrete slab
Concrete screed
Reinforced concrete (1% steel)
Reinforced concrete (2% steel)
Wall ties, stainless steel
Wall ties, galvanised steel
Mortar (protected)
Mortar (exposed)
External rendering (cement sand)
Plaster (gypsum lightweight)
Plaster (gypsum)
Plasterboard
Natural Slate
Concrete tiles
Clay tiles
Fibre cement slates
Ceramic tiles
Plastic tiles
Asphalt
Felt bitumen layers
Timber, softwood
Timber, hardwood
Wood wool slab
Wood-based panels (plywood, chipboard, etc.)
Thermal
Conductivity
(W/mK)
1,700
1,700
2,000
1,400
600
350
2,400
1,800
500
1,200
2,300
2,400
7,900
7,800
1,750
1,750
1,300
600
1,200
900
0.77
0.56
1.33
0.57
0.18
0.08
2.00
1.15
0.16
0.41
2.30
2.50
17.00
50.00
0.88
0.94
0.57
0.18
0.43
0.25
500
700
500
500
0.13
0.18
0.10
0.13
2,500
2,100
2,000
1,800
2,300
1,000
2,100
1,100
2.20
1.50
1.00
0.45
1.30
0.20
0.70
0.23
NOTE: The values in this table are indicative only. Certified values, should be used in preference, if available.
Table A2
Thermal conductivity of some common insulation materials
Material
Insulation
Expanded polystyrene (EPS) slab (HD)
Expanded polystyrene (EPS) slab (SD)
Extruded polystyrene
Mineral fibre / wool quilt
Mineral fibre / wool batt
Phenolic foam
Polyurethane board (unfaced)
Density
(kg/m3)
25
15
30
12
25
30
30
Thermal
Conductivity
(W/mK)
0.035
0.038
0.029
0.044
0.037
0.025
0.021
NOTE: The values in this table are indicative only. These may be used for early design purposes. Certified values, taking ageing into
account, where appropriate, should be used in final calculations (see para. 0.3.2.)
36
Example A1: Masonry cavity wall
Diagram A1
Masonry Cavity wall
(a)
The upper thermal resistance is based on the
assumption that heat flows through the
component in straight lines perpendicular to
the element's surfaces. To calculate it, all
possible heat flow paths are identified, for each
path the resistance of all layers are combined
in series to give the total resistance for the
path, and the resistances of all paths are then
combined in parallel to give the upper
resistance of the element.
(b)
The lower thermal resistance is based on the
assumption that all planes parallel to the
surfaces of the component are isothermal
surfaces. To calculate it, the resistances of all
components of each thermally bridged layer
are combined in parallel to give the effective
resistance for the layer, and the resistances of
all layers are then combined in series to give
the lower resistance of the element.
(c)
The total thermal resistance is the mean of the
upper and lower resistances.
Para. A.2.1
19 mm external render
100 mm dense concrete block
outer leaf
Cavity (min 40 mm residual cavity)
80 mm thermal insulation (thermal
conductivity 0.025 W/mK)
90 mm dense concrete block inner
leaf
13 mm lightweight plaster
HEAT FLOW
Layer/Surface
External surface
External render
Concrete Block
Air cavity
Insulation
Concrete Block
Plaster (lightweight)
Internal surface
Total Resistance
Thickness
(m)
Conductivity
(W/mK)
Resistance
(m2K/W)
----0.019
0.100
----0.080
0.100
0.013
-----
----0.57
1.33
----0.025
1.33
0.18
-----
0.040
0.033
0.075
0.180
3.200
0.075
0.072
0.130
-----
-----
3.805
U-value of construction = 1/3.805 = 0.26 W/m2K
A potential correction factor applies which, assuming
the use of 4 mm diameter stainless steel ties at 5 ties
per m2, is calculated as 0.006 W/m2K. This is less
than 3% of the calculated U-value and may be
ignored. It should be noted that, if galvanised steel
wall ties were used, a correction of 0.02 W/m2K
would apply, and the corrected U-value for this
construction would be 0.28 W/m2K.
Example A2: Timber-frame wall (with one
insulating layer bridged)
Diagram A2
Timber-frame wall
Para. A.2.2
102 mm brick outer leaf
Cavity (minimum 50mm)
Sheathing ply
150 mm insulating material
between studs (thermal
conductivity 0.04 W/mK)
Vapour control layer
13 mm plasterboard
HEAT FLOW
STRUCTURE WITH BRIDGED LAYER(S)
A2.2 For an element in which one or more layers
are thermally bridged, the total thermal resistance is
calculated in three steps as follows.
37
The thermal resistance of each component is
calculated (or, in the case of surface resistances,
entered) as follows:
Layer/Surface
External surface
Brick outer leaf
Air cavity
Sheathing ply
Mineral wool insulation
Timber studs
Plasterboard
Internal surface
Thickness
(m)
Conductivity
(W/mK)
Resistance
(m2 K / W)
--0.102
--0.012
0.150
0.150
0.013
---
--0.77
--0.13
0.04
0.13
0.25
---
0.040
0.132
0.180
0.092
3.750
1.154
0.052
0.130
Upper resistance
Assuming that heat flows in straight lines
perpendicular to the wall surfaces, there are two
heat flow paths - through the insulation and through
the studs. The resistance of each of these paths is
calculated as follows.
Resistance through section containing insulation [m2
K / W]:
External surface resistance
Brick outer leaf
Air cavity
Sheathing ply
Mineral wool insulation
Plasterboard
Internal surface resistance
0.040
0.132
0.180
0.092
3.750
0.052
0.130
Total
4.376
Resistance through section containing timber stud
[m2 K / W]
External surface resistance
Brick outer leaf
Air cavity
Sheathing ply
Timber studs
Plasterboard
Internal surface resistance
0.040
0.132
0.180
0.092
1.154
0.052
0.130
Total
1.780
38
The upper thermal resistance Ru is obtained from:
Ru = 1 / (F1 / R1 + F2 / R2)
where F1 and F2 are the fractional areas of heat flow
paths 1 and 2, and R1 and R2 are the resistances of
these paths.
Upper resistance Ru = 1 / (0.85 / 4.377 + 0.15 /
1.781) = 3.592 m2 K / W
Lower resistance
Assuming an isothermal plane on each face of the
layer of insulation which is bridged by timber studs,
the thermal resistance of this bridged layer, Rb, is
calculated from
Rb = 1 / (Fins / Rins + Ft / Rt)
where Fins and Ft are the fractional areas of insulation
and timber, and Rins and Rt are their resistances.
Rb = 1 / (0.85 / 3.750 + 0.15 / 1.154) = 2.804
m2 K / W
The resistances of all layers are then combined in
series to give the lower resistance [m2 K / W]
External surface resistance
Brick outer leaf
Air cavity
Bracing board
Bridged insulation layer
Plasterboard
Internal surface resistance
0.040
0.132
0.180
0.092
2.804
0.052
0.130
Lower resistance (Rl)
3.430
Total resistance
The total resistance Rt is given by:
Rt = (Ru + R1) / 2 = (3.59 + 3.431) / 2 = 3.511
m2 K / W
The U-value is the reciprocal of the total resistance:
U-value = 1 / 3.511 = 0.28 W/m2K (to 2 decimal
places).
There is a potential correction for air gaps in the
insulation layer. I.S. EN ISO 6946: 1997 gives a Uvalue correction of 0.0065 W/m 2 K for this
construction. This is less than 3% of the calculated
U-value and can be ignored.
Example A3: Domestic pitched roof with
insulation at ceiling level (between and
over joists).
Upper resistance (Ru)
Resistance through section containing both layers of
insulation [m2K/W]
A pitched roof has 100 mm of mineral wool tightly
fitted between 44 mm by 100 mm timber joists
spaced 600 mm apart (centres to centres) and 150
mm of mineral wool over the joists. The roof is
slated or tiled with sarking felt under the slates or
tiles. The ceiling consists of 13 mm of plasterboard.
The fractional area of timber at ceiling level is taken
as 8%.
External surface resistance
Resistance of roof space
Resistance of mineral wool over joists
Resistance of mineral wool
between joists
Resistance of plasterboard
Inside surface resistance
2.500
0.052
0.100
Total
6.642
Diagram A3
Domestic pitched roof
Resistance through section containing timber joists
Para. A.2.2
tiles or slates
35 mm timber battens
2 mm sarking felt
Rafters
Ventilated roof space
250 mm thermal insulation
(thermal conductivity 0.04
W/mK) with 100 mm laid
between timber ceiling joists
and 150 mm over joists with
vapour control layer, where
appropriate.
13 mm plasterboard ceiling
HEAT FLOW
Layer/Surface
Thickness Conductivity Resistance
(m)
(W/mK) (m2K/W)
External surface
Roof space (including sloping
construction and roof cavity)
Mineral wool (continuous layer)
Mineral wool (between joists)
Timber joists
Plasterboard
Internal surface
0.040
0.200
3.750
-
-
0.040
0.150
0.100
0.100
0.013
-
0.04
0.04
0.13
0.25
-
0.200
3.750
2.500
1.154
0.052
0.100
External surface resistance
Resistance of roof space
Resistance of mineral wool over joists
Resistance of timber joists
Resistance of plasterboard
Inside surface resistance
0.040
0.200
3.750
0.769
0.052
0.100
Total
4.911
The upper thermal resistance [Ru ] is obtained from:
Ru = 1 / (F1 / R1 + F2 / R2)
where F1 and F2 are the fractional areas of heat flow
paths 1 and 2, and R1 and R2 are the resistances of
these paths.
Upper resistance Ru = 1 / (0.92 / 6.642 + 0.08 /
4.911) = 6.460 m2 K/W
Lower resistance (Rl)
Assuming an isothermal plane on each face of the
layer of insulation which is bridged by timber studs,
the thermal resistance of this bridged layer, Rb, is
calculated from
Rb = 1 / (Fins / Rins + Ft / Rt)
where Fins and Ft are the fractional areas of insulation
and timber, and Rins and Rt are their resistances.
Rb = 1 / (0.92 / 2.500 + 0.08 / 0.769) = 2.119 m2K/W
39
The resistances of all layers are then combined in
series to give the lower resistance [m2K/W]
External surface resistance
Resistance of roof space
Resistance of mineral wool over joists
Resistance of bridged layer
Resistance of plasterboard
Inside surface resistance
0.040
0.200
3.750
2.119
0.052
0.100
Example A4: Slab-on-ground floor – full
floor insulation.
Lower resistance (Rl)
6.261
The slab-on-ground floor consists of a 150 mm
dense concrete ground floor slab on 100 mm
insulation. The insulation has a thermal conductivity
of 0.035 W/mK. The floor dimensions are 8750 mm
by 7250 mm with three sides exposed. One 8750
mm side abuts the floor of an adjoining semidetached house.
Total resistance
The total resistance Rt is given by:
Rt = (Ru + Rl) / 2 = (6.460 + 6.261) / 2 = 6.361
m2K/W
Diagram A4
Para. A.3.1
Concrete slab-on-ground floor
Edge insulation (min themal
resistance of 0.7m2K/W)
The U-value is the reciprocal of the total resistance:
U-value = 1 / 6.361 = 0.16 W/m2K (to 2 decimal
places).
150 mm dense concrete
I.S. EN ISO 6946: 1997 does not specify any potential
correction for this construction.
GROUND FLOORS AND BASEMENTS
A3.1 The U-value of an uninsulated ground floor
depends on a number of factors including floor shape
and area and the nature of the soil beneath the floor.
I.S. EN ISO 13370: 1999 deals with the calculation of
U-values of ground floors. Methods are specified for
floors directly on the ground and for floors with
vented and unvented sub-floor spaces. I.S. EN ISO
13370: 1999 also covers heat loss from basement
floors and walls.
A3.2 In the case of semi-detached or terraced
premises, blocks of flats and similar buildings, the
floor dimensions can be taken as either those of the
individual premises or those of the whole building.
Unheated spaces outside the insulated fabric, such as
attached porches or garages, should be excluded
when deriving floor dimensions but the length of the
floor perimeter between the heated building and the
unheated space should be included when
determining the length of exposed perimeter.
Where such ancillary areas have the potential to
become part of the habitable area of the dwelling,
floors should be insulated to the same level as the
dwelling floors unless it is envisaged that a new
insulated floor will be provided when converted.
40
Damp proof membrane. Where radon
barrier required, ensure correct
detailing to prevent passage of radon
gas into dwelling - see TGD C.
100mm thermal insulation
(thermal conductivity 0.035
W/mK)
In accordance with I.S. EN ISO 13370: 1999, the
following expression gives the U-value for wellinsulated floors:
U
=
λ
λ/(0.457B’ + dt), where
=
thermal conductivity of
unfrozen ground (W/mK)
=
2A/P (m)
=
w + λ(Rsi + Rf + Rse) (m)
=
floor area (m2)
=
heat loss perimeter (m)
=
wall thickness (m)
B’
dt
A
P
w
Rsi, Rf and Rse are internal surface resistance, floor
construction (including insulation) resistance and
external surface resistance respectively. Standard
values of R si and R se for floors are given as 0.17
m2K/W and 0.04 m2K/W respectively. The standard
also states that the thermal resistance of dense
concrete slabs and thin floor coverings may be
ignored in the calculation and that the thermal
conductivity of the ground should be taken as 2.0
W/mK unless otherwise known or specified.
Ignoring the thermal resistance of the dense
concrete slab, the thermal resistance of the floor
construction (Rf) is equal to the thermal resistance
of the insulation alone, i.e. 0.1/0.035 or 2.857 m2K/W.
Taking the wall thickness as 300 mm, this gives
dt
=
0.30 + 2.0(0.17 + 2.857 +
0.04) = 6.434 m.
Also
B’
=
2(8.75 x 7.25) / (8.75 +
7.25 + 7.25) = 5.457 m
Therefore
U
=
2.0 / ((0.457 x 5.457) +
6.434) = 0.22 W/m2K.
The edge insulation to the slab is provided to
prevent thermal bridging at the edge of the slab. I.S.
EN ISO 13370: 1999 does not consider this edge
insulation as contributing to the overall floor
insulation and thus reducing the floor U-value.
However, edge insulation, which extends below the
external ground level, is considered to contribute to
a reduction in floor U-value and a method of taking
this into account is included in the standard.
Foundation walls of insulating lightweight concrete
may be taken as edge insulation for this purpose.
ELEMENTS ADJACENT TO UNHEATED
SPACES
A4.1 As indicated in Paragraph 0.3.5, the
procedure for the calculation of U-values of
elements adjacent to unheated spaces (previously
referred to as semi-exposed elements) is given in I.S.
EN ISO 6946: 1997 and I.S. EN ISO 13789: 2000.
The following formulae may be used to derive
elemental U-values (taking the unheated space into
account) for typical housing situations irrespective of
the precise dimensions of the unheated space.
Uo = 1 /(1/U-Ru)
or U = 1 /(1/Uo+Ru)
Where: U – U-value of element adjacent to
unheated space (W/m2K), taking the
effect of the unheated space into
account.
Uo –
U-value of the element between
heated and unheated spaces
(W/m2K) calculated as if there was
no unheated space adjacent to the
element.
Ru – effective thermal resistance of
unheated space inclusive of all
external elements (m2 K / W).
This procedure can be used when the precise details
on the structure providing an unheated space are not
available, or not crucial.
Ru for typical unheated structures (including garages,
access corridors to flats and unheated
conservatories) are given in Tables A3, A4 and A5.
Table A5 applies only where a conservatory - style
sunroom is not treated as an integral part of the
dwelling i.e. is treated as an extension.
In the case of room-in-roof construction, the U-value
of the walls of the room-in-roof construction and of
the ceiling of the room below the space adjacent to
these walls can be calculated using this procedure.
See Diagram A5.
41
Table A3 Typical resistance (Ru) for unheated
space.
(a)
Integral and adjacent
single garages or other
similar unheated space.
(c) Conservatory-type
sunroom
Garage or other
similar unheated space
Element between garage
and dwelling
Ru
Single fully integral
Side wall, end wall
and floor
0.33
Single fully integral
One wall and floor
0.25
Single, partially integral
displaced forward
Side wall, end wall
and floor
0.26
Single, adjacent
One wall
0.09
The table gives Ru for single garages; use (0.5 x Ru) for double garages
when extra garage is not fully integral, and (0.85 x Ru) for fully integral
double garages. Single garage means a garage for one car; double garage
means a garage for two cars.
Table A4 Typical resistance (Ru) for unheated
space
(b) Unheated stairwells and
access corridors in flats
Flat
Exposed facing wall
Walls adjacent
to unheated
space
Unheated Stairwell or
Corridor
Flat
Unexposed facing wall
Corridor above or below
Unheated space
Stairwells:
Facing wall exposed
Facing wall not exposed
Access corridors:
Facing wall exposed, corridor
above or below
Facing wall exposed, corridors
above and below
Facing wall not exposed,
corridor above or below
42
Table A5 Typical resistance (Ru) for unheated
space
Ru
0.82
0.90
0.31
0.23
0.43
Number of walls between dwelling
and conservatory/sunroom
One
Two (conservatory in angle of dwelling)
Three (conservatory in recess)
Diagram A5
Room in roof
U-value calculated
as per normal roof
Treat as unheated
space
Ru = 0.5 m2K/W
Ru
0.06
0.14
0.25
Para. A.4.1
Room in roof
Treat as in
unheated space
Ru = 0.5 m2K/W
Elements adjacent
to an unheated
space
Appendix B:
Fabric Insulation: Additional Guidance for
Common Construction (- including Tables of Uvalues)
GENERAL
B.1
This Appendix provides some basic guidance
in relation to typical roof, wall and floor
constructions. Guidance is not exhaustive and
designers and contractors should also have regard to
other sources of relevant guidance e.g. BR.262,
Thermal Insulation; avoiding risks, relevant standards
and good building practice.
In particular, diagrams in this Appendix are intended
to be illustrative of the construction to which they
refer. They do not purport to provide detailed
guidance on the avoidance of thermal bridging. See
sections 1.3.3 and 2.1.3 for guidance on reasonable
provision in this regard.
B.2
For many typical roof, wall and floor
constructions, the thickness of insulation required to
achieve a particular U-value can be calculated
approximately by the use of the appropriate table
from this Appendix. The tables can also be used to
estimate the U-value achieved by a particular
thickness of insulating material. Higher performing
insulating materials, i.e. those with lower thermal
conductivities, can achieve any given U-value with a
lower thickness of insulating material.
B.3
These tables have been derived using the
methods described in Appendix A, taking into
account the effects of repeated thermal bridging
where appropriate. Figures derived from the tables
should be corrected to allow for any discrete nonrepeating thermal bridging which may exist in the
construction. A range of factors are relevant to the
determination of U-values and the values given in
these tables relate to typical constructions of the
type to which the tables refer. The methods
described in Appendix A can be used to calculate a
more accurate U-value for a particular construction
or the amount of insulation required to achieve a
particular U-value.
Example B1:
Partially filled cavity
What is the U-value of the construction shown in
Diagram B1.
Diagram B1
Partially filled cavity
Para. B.2
102 mm brick outer leaf
Cavity (min. 40 mm residual
cavity)
100 mm thermal insulation
(thermal conductivity 0.032
W/mK)
100 mm dense concrete block
inner leaf
13 mm lightweight plaster
HEAT FLOW
Table B9 gives U-values of 0.29 W/m2K and 0.25
W/m 2 K for 100 mm insulation of thermal
conductivity of 0.035 W/mK and 0.030 W/mK
respectively. By linear interpolation, the U-value of
this construction, with 100 mm of insulation of
thermal conductivity of 0.032 W/mK, is 0.27 W/m2K.
B.4
Intermediate U-values and values of required
thickness of insulation can be obtained from the
tables by linear interpolation.
43
Example B2:
Timber frame wall
Diagram B2
Timber frame wall
Para. B.2
102 mm brick outer
leaf
Cavity
Sheathing ply
150 mm insulating
material between
studs
(thermal conductivity
0.04 W/mK)
Vapour control layer
13 mm plasterboard
What is the U-value of this construction?
Table B1 gives the U-value for 250 mm of insulation
of thermal conductivity of 0.04 W/mK as
0.16 W/m2 K.
ROOF CONSTRUCTIONS
B.5.1 Construction R1: Tiled or slated
pitched roof, ventilated roof space ,
insulation at ceiling level.
B.5.1.1 R1(a) Insulation between and over
joists
Diagram B4
Para. B.5.1.1
Insulation between and over joists
HEAT FLOW
What is the U-value of this construction?
Table B14 gives the U-value for 150 mm of insulation
of thermal conductivity of 0.035 W/mK as 0.27
W/m2K.
Tiled or slated roof
35 mm timber battens
2 mm sarking felt
Rafters
Ventilated roof space
Example B3: Pitched roof
Diagram B3
Pitched roof
Para. B.2
Tiles or slates
35 mm timber battens
2 mm sarking felt
Rafters
Ventilated roof space
250 mm thermal
insulation (thermal
conductivity 0.04
W/mK) with 100 mm
laid between timber
ceiling joists and 150
mm over joists with
vapour control layer,
where appropriate
13 mm plasterboard
ceiling
HEAT FLOW
44
Insulation between and over
joists
Vapour control layer
(where appropriate)
13mm plasterboard
Table B1 U-values for tiled or slated pitched
roof, ventilated roof space, insulation
placed between and over joists at
ceiling level
Total
Thickness of
insulation
(mm)
150
175
200
225
250
275
300
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.27
0.23
0.20
0.18
0.16
0.14
0.13
0.24
0.20
0.18
0.16
0.14
0.13
0.12
0.21
0.18
0.16
0.14
0.12
0.11
0.10
U-Value of construction
0.025
0.020
0.18
0.15
0.13
0.12
0.11
0.10
0.09
0.16
0.13
0.11
0.10
0.09
0.08
0.07
(W/m2K)
This table is derived for roofs with:
Tiles or slates, felt, ventilated roof space, timber joists (λ =
0.13) with the spaces between fully filled with insulation and
the balance of insulation above and covering joists. (see
Diagram B4). Calculations assume a fractional area of timber
thermal bridging of 9%. (includes allowance for loft hatch
framing)
Installation guidelines and precautions
Care is required in design and construction,
particularly in regard to the following:
Provision of adequate roofspace ventilation
Adequate ventilation is particularly important to
ensure the prevention of excessive condensation in
cold attic areas. See relevant guidance in TGD F.
Minimising transfer of water vapour from
occupied dwelling area to cold attic space
In addition to ensuring adequate ventilation,
measures should be taken to limit transfer of water
vapour to the cold attic. Care should be taken to seal
around all penetrations of pipes, ducts, wiring, etc.
through the ceiling, including provision of an effective
seal to the attic access hatch. Use of a vapour control
layer at ceiling level, on the warm side of the
insulation, will assist in limiting vapour transfer, but
cannot be relied on as an alternative to ventilation. In
particular, a vapour control layer should be used
where the roof pitch is less than 150, or where the
shape of the roof is such that there is difficulty in
ensuring adequate ventilation, e.g. room-in-the-roof
construction.
Minimising the extent of cold bridging.
Particular areas of potential cold bridging include
junctions with external walls at eaves and gables, and
junctions with solid party walls. Gaps in the insulation
should be avoided and the insulation should fit tightly
against joists, noggings, bracing etc. Insulation joints
should be closely butted and joints in upper and
lower layers of insulation should be staggered.
Protecting water tanks and pipework against the
risk of freezing.
All pipework on the cold side of the insulation
should be adequately insulated. Where the cold
water cistern is located in the attic, as is normally the
case, the top and sides of the cistern should be
insulated. The area underneath the cistern should be
left uninsulated and continuity of tank and ceiling
insulation should be ensured e.g. by overlapping the
tank and ceiling insulation. Provision should be made
to ensure ventilation of the tank.
Ensuring that there is no danger from
overheating of electric cables or fittings.
Cables should be installed above the insulation.
Cables which pass through or are enclosed in
insulation should be adequately rated to ensure that
they do not overheat. Recessed fittings should have
adequate ventilation or other means to prevent
overheating.
Providing for access to tanks, services and fittings
in the roofspace.
Because the depth of insulation will obscure the
location of ceiling joists, provision should be made
for access from the access hatch to the cold water
tank and to other fittings to which access for
occasional maintenance and ser vicing may be
required. This can be done by provision of walkways
without compressing the installed insulation.
45
B.5.1.2 R1(b) Insulation between and
below joists.
Insulation is laid in one layer between the joists,
protruding above them where its depth is greater,
and leaving air gaps above the joists. A composite
board of plasterboard with insulation backing is used
for the ceiling.
150 mm insulation
between ceiling
joists
Additional insulation
below joists
Vapour control
layer
13 mm plasterboard
ceiling
Table B2 U-values for tiled or slated pitched
roof, ventilated roof space, insulation
placed between and below joists at
ceiling level
10
20
30
40
50
60
70
80
90
100
110
120
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.27
0.26
0.24
0.22
0.21
0.20
0.19
0.18
0.17
0.17
0.16
0.15
0.27
0.25
0.23
0.22
0.20
0.19
0.18
0.17
0.16
0.16
0.15
0.14
0.27
0.24
0.22
0.21
0.19
0.18
0.17
0.16
0.15
0.15
0.14
0.13
0.26
0.24
0.21
0.20
0.18
0.17
0.16
0.15
0.14
0.13
0.13
0.12
0.26
0.22
0.20
0.18
0.17
0.15
0.14
0.13
0.12
0.12
0.11
0.10
U-Value of construction (W/m2K)
This table is derived for roofs as in Table B1 but with 150
mm of insulation (λ = 0.04) between ceiling joists, and the
remainder below the joists. Insulation of thickness and
thermal conductivity as shown in the table is below joists.
(See Diagram B5).
(The insulation thickness shown does not include the
thickness of plasterboard in composite boards).
46
B.5.2 Construction R2: Tiled or slated
pitched roof, occupied or unventilated
roof space, insulation on roof slope.
B.5.2.1 R2(a) Insulation between and
below rafters, 50 mm ventilated cavity
between insulation and sarking felt.
Diagram B5
Para. B.5.1.2
Insulation between and below joists
Total
Thickness of
insulation
(mm)
Installation guidelines and precautions.
Similar guidelines and precautions apply as for R1(a)
above.
Diagram B6
Para. B.5.2.1
Insulation between and below rafters
Tiles or slates on
battens, sarking felt and
rafters
50 mm ventilated air
space
Insulation between and
below rafters
Vapour control layer
13 mm plasterboard
ceiling
Occupied / unventilated roof space
Table B3 U-values for tiled or slated pitched
roof, occupied or unventilated roof
space, insulation placed between and
below rafters
Total
Thickness of
insulation
(mm)
120
140
160
180
200
220
240
260
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.34
0.29
0.25
0.22
0.20
0.18
0.17
0.15
0.31
0.26
0.23
0.20
0.18
0.16
0.15
0.14
0.27
0.23
0.20
0.17
0.16
0.14
0.13
0.12
U-Value of construction
This table is derived for roofs with:
0.025
0.020
0.24
0.20
0.17
0.15
0.13
0.12
0.11
0.10
0.20
0.16
0.14
0.12
0.11
0.10
0.09
0.08
(W/m2K)
Table B3 assumes that the thermal conductivity of
insulation between and below the rafters is the same.
If different insulation materials are used, the material
on the warm side (i.e. below rafters) should have a
vapour resistance no lower than that on the cold
side (i.e. between rafters).
B.5.2.2 R2(b): Insulation above and
between rafters, slate or tile underlay of
breather membrane type.
Diagram B7
Para. 5.2.2
Insulation above and between rafters
Tiles or slates on battens
Vapour permeable
membrane (underlay)
Counter battens
Insulation over and
between rafters
Vapour control layer
13 mm plasterboard
Tiles or slates, felt, rafters of depth 150 mm (λ = 0.13), 50 mm
ventilated air space above insulation, 100 mm insulation
between rafters, balance of insulation below and across rafters.
(See Diagram B6).
A fractional area of timber of 8% is assumed. Battens may be
fixed to the underside of the rafters to increase rafter depth if
necessary.
Installation guidelines and precautions.
The insulation is installed in two layers, one between
the rafters (and battens) and the second below and
across them. To limit water vapour transfer and
minimise condensation risks, a vapour control layer is
required on the warm side of the insulation. No
material of high vapour resistance, e.g. facing layer
attached to insulation to facilitate fixing, should be
included within the overall thickness of insulation.
Care must be taken to prevent roof timbers and
access problems interfering with the continuity of
insulation and vapour control layer.
Provision should be made for ventilation top and
bottom of the 50 mm ventilation gap on the cold
side of the insulation.
An alternative construction using a breathable
membrane may be used. In this case the membrane
should be certified in accordance with Part D of the
Building Regulations and installed in accordance with
the guidance on the certificate.
Care should be taken to avoid thermal bridging at
roof-wall junctions at eaves, gable walls and party
walls.
Table B4 U-values for tiled or slated pitched
roof, occupied or unventilated roof
space, insulation placed between and
above rafters.
Total
Thickness of
insulation
(mm)
120
140
160
180
200
220
240
260
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
U-Value of construction (W/m2K)
0.33
0.28
0.25
0.22
0.20
0.18
0.16
0.15
0.33
0.25
0.22
0.20
0.18
0.16
0.15
0.13
0.27
0.22
0.19
0.17
0.15
0.14
0.13
0.12
0.23
0.19
0.17
0.15
0.13
0.12
0.11
0.10
0.020
0.20
0.16
0.14
0.12
0.11
0.10
0.09
0.08
This table is derived for roofs with:
Tiles or slates, tiling battens, vapour permeable membrane (as
underlay), counter battens, insulation layer over rafters, rafters
with insulation fitted between. (See Diagram B7).
Insulation between and over rafters has the same thermal
conductivity. A fractional area of timber of 8% is assumed.
47
Installation guidelines and precautions
The effective performance of this system is critically
dependent on the prevention of air and water
vapour movement between the warm and cold sides
of the insulation. Only systems which are certified or
shown by test and calculation as appropriate for this
function, (see TGD D, Paragraph 1.1 (a) and (b))
should be used. The precise details of construction
are dependent on the insulation and roof underlay
materials to be used. Installation should be carried
out precisely in accordance with the procedures
described in the relevant certificate.
In general, the insulation material must be of low
vapour permeability, there should be a tight fit
between adjacent insulation boards, and between
insulation boards and rafters. All gaps in the
insulation (e.g. at eaves, ridge, gable ends, around
rooflights and chimneys, etc.) should be sealed with
flexible sealant or expanding foam.
Care should be taken to avoid thermal bridging at
roof-wall junctions at eaves, gable walls and party
walls.
B.5.3 Construction R3: Flat roof, timber
joists, insulation below deck
B.5.3.1 R3(a) Insulation between joists, 50
mm air gap between insulation and roof
decking
The insulation is laid between the joists. The depth of
the joists is increased by means of battens if
required.
Diagram B8
Timber flat roof, insulation
between joists
Para. B.5.3.1
Waterproof
decking
50 mm
ventilated air
space
Insulation
between joists
Vapour
control layer
13 mm
plasterboard
48
Table B5 U-values for timber flat roof,
insulation between joists, 50 mm
ventilated air gap between insulation
and roof decking.
Total
Thickness of
insulation
(mm)
150
175
200
225
250
275
300
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.29
0.25
0.22
0.20
0.18
0.16
0.15
0.26
0.23
0.20
0.18
0.16
0.15
0.14
0.24
0.20
0.18
0.16
0.15
0.13
0.12
U-Value of construction
0.025
0.020
0.21
0.18
0.16
0.14
0.13
0.12
0.11
0.18
0.16
0.14
0.12
0.11
0.10
0.09
(W/m2K)
This table is derived for roofs with:
Weatherproof deck, ventilated air space, insulation as given
above between timber joists (λ = 0.13), 13 mm plasterboard
(λ = 0.25). (See Diagram B8).
The calculations assume a fractional area of timber of 8%.
Installation guidelines and precautions
A vapour control layer sealed at all joints, edges and
penetrations, is required on the warm side of the
insulation, and a ventilated air space as specified in
TGD F provided above the insulation. Cross
ventilation should be provided to each and every
void. When installing the insulation, care is needed to
ensure that it does not block the ventilation flow
paths.
The integrity of the vapour control layer should be
ensured by effective sealing of all ser vice
penetrations, e.g. electric wiring, or by provision of a
services zone immediately above the ceiling, but
below the vapour control layer.
The roof insulation should connect with the wall
insulation so as to avoid a cold bridge at this point.
B.5.3.2 R3(b) Insulation between and
below joists, 50 mm air gap between
insulation and roof decking
The insulation may be installed in two layers, one
between the joists as described above, and the
second below the joists. This lower layer may be in
the form of composite boards of plasterboard
backed with insulation, with integral vapour barrier,
fixed to the joists. The edges of boards should be
sealed with vapour-resistant tape.
B.5.4 Construction R4: Sandwich warm
deck flat roof
The insulation is installed above the roof deck but
below the weatherproof membrane. The structural
deck may be of timber, concrete or metal.
Diagram B9
Para. B.5.4
Sandwich warm deck flat
roof above a concrete structure
Waterproof
membrane
Insulation
Table B6 U-values for timber flat roof,
insulation between and below joists,
50 mm ventilated air gap between
insulation and roof decking.
Total
Thickness of
insulation
(mm)
20
40
60
80
100
120
140
160
High performance
vapour barrier
Concrete screed
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.34
0.29
0.25
0.22
0.20
0.18
0.17
0.15
0.33
0.28
0.24
0.21
0.19
0.17
0.15
0.14
0.32
0.27
0.22
0.20
0.17
0.15
0.14
0.13
0.31
0.25
0.21
0.18
0.15
0.14
0.12
0.11
0.29
0.22
0.18
0.15
0.13
0.12
0.11
0.10
U-Value of construction (W/m2K)
This table is derived for roofs as in Table B5 above, except
with 100 mm of insulation (λ = 0.04) between 150 mm joists,
and composite board below joists consisting of 10 mm
plasterboard (λ= 0.25) backed with insulation as specified in
this table.
Dense concrete
roofslab
Table B7 U-values for sandwich warm deck flat
roof.
Total
Thickness of
insulation
(mm)
100
125
150
175
200
225
250
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.34
0.28
0.24
0.21
0.18
0.16
0.15
0.30
0.25
0.21
0.18
0.16
0.14
0.13
0.26
0.22
0.18
0.16
0.14
0.13
0.11
U-Value of construction
0.025
0.020
0.22
0.18
0.15
0.13
0.12
0.11
0.10
0.18
0.15
0.13
0.11
0.10
0.09
0.08
(W/m2K)
This table is derived for roofs with:
12 mm felt bitumen layers (λ = 0.23), over insulation as given in
the table, over 50 mm screed (λ = 0.41), over 150 mm concrete
slab (λ = 2.30), over 13 mm plasterboard (λ = 0.25). (See
Diagram B9).
49
Installation guidelines and precautions
The insulation boards are laid over and normally fully
bonded to a high performance vapour barrier
complying with BS 747: 2000 which is bonded to the
roof deck. The insulation is overlaid with a
waterproof membrane, which may consist of a single
layer membrane, a fully-bonded built-up bitumen
roofing system, or mastic asphalt on an isolating layer.
At the perimeter, the vapour barrier is turned up and
back over the insulation and bonded to it and the
weatherproof membrane. Extreme care is required
to ensure that moisture can not penetrate the
vapour barrier.
Diagram B10
Inverted warm deck roof with
concrete structure
Paving slab or ballast
Filtration layer
Insulation (low water
absorptivity, frost
resistance)
Asphalt or
waterproof
membrane
Concrete screed
The insulation should not be allowed to get wet
during installation.
There should be no insulation below the deck. This
could give rise to a risk of condensation on the
underside of the vapour barrier.
Thermal bridging at a roof / wall junction should be
avoided.
B.5.5 Construction R5: Inverted warm
deck flat roof: insulation to falls above
both roof deck and weatherproof
membrane
Insulation materials should have low water
absorption, be frost resistant and should maintain
performance in damp conditions over the long term.
To balance loss of performance due to the damp
conditions and the intermittent cooling effect of
water passing through and draining off from the
warm side of the insulation, the insulation thickness
calculated as necessary for dry conditions should be
increased by 20%.
50
Para. B.5.5
Concrete roofslab
Table B8 U-values for sandwich warm deck flat
roof.
Total
Thickness of
insulation
(mm)
100
125
150
175
200
225
250
275
300
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.42
0.37
0.33
0.30
0.28
0.26
0.25
0.24
0.23
0.39
0.34
0.30
0.28
0.26
0.24
0.23
0.22
0.21
0.35
0.31
0.28
0.26
0.24
0.23
0.21
0.21
0.20
0.32
0.28
0.25
0.23
0.22
0.21
0.20
0.19
0.18
0.28
0.25
0.23
0.21
0.20
0.19
0.18
0.18
0.17
U-Value of construction (W/m2K)
This table is derived for roofs with: 50 mm gravel ballast (λ=
2.0) over 40 mm screed (λ= 0.50) over 40 mm screed (λ=
0.41) over 150 mm concrete (λ= 2.30) over 13 mm
plasterboard (λ = 0.25). Insulation thickness derived using
correction factor for rain water flow given in I.S. EN 6946.
(See Diagram B10).
Installation guidelines and precautions
The insulation is laid on the waterproof membrane.
A filtration layer is used to keep out grit, which could
eventually damage the weatherproof membrane. The
insulation must be restrained to prevent wind uplift
and protected against ultraviolet degradation. This is
usually achieved by use of gravel ballast, paving stones
or equivalent restraint and protection. The insulation
should have sufficient compressive strength to
withstand the weight of the ballast and any other
loads.
Rainwater will penetrate the insulation as far as the
waterproof membrane. Drainage should be provided
to remove this rainwater. To minimise the effect of
rain on performance, insulation boards should be
tightly jointed (rebated or tongued-and-grooved
edges are preferred), and trimmed to give a close fit
around upstands and service penetrations.
To avoid condensation problems, the thermal
resistance of the construction between the
weatherproof membrane and the heated space is at
least 0.15 m2K/W. However, this thermal resistance
should not exceed 25% of the thermal resistance of
the whole construction.
Thermal bridging at roof / wall junctions should be
avoided.
WALL CONSTRUCTIONS
B.6.1. W1: Cavity walls, insulation in
cavity, cavity retained (partial fill)
B.6.1.1 W1(a) Brick or rendered dense
concrete block external leaf, partial fill
insulation, dense concrete block inner leaf,
plaster or plasterboard internal finish.
Diagram B11
Para. B.6.1.1
Cavity wall with partial-fill insulation
External leaf
(brick or dense concrete block with
external render)
Air space (min. 40 mm)
Insulation
Inner leaf (concrete block, plaster or
plasterboard)
The following tables deal with walls with maximum
overall cavity width of 150 mm, which is the greatest
cavity width for which details of construction are
given in I.S. 325 Part 1: 1986, Code of Practice for the
structural use of concrete; Structural use of unreinforced
concrete. Where it is proposed to use wider cavity
widths, full structural and thermal design will be
necessary.
Table B9 U-values for brick (or rendered
dense concrete block) external leaf,
partial fill insulation, dense concrete
block inner leaf, plaster (or
plasterboard) internal finish.
Total
Thickness of
insulation
(mm)
60
80
100
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.48
0.39
0.32
0.43
0.35
0.29
0.39
0.31
0.25
U-Value of construction
0.025
0.020
0.33
0.26
0.22
0.28
0.22
0.18
(W/m2K)
This table is derived for walls with:
102 mm clay brickwork outer leaf (λ= 0.77), 50 mm air
space, insulation as specified in table, 100 mm concrete
block inner leaf (density = 1800 kg/m3, λ = 1.13), 13 mm
dense plaster (λ = 0.57). (See Diagram B11). The effects of
wall ties are assumed to be negligible.
51
The insulation thickness required to achieve a given
U-value may be reduced by using lightweight
concrete insulating blocks for the inner leaf, as
shown in the table below.
Table B10 U-values for construction as Table B9
except for lightweight concrete block
inner leaf.
Total
Thickness of
insulation
(mm)
60
80
100
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.40
0.34
0.29
0.37
0.31
0.26
0.34
0.27
0.23
U-Value of construction
0.025
0.020
0.30
0.24
0.20
0.25
0.20
0.17
(W/m2K)
This table is derived for walls as in Table B9, except
heavyweight concrete block inner leaf replaced with 100
mm insulating block (λ = 0.18).
Calculations assume a 7% fractional area of mortar (λ =
0.88) bridging the inner leaf.
Note that the sound attenuation performance of
lightweight blocks is not as good as that of heavier
blocks. This may limit their suitability for use in the
inner leafs of attached dwellings.
Installation guidelines and precautions
Insulation should be tight against the inner leaf. Any
excess mortar should be cleaned off before fixing
insulation. The insulation layer should be continuous
and without gaps. Insulation batts should butt tightly
against each other. Mortar droppings on batts should
be avoided. Batts should be cut and trimmed to fit
tightly around openings, cavity trays, lintels, sleeved
vents and other components bridging the cavity, and
should be adequately supported in position.
Critical locations where care should be taken to limit
thermal bridging include lintels, jambs, cills, roof-wall
junctions and wall-floor junctions. The method of
cavity closure used should not cause thermal bridge
at the roof-wall junction.
B.6.1.2 W1(b): As W1(a) except with
insulation partly in cavity and partly as
internal lining.
If composite boards of plasterboard backed with
insulation (of similar conductivity to that used in the
cavity) are used internally. Table B9 and B10 can be
taken as applying to the total insulation thickness
(cavity plus internal). If internal insulation is placed
between timber studs, total insulation thickness will
be slightly higher due to the bridging effect of the
studs. Table B11 applies in this case.
Table B11 U-values for brick (or rendered dense
concrete block) external leaf, 60mm
partial fill insulation (λ = 0.035), dense
concrete block inner leaf, plasterboard
fixed to timber studs , insulation
between studs.
Total
Thickness of
insulation
(mm)
40
60
80
100
120
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.31
0.28
0.25
0.23
0.21
0.31
0.27
0.24
0.22
0.20
0.29
0.26
0.23
0.20
0.18
U-Value of construction
0.025
0.020
0.28
0.24
0.21
0.19
0.17
0.26
0.22
0.19
0.17
0.15
(W/m2K)
This table is derived for walls as in Table B9 above, except with
60 mm of insulation of λ = 0.035 in cavity, and insulation as
specified in the table applied to the internal surface of the wall
between timber studs (λ = 0.13) of fractional area 12%, with a
wall finish of 13 mm plasterboard (λ = 0.25).
Lower U-values, or reduced insulation thickness, can
be achieved by using insulating concrete blockwork
(rather than dense concrete) between the cavity and
internal insulation.
Insulation partly in cavity and partly as internal lining
helps minimise thermal bridging. Internal insulation
limits thermal bridging at floor and roof junctions,
whereas cavity insulation minimises thermal bridging
at separating walls and internal fixtures.
Installation guidelines and precautions
Installation of insulation in the cavity should follow
the guidelines given above for construction W1(a)
(partial-fill cavity insulation), and installation of the
52
internal lining should follow the guidelines given
below for construction W4 (hollow-block).
B.6.2. Construction W2: Cavity walls,
insulation in cavity, no residual cavity (fullfill)
The insulation fully fills the cavity. Insulation may be in
the form of semi-rigid batts installed as wall
construction proceeds, or loose-fill material blown
into the cavity after the wall is constructed; the
former is considered here. Insulation material
suitable for cavity fill should not absorb water by
capillary action and should not transmit water from
outer to inner leaf. Such insulation may extend below
dpc level.
Diagram B12
Cavity wall with full-fill insulation
Para. B.6.2
External leaf
(rendered dense concrete
block)
Insulation
Inner leaf (concrete block,
plaster or plasterboard)
Table B12 U-values for rendered dense
concrete block external leaf, full-fill
insulation dense concrete block inner
leaf, plaster (or plasterboard)
internal finish.
Total
Thickness of
insulation
(mm)
60
80
100
120
140
160
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.51
0.41
0.34
0.29
0.25
0.22
0.46
0.37
0.30
0.26
0.22
0.20
0.41
0.32
0.26
0.22
0.20
0.17
0.35
0.27
0.22
0.19
0.17
0.15
0.29
0.22
0.18
0.16
0.13
0.12
U-Value of construction (W/m2K)
This table is derived for walls with:
20 mm external rendering (λ = 0.57), 102 mm clay brickwork
outer leaf (λ = 0.77), insulation as specified in table, 100 mm
concrete block inner leaf (medium density - 1800 kg/m3, λ =
1.13), 13 mm dense plaster (λ= 0.57). The effects of wall ties
are assumed to be negligible. (See Diagram B12).
The insulation thickness required to achieve a given
U-value may be reduced by using insulating concrete
blocks for the inner leaf, as shown in the table below.
Table B13 U-values for rendered dense
concrete block external leaf, full-fill
insulation, lightweight concrete block
inner leaf, plaster (or plasterboard)
internal finish.
Total
Thickness of
insulation
(mm)
60
80
100
120
140
160
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.43
0.35
0.30
0.26
0.23
0.21
0.39
0.32
0.27
0.23
0.21
0.18
0.35
0.29
0.24
0.21
0.18
0.16
U-Value of construction
0.025
0.020
0.31
0.25
0.21
0.18
0.16
0.14
0.26
0.21
0.17
0.15
0.13
0.11
(W/m2K)
This table is derived for walls as above, except heavyweight
concrete block inner leaf replaced with 100 mm insulating
block (λ = 0.18).
Calculations assume a 7% fractional area of mortar (λ= 0.88)
bridging the inner leaf.
53
Installation guidelines and precautions
Only certified insulation products should be used,
and the installation and other requirements specified
in such certificates should be fully complied with. In
particular, regard should be had to the exposure
conditions under which use is certified and any
limitations on external finish associated therewith.
Guidance on minimising air gaps and infiltration in
partial-fill cavity insulation applies also to full-fill
insulation.
Similar issues regarding avoidance of thermal bridging
as for construction apply.
B.6.3
Construction W3: Timber frame
wall, brick or rendered concrete block
external leaf
B.6.3.1 W3(a) Insulation between studs
The insulation is installed between studs, whose
depth equals or exceeds the thickness of insulation
specified.
In calculating U-values, the fractional area of timber
bridging the insulation should be checked. Account
should be taken of all timber elements which fully
bridge the insulation, including studs, top and bottom
rails, noggings, timbers around window and door
openings and at junctions with internal partitions,
party walls and internal floors. In the table a
fractional area of 15% is assumed.
Diagram B13
Para. B.6.3.1
Timber frame wall, insulation
between framing timbers
External leaf
(brick or rendered dense
concrete block)
50 mm air cavity
Breather membrane
Sheathing board
Insulation
Vapour control layer
Plasterboard
54
Table B14 U-values for brick (or rendered
dense concrete block) external leaf,
timber frame inner leaf, insulation
between timber studs, plasterboard
internal finish.
Total
Thickness of
insulation
(mm)
100
125
150
175
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.39
0.33
0.29
0.25
0.36
0.31
0.27
0.23
0.34
0.28
0.24
0.21
0.31
0.28
0.24
0.21
0.28
0.23
0.20
0.18
U-Value of construction (W/m2K)
This table is derived for walls with:
102 mm clay brickwork outer leaf (λ = 0.77), 50 mm air
cavity, breather membrane, 12 mm sheathing board (λ =
0.14), insulation between timber studs (λ= 0.13), vapour
control layer, 13 mm plasterboard (λ= 0.25). (See Diagram
B13).
The calculations assume a fractional area of timber thermal
bridging of 15%.
Installation guidelines and precautions
Air gaps in the insulation layer, and between it and
the vapour barrier, should be avoided. Insulation batts
should be friction fitted between studs to minimise
gaps between insulation and joists. Adjacent
insulation pieces should butt tightly together.
Particular care is needed to fill gaps between closelyspaced studs at wall/wall and wall/floor junctions, and
at corners of external walls.
A vapour control layer should be installed on the
warm side of the installation. There should be no
layers of high vapour resistance on the cold side of
the insulation.
Care is required to minimise thermal bridging of the
insulation by timber noggings and other inserts.
B.6.3.2 W3(b): Insulation between and
across studs
Where the chosen stud depth is not sufficient to
accommodate the required thickness of insulation,
insulation can be installed to the full depth between
the studs with additional insulation being provided as
an internal lining. This additional insulation may be
either in the form of plasterboard/insulation
composite board or insulation between timber
battens, to which the plasterboard is fixed.
Table B15 U-values for brick (or rendered
dense concrete block) external leaf,
timber frame inner leaf, insulation
between 100 mm timber studs,
additional insulation, plasterboard
internal finish.
Total
Thickness of
insulation
(mm)
20
40
60
80
100
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.32
0.28
0.24
0.22
0.19
0.32
0.27
0.23
0.20
0.18
0.31
0.25
0.22
0.19
0.17
0.29
0.24
0.20
0.17
0.15
0.28
0.22
0.18
0.15
0.13
U-Value of construction (W/m2K)
B.6.4 Construction W4: Hollow concrete
block wall, rendered externally, internal
insulation lining with plasterboard finish.
The insulation is installed on the inner face of the
Diagram B14
Hollow-block wall, internal
insulation lining
Rendered hollow concrete
block
Insulation
Vapour control layer
Plasterboard
This table is derived for walls as in W3(a) above, except
with 100 mm of insulation of λ = 0.04 between 100mm
studs, and an additional layer of insulation as specified in the
table across the studs.
The vapour control layer should be on the warm
side of the insulation. If different types of insulation
are used between and inside the studs, the vapour
resistance of the material between the studs should
not exceed that of the material across them.
Para. B.6.4
masonr y walls. It may be installed between
preservative-treated timber studs fixed to the wall,
or in the form of composite boards of plaster backed
with insulation, or as a combination of these.
Installation guidelines and precautions
Air Movement
Air gaps in the insulation layer should be kept to a
minimum. If using insulation between timber studs,
there should be no gaps between insulation and
studs, between insulation and the vapour control
layer, between butt joints in the insulation, around
service penetrations, etc. If using composite boards,
they should be tightly butted at edges, and should
provide complete and continuous coverage of the
external wall.
When mounting composite boards on plaster dabs
or timber battens, there is a danger that air will be
able to circulate behind the insulation, reducing its
effectiveness. To minimise such air movement, the air
gap behind the boards should be sealed along top
and bottom, at corners and around window and
door openings e.g. with continuous ribbon of plaster
or timber studs.
55
Table B16 U-values for hollow-block wall,
rendered externally, plasterboard
fixed to timber studs internally,
insulation between studs.
Total
Thickness of
insulation
(mm)
50
75
100
125
150
175
200
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
U-Value of construction (W/m2K)
0.67
0,50
0.40
0.34
0.29
0.25
0.22
0.63
0.47
0.37
0.31
0.26
0.23
0.21
0.58
0.43
0.34
0.28
0.24
0.21
0.19
0.53
0.39
0.31
0.25
0.22
0.19
0.17
0.020
Thermal Bridging
0.47
0.34
0.27
0.23
0.19
0.17
0.15
Table B17 U-values of hollow-block wall,
rendered externally, composite
insulation/ plasterboard internally,
fixed to timber battens [or plaster
dabs]
Total
Thickness of
insulation
(mm)
40
50
60
70
80
90
100
110
120
130
140
150
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.63
0.55
0.48
0.43
0.39
0.35
0.32
0.30
0.28
0.26
0.25
0.23
0.58
0.50
0.44
0.39
0.35
0.32
0.29
0.27
0.25
0.23
0.22
0.21
0.52
0.45
0.39
0.34
0.31
0.28
0.26
0.24
0.22
0.20
0.19
0.18
0.46
0.39
0.34
0.30
0.26
0.24
0.22
0.20
0.19
0.17
0.16
0.15
0.39
0.32
0.28
0.25
0.22
0.20
0.18
0.16
0.15
0.14
0.13
0.12
U-Value of construction (W/m2K)
These tables are derived for walls with:
19 mm external rendering (λ = 1.00), 215 mm hollow concrete
block (thermal resistance = 0.21 W/m2K), insulation fixed as
stated, vapour control layer, 13 mm plasterboard (λ = 0.25).
(See Diagram B14).
The calculations assume a fractional area of timber thermal
bridging of 12% or plaster dab thermal bridging of 20%. as
appropriate of 8%.
Condensation
A vapour control layer (e.g. 500 gauge polythene)
should be installed on the warm side of the
insulation to minimise the risk of interstitial
56
condensation on the cold masonry behind the
insulation. Care should be taken to avoid gaps in the
vapour control layer at all joints, edges and service
penetrations. The location of service runs in the air
gap on the cold side of the insulation should be
avoided.
Care should be taken to minimise the impact of
thermal bridging. Critical locations have been
identified for construction W1. These also apply to
this construction.
Other areas where there is a risk of significant
thermal bridging include:
Junctions with solid party walls and partitions
Internal partition or party walls of solid dense
concrete blockwork can create significant thermal
bridge effects at junctions with single leaf masonry
external walls.
Junctions with intermediate floors
The external walls in the floor space of intermediate
floors should be insulated and protected against
vapour movement. Along the wall running parallel to
the joists, insulation can be placed between the last
joist and the wall. Where the joists are perpendicular
to the wall, the insulation and vapour control layer
should be continuous through the intermediate floor
space and should be carefully cut to fit around the
joist ends.
Stairs, cupboards and other fittings supported on
or abutting the external wall
Insulation should be carried through behind such
fittings.
Ducts, e.g. Soil and vent pipe ducts, against
external walls
Insulation should be continuous at all such ducts, i.e.
the insulation should be carried through on either
the external or internal side of such ducts. Where
the insulation is on the external side, particular care
should be taken to prevent ingress of cold external
air where ducts etc. penetrate the insulation.
FLOOR CONSTRUCTIONS
B.7.1 Construction F1: Ground floor :
concrete slab-on-ground. Insulation under
slab or under screed
For continuous and uniform insulation under the full
ground floor area, the insulation thickness required
to achieve prescribed U-values for slab-on-ground
floors are given below. These tables apply whether
the insulation is located under the slab or under the
screed.
Diagram B15
Para. B.7.1
Concrete slab-on-ground floor, insulation
under slab
Concrete screed
(optional)
Concrete floor slab
Insulation
Damp proof membrane. Where radon
barrier required, ensure correct detailing
to prevent passage of radon gas into
dwelling - See TGD C.
Table B18 allows estimation of the U-value of an
insulated floor from the ratio of the length of
exposed perimeter to floor area and the thermal
resistance of the applied insulation. Table B19 gives
the thickness of insulation required to achieve a
given U-value when the ratio of exposed perimeter
to floor area and the thermal conductivity of the
material is known. Both tables are derived for
uniform full-floor insulation, ground conductivity of
2.0 W/m2K and full thickness of walls taken to be 0.3m.
Installation guidelines and precautions
The insulation may be placed above or below the
dpm/radon barrier. The insulation should not absorb
moisture and, where placed below the dpm/radon
barrier, should perform well under prolonged damp
conditions and should not be degraded by any
waterborne contaminants in the soil or fill.
The insulation should have sufficient load-bearing
capacity to support the floor and its loading.
The insulation is laid horizontally over the whole
area of the floor. Insulation boards should be tightly
butted, and cut to fit tightly at edges and around
service penetrations.
Diagram B16
Para. B.7.1
Concrete slab-on-ground floor, insulation
under screed
Screed
Insulation
Damp proof
membrane
Concrete floor slab
Where radon barrier required, ensure
correct detailing to prevent passage of
radon gas into dwelling - See TGD C.
57
Table 18: U-value of insulated ground floor as a function of floor area, exposed
perimeter and thermal resistance of added insulation (Uins).
Exposed Perimeter/Area
(P/A)
(m-1)
Thermal Resistance of Added Insulation
[Rins] (m2K/W)
0.75
1.0
1.25
1.5
1.75
2.0
2.25
2.5
2.75
3.0
3.5
4.0
1.00
0.66
0.57
0.50
0.44
0.40
0.36
0.33
0.31
0.28
0.27
0.23
0.21
0.80
0.62
0.54
0.47
0.42
0.38
0.35
0.32
0.30
0.28
0.26
0.23
0.21
0.90
0.64
0.70
0.59
0.60
0.57
0.50
0.53
0.40
0.48
0.30
0.43
0.20
0.35
0.55
0.52
0.50
0.47
0.43
0.39
0.32
0.48
0.43
0.46
0.41
0.44
0.40
0.42
0.38
0.39
0.36
0.35
0.32
0.30
0.28
Table B19 Concrete slab-on-ground floors:
Insulation thickness required for Uvalue of 0.25 W/m2K.
Total
Thickness of
insulation
(mm)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
10
64
88
100
110
116
120
123
126
128
8
56
77
88
96
101
105
108
110
112
7
48
66
75
82
87
90
93
94
96
6
40
55
63
69
72
75
77
79
80
5
32
44
50
55
56
60
62
63
64
U-Value of construction (W/m2K)
Care should be taken to prevent damage or
dislodgement of insulation during floor laying. If the
dpm is placed below the insulation, the joints
between insulation boards should be taped to
prevent wet screed from entering when being
poured. If the slab/screed is power-floated, the
exposed edges of perimeter insulation should be
protected during power-floating, e.g. by boards, or
58
0.39
0.37
0.36
0.35
0.33
0.30
0.26
0.36
0.34
0.33
0.32
0.30
0.28
0.24
0.33
0.31
0.31
0.30
0.28
0.26
0.23
0.30
0.29
0.28
0.27
0.26
0.24
0.22
0.28
0.27
0.27
0.26
0.25
0.23
0.21
0.26
0.25
0.25
0.24
0.23
0.22
0.20
0.23
0.23
0.22
0.22
0.21
0.20
0.18
0.21
0.20
0.20
0.19
0.19
0.18
0.16
the areas close to the edge of the floor should be
hand trowelled.
Thermal bridging at floor-wall junctions should be
minimised.
With cavity walls, thermal bridging via the inner leaf
is difficult to avoid, but adequate provision to limit it
should be made.
B.7.2 Construction F2: Ground floor :
suspended timber floor, insulation
between joists.
Diagram B17
Para. B.7.2
Suspended timber floor with quilt insulation
Timber flooring
Insulation
between joists
Ventilated
subfloor
Note: Where radon barrier required,
ensure correct detailing to prevent passage
of radon gas into dwelling - See TGD C.
Diagram B18
Para. B.7.2
Suspended timber floor with rigid or
semi-rigid board insulation
Timber flooring
Insulation
between joists
Ventilated
subfloor
Note: Where radon barrier required,
ensure correct detailing to prevent passage
of radon gas into dwelling - See TGD C.
Table B20 Suspended timber ground floors:
Insulation thickness required for
U-value of 0.25 W/m2K.
Total
Thickness of
insulation
(mm)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
39
96
117
128
135
139
143
146
148
150
35
87
106
116
122
126
129
132
134
135
31
77
94
103
109
113
116
118
120
121
U-Value of construction
0.025
0.020
27
68
83
91
96
99
102
104
105
107
23
58
71
78
82
86
88
89
91
92
(W/m2K)
This table is derived for:
Suspended floor consisting of 20 mm timber
flooring (λ = 0.13) on timber joists (λ = 0.13), with
insulation between the joists. Ventilated sub-floor
space underneath. (See Diagrams B17 and B18).
A fractional area of timber thermal bridging of 11%
is assumed.
Installation guidelines and precautions
Where mineral wool quilt insulation is used, the
insulation is supported on polypropylene netting or a
breather membrane draped over the joists and held
against their sides with staples or battens. The full
thickness of insulation should extend for the full
width between joists. Insulation should not be
draped over joists, but cut to fit tightly between
them.
Alternatively, rigid or semi-rigid insulation boards,
supported on battens nailed to the sides of the
joists, may be used.
Thermal bridging, and air circulation around the
insulation from the cold vented air space below,
should be minimised. The insulation should fit tightly
against the joists and the flooring above. Careful
placement of supporting battens (or staples) is
required to achieve this. At floor-wall junctions the
insulation should extend to the walls. The space
between the last joist and the wall should be packed
with mineral wool to the full depth of the joist.
Where internal wall insulation is used, the floor and
59
wall insulation should meet. Where cavity insulation
is used, the floor insulation should be turned down
on the internal face and overlap the cavity insulation,
or insulating blocks used in the wall at this level.
Cross-ventilation should be provided to the subfloor space to remove moisture.
Water pipes in the sub-floor space should be
insulated to prevent freezing.
B.7.3 Construction F3: Ground floor :
suspended concrete floor
Diagram B19
Para. B.7.3
Suspended reinforced concrete floor,
internally insulated walls
Table B21 Suspended concrete ground floors:
Insulation thickness required for Uvalue of 0.25 W/m2K.
Total
Thickness of
insulation
(mm)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
19
69
87
96
102
106
109
112
114
115
17
60
76
84
89
93
96
98
99
101
14
52
65
72
77
80
82
84
85
86
12
43
54
60
64
67
69
70
71
72
10
35
44
48
51
53
55
56
57
58
U-Value of construction (W/m2K)
This table is derived for floors with:
65 mm screed (λ = 0.41) on insulation on 150 mm cast
concrete (λ= 2.20). Full thickness of walls = 0.3 m, U-value
of sub-floor walls: 2 W/m2K. Height of floor surface above
ground level: 0.3 m. (See Diagrams B19 and B20).
Floor screed
Insulation
Suspended
concrete floor
slab
Diagram B20
Para. B.7.3
Suspended beam and block floor
Floor screed
Insulation
Beam and
block floor
60
Unventilated sub-floor crawl space underneath.
Installation guidance and precautions
If the walls are internally insulated, it is
recommended that the floor insulation be placed
above the floor structure, since it can then connect
with the wall insulation. Thermal bridging at the
floor-wall junction is difficult to avoid when insulation
is placed below the floor structure.
If the walls are cavity insulated, floor insulation can
not connect with wall insulation, so some thermal
bridging is inevitable. It can be minimised by using
insulating blocks for the inner leaf between
overlapping floor and wall insulation. Insulation and
insulating blocks may be either above or below the
floor structure, but above is recommended. This will
allow the use of less dense blocks (of lower thermal
conductivity), since they will not have to support the
weight of the floor. Also, above the structure they
will be above the dpc, where their lower moisture
content will give a lower thermal conductivity than
below the dpc. Heat loss from the floor can be
further reduced by extending the cavity insulation
down to, or below, the lower edge of the suspended
floor.
B.7.4 Construction F4: Exposed floor :
timber joists, insulation between joists
Diagram B21
Para. B.7.4
Exposed timber floor, insulation between joists
Installation guidance and precautions
The flooring on the warm side of the insulation
should have a higher vapour resistance than the
outer board on the cold side. If necessary, a vapour
check should be laid across the warm side of the
insulation. Methods of avoiding thermal bridging at
junctions with internally insulated and cavity insulated
walls are similar to those described for suspended
timber ground floors above.
Timber flooring
Insulation
between joists
Plasterboard
or similar
Table B22 U-values for exposed timber floors,
insulation between timber joists,
plasterboard finish.
Total
Thickness of
insulation
(mm)
100
120
140
160
180
200
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.41
0.35
0.31
0.27
0.25
0.22
0.37
0.32
0.28
0.25
0.22
0.20
0.34
0.29
0.25
0.23
0.20
0.19
0.31
0.26
0.23
0.20
0.18
0.17
0.27
0.23
0.20
0.18
0.16
0.15
U-Value of construction (W/m2K)
This table is derived for floors with:
20 mm timber flooring (λ = 0.13), insulation as specified in
table between timber joists (λ = 0.13) of equal depth, 13 mm
plasterboard (λ = 0.25). The calculations assume a fractional
area of timber thermal bridging of 11%. (See Diagram B21) )
61
B.7.5 Construction F5: Exposed floor :
solid concrete, insulation external
Diagram B22
Para. B.7.5
Exposed concrete floor, external insulation
Floor screed
Concrete floor
Insulation
continued around
edge beam
Table B23 U-values for exposed concrete floors,
external insulation, external render
Total
Thickness of
insulation
(mm)
60
80
100
120
140
160
Thermal conductivity of insulation (W/m K)
0.040
0.035
0.030
0.025
0.020
0.54
0.42
0.35
0.30
0.26
0.23
0.48
0.38
0.31
0.26
0.23
0.20
0.42
0.33
0.27
0.23
0.20
0.18
0.36
0.28
0.23
0.19
0.17
0.15
0.30
0.23
0.19
0.16
0.14
0.12
U-Value of construction (W/m2K)
This table is derived for floors with:
150 mm cast concrete (λ = 1.35), insulation, 20 mm external
render. (See Diagram B22).
Installation guidance and precautions
If the walls are internally insulated, this floor
construction is not recommended. Floor insulation
should instead be located internally in order to
connect with the wall insulation.
With cavity wall insulation, thermal bridging may be
minimised by supporting the external leaf
independently, and continuing the external floor
62
insulation around the edge beam to connect with the
cavity insulation as shown in Diagram B22.
Table B24: Indicative U-values (W/m2K) for
windows, doors and roof windows
The values apply to the entire area of the window
opening, including both frame and glass, and take
account of the proportion of the area occupied by
the frame and the heat conducted through it. If the
U-value of the components of the window (glazed
unit and frame) are known, window U-values may
alternatively be taken from the tables in Annex F of
I.S. EN ISO 10077-1, using the tables for 20% frame
for metal-framed windows and those for 30% frame
for wood or PVC-U framed windows.
When available, the manufacturer's certified U-values
for windows or doors should be used in preference
to the data in this table. Adjustments for roof indows
should be applied to manufacturer's window Uvalues unless the manufacturer provides a U-value
specifically for a roof window.
Table B24 Indicative U-values (W/m2K) for windows, doors and rooflights
Type of frame
Window with wood or PVC-U
frame (use adjustment in Note 1)
6 mm 12 mm
gap
gap
double-glazed, air filled
double-glazed, air filled (low-E, Ân = 0.2, hard coat)
double-glazed, air filled (low-E, Ân = 0.15, hard coat)
double-glazed, air filled (low-E, Ân = 0.1, soft coat)
double-glazed, air filled (low-E, Ân = 0.05, soft coat)
double-glazed, argon filled
double-glazed, argon filled (low-E, Ân = 0.2, hard coat)
double-glazed, argon filled (low-E, Ân = 0.15, hard coat)
double-glazed, argon filled (low-E, Ân = 0.1, soft coat)
double-glazed, argon filled (low-E, Ân = 0.05, soft coat)
triple glazed, air filled
triple-glazed, air filled (low-E, Ân = 0.2, hard coat)
triple-glazed, air filled (low-E, Ân = 0.15, hard coat)
triple-glazed, air filled (low-E, Ân = 0.1, soft coat)
triple-glazed, air filled (low-E, Ân = 0.05, soft coat)
triple-glazed, argon filled
triple-glazed, argon filled (low-E, Ân = 0.2, hard coat)
triple-glazed, argon filled (low-E, Ân = 0.15, hard coat)
triple-glazed, argon filled (low-E, Ân = 0.1, soft coat)
triple-glazed, argon filled (low-E, Ân = 0.05, soft coat)
Windows and doors, single glazed
Solid wooden door
3.1
2.7
2.7
2.6
2.6
2.9
2.5
2.4
2.3
2.3
2.4
2.1
2.1
2.0
1.9
2.2
1.9
1.8
1.8
1.7
2.8
2.3
2.2
2.1
2.0
2.7
2.1
2.0
1.9
1.8
2.1
1.7
1.7
1.6
1.5
2.0
1.6
1.5
1.5
1.4
4.8
3.0
16 or
more
mm gap
2.7
2.1
2.0
1.9
1.8
2.6
2.0
1.9
1.8
1.7
2.0
1.6
1.6
1.5
1.4
1.9
1.5
1.4
1.4
1.3
Window with metal
frame with 4mm
thermal break
(use adjustments in
Note 2)
6 mm 12 mm 16 or
gap
gap
more
mm gap
3.7
3.3
3.3
3.2
3.2
3.5
3.0
3.0
2.9
2.8
2.9
2.6
2.5
2.5
2.4
2.8
2.3
2.3
2.2
2.2
3.4
2.8
2.7
2.6
2.5
3.3
2.6
2.5
2.4
2.2
2.6
2.1
2.1
2.0
1.9
2.5
2.0
1.9
1.9
1.8
5.7
3.3
2.6
2.5
2.4
2.3
3.2
2.5
2.4
2.3
2.1
2.5
2.0
2.0
1.9
1.8
2.4
1.9
1.8
1.8
1.7
63
Notes:
(1) For roof windows with wooden or PVC-U frames apply the following adjustments to U-values:
____________________________________________________________________________________
Wood or PVC-U frame
U-value adjustment for roof window, W/m2K
____________________________________________________________________________________________
Single glazed
+0.3
Double glazed
+0.2
Triple glazed
+0.2
____________________________________________________________________________________
(2) For windows or roof windows with metal frames apply the following adjustments to U-values:
____________________________________________________________________________________
Metal frames
Adjustment to U-value, W/m2K
Window
Roof window
____________________________________________________________________________________
Metal, no thermal break
Metal, thermal break 4 mm
Metal, thermal break 8 mm
Metal, thermal break 12 mm
Metal, thermal break 20 mm
Metal, thermal break 32 mm
(3)
+0.7
+0.3
+0.2
+0.1
0
-0.1
For doors which are half-glazed (approximately) the U-value of the door is the average of the appropriate
window U-value and that of the non-glazed part of the door (e.g. solid wooden door [Uvalue of 3.0
W/m2K] half-glazed with double glazing [low-E, hard coat, argon filled, 6 mm gap, Uvalue of 2.5 W/m2K] has
a resultant U-value of 0.5(3.0+2.5) = 2.75 W/m2K).
Source: DEAP Manual Version 2.1 January 2007
64
+0.3
0
-0.1
-0.2
-0.3
-0.4
Appendix C:
Reference values for calculation of Maximum
Permitted Energy Performance Coefficient (MPEPC) and
Maximum Permitted Carbon Performance Coefficient (MPCPC)
energy performance coefficient (EPC) and carbon
performance coefficient (CPC) respectively for a
dwelling being assessed. These, in turn are compared
to the MPEPC and MPCPC in order to demonstrate
compliance for the dwelling being assessed.
GENERAL
C.1 This Appendix provides a set of reference
values for the parameters of a DEAP calculation,
which are used in connection with establishing an
EPC and CPC for a dwelling for the purposes of
demonstrating compliance with Regulation L2 (a) for
new dwellings. Table C1 is used to define a notional
reference dwelling of the same size, i.e. same floor
area and volume, and with the same area of opaque
fabric elements, i.e. wall, roof and floor, as a dwelling
being assessed. The total external window, rooflight
and door area is taken to be 25% of the dwelling
floor area.
C.3
The main heating system for space and water
heating in the reference dwelling is assumed to be
natural gas, while the secondary system is assumed
to be an open fire. Some 10% of space heating is
assumed to be provided by the secondary heating
method.
C.2
The primary energy consumption and CO2
emissions per unit floor area calculated for this
reference dwelling are used to calculate the primary
Table C1
Reference Values
Element or system
Specifications
Opening areas (windows and doors)
25% of total floor area, or sum of exposed roof and wall
area, whichever is the lesser
The above includes one opaque door of area 1.85 m2,
any other doors are fully glazed
Total floor area, and dwelling volume
Walls
Roof
Floor
Opaque door
Windows and glazed doors
Living area fraction
Shading and orientation
Number of sheltered sides
Same as actual dwelling
U = 0.27 W/m2K
Area : Total wall area including windows and doors to
be the same as actual dwelling
U = 0.16 W/m2K
Area : Total area including any roof windows to be same
as actual dwelling.
U = 0.25 W/m2K
Area : same as actual dwelling
U = 3.0 W/m2K
U = 2.2 W/m2K
Double glazed, low-E hard coat
Frame factor 0.7
Solar energy transmittance 0.72
Light transmittance 0.80
Same as actual dwelling
All glazing oriented E/W; average overshading
2
65
Table C1 (contd...)
Reference Values
Element or system
Allowance for thermal bridging
Specifications
Ventilation system
Natural ventilation with intermittent extract fans
Internal heat capacity category
Air permeability
0.11 x total exposed surface area (W/K)
Medium
Infiltration due to structure = 0.5 ac/h
Chimneys
One
Extract fans
3 for dwellings with floor area greater than 100 m2,
2 for smaller dwellings
Open flues
None
Draught lobby
None
Heating system
Boiler and radiators
water pump in heated space
Primary heating fuel (space and water)
Boiler
Heating system controls
Hot water system
Hot water cylinder
Primary water heating losses
Secondary space heating
Low energy light fittings
66
Mains gas
Seasonal efficiency 78%
room-sealed
fanned flue
Programmer + room thermostat + TRVs
boiler interlock
Stored hot water, heated by boiler
separate time control for space and water heating
120 litre cylinder insulated with 35 mm of factory
applied foam
Primary pipework uninsulated
cylinder temperature controlled by thermostat
Open fire
None
Appendix D:
Thermal Bridging at Junctions and Around
Openings
D.1 This Appendix deals with the assessment of
discrete thermal bridging not taken account of in the
calculation of the U values of plane building
elements, e.g. at junctions and around openings such
as doors and windows. It gives guidance on
•
•
avoidance of mould growth and surface
condensation, and
limiting factors governing additional heat losses.
The guidance is based primarily on “BRE IP 1/06:
Assessing the effects of thermal bridging at junctions and
around openings”.
D.2 Mould Growth and Surface Condensation
The key factor used in assessing the risk of mould
growth or surface condensation in the vicinity of
thermal bridges is the temperature factor (fRsi).
The temperature factor (fRsi) is defined as follows:
The temperature factor (fRsi) is defined as follows:
fRsi = (Tsi – Te) / (Ti – Te)
where:
Tsi = minimum internal surface
temperature,
Te = external temperature, and
Ti = internal temperature.
For dwellings, the value of fRsi should be greater than
or equal to 0.75, so as to avoid the risk of mould
growth and surface condensation. For threedimensional corners of ground floors this value may
be reduced to 0.70, for all points within 10 mm of
the point of lowest fRsi.
D.3 Linear Thermal Transmittance and
Additional Heat Loss
The linear thermal transmittance (ψ) describes the
heat loss associated with a thermal bridge. This is a
property of a thermal bridge and is the rate of heat
flow per degree per unit length of bridge that is not
accounted for in the U-values of the plane building
elements containing the thermal bridge. The linear
transmission heat loss coefficient associated with
non-repeating thermal bridges is calculated as:
HTB = Σ(Lx ψ) (W/m2K)
where L is the length of the thermal bridge over
which ψ applies.
D.4 Calculation procedures
The calculation procedure to establish both
temperature factor (f Rsi) and the linear thermal
transmittance (ψ) is outlined in BRE IP 1/07. Details
should be assessed in accordance with the methods
described in IS EN ISO 10211 Parts 1 and 2. These
calculations of two dimensional or three dimensional
heat flow require the use of numerical modeling
software. To be acceptable, numerical modeling
software should model the validation examples in IS
EN ISO 10211 with results that agree with the stated
values of temperature and heat flow within the
tolerance indicated in the standard for these
examples. Several packages are available that meet
this requirement.
Detailed guidance on decisions regarding specific
input to the modeling software and the
determination of certain quantities from the output
of the software is contained in BRE Report BR 497
Conventions for calculating linear thermal transmittance
and temperature factors. This guidance should be
followed in carrying out modeling work so that
different users of the same software package and
users of different software packages can obtain
correct and consistent results.
Table D1
Target linear thermal
ψ) for
transmittance (ψ
different types of junctions.
Junction detail in external wall
Steel lintel with perforated steel base plate
Sill
Other lintels (including other steel lintels)
Jamb
Ground floor
Intermediate floor within a dwelling
Intermediate floor between dwellings1
Balcony within a dwelling2
Balcony between dwellings1, 2
Eaves (insulation at ceiling level)
Eaves (insulation at rafter level)
Gable (insulation at ceiling level)
Gable (insulation at rafter level)
Corner (normal)
Corner (inverted)
Party wall between dwellings1
Linear
Thermal
Transmittance
(ψ) (W/mK)
0.50
0.04
0.30
0.05
0.16
0.07
0.14
0.00
0.04
0.06
0.04
0.24
0.04
0.09
-0.09
0.06
Note 1: For these junctions, half the value of ψ is applied to
each dwelling
Note 2: Refers to an externally supported balcony (the balcony
slab is not a continuation of the floor slab)
67
D.5 Values of linear thermal transmittance
ψ)
(ψ
Table D1 sets out a set of target values for typical
key thermal bridges encountered in dwellings.
Thermal bridges which are in accordance with those
contained “Accredited Details” (downloadable from
Department of Communities and Local Government
(London)website www. Communities.gov.uk) or the
document “Limiting Thermal Bridging and Air Infiltration
– Acceptable Construction Details” (to be published)
satisfy these target values.
D.6 Treatment of Thermal Bridging in DEAP
calculation
Heat loss through thermal bridging is taken account
of in the DEAP calculation. Two alternative methods
of accounting for heat loss are possible
(a)
Heat loss through thermal bridging can be
accounted for in terms of a fraction (y)
multiplied by the exposed surface area of the
building. Where the linear thermal
transmittance (ψ) of all the construction
details used are known to meet the target
values set out in Table D1, or are shown by
calculation to meet these values, the value of
(y) can be taken as 0.8. Where this is not the
case, but this method of accounting for
thermal bridging is used, the default value of (y)
of is taken to be 0.15.
(b)
Values of ψ can be determined from the
results of numerical modeling, or they can be
derived from measurement. The linear
transmission heat loss coefficient (H TB) can
then be calculated directly and included in the
DEAP calculation.
The approach adopted is fully explained in the DEAP
manual.
68
Appendix E:
Achieving Compliance with
respect to EPC and CPC
The following table gives a set of
E1
specifications which are calculated to achieve
compliance for a typical 126 m 2 semi-detached
house. Compliance with this requirement could also
be achieved by a number of other combinations of
measures.
Table E1
Example Dwellings
Element or system
Dwelling size and shape
Opening areas (windows and doors)
Walls
Roof
Floor
Opaque door
Windows and glazed doors
Specifications
Semi-detached house, two-storey
Overall internal dimensions: 7 m wide x 9 m deep x 5.1
m high
Total floor area 126 m2
Rectangular shape with no irregularities
25% of total floor area
The above includes one opaque door of area 1.85 m2,
any other doors are fully glazed
U = 0.25 W/m2K
e.g. cavity wall with 100 mm insulation of conductivity
0.03 W/m K in cavity
U = 0.15 W/m2K
e.g. 270 mm insulation of conductivity 0.04 W/m K,
between and over ceiling joists
U = 0.20 W/m2K
e.g. Slab-on-ground floor with 100 mm insulation of
conductivity 0.03 W/m K
U = 3.0 W/m2K
Double glazed, low E (En = 0.05, soft coat) 16mm gap,
argon filled, wood frames
(U = 1.7 W/m2K, solar transmittance = 0.63)
Living area fraction
25% of total floor area
Number of sheltered sides
2
Internal heat capacity category
Medium
Shading and orientation
Allowance for thermal bridging at element junctions
Ventilation system
Air permeability
Chimneys
Open flues
Extract fans
All glazing oriented E/W; average overshading
0.08 x total exposed surface area (W/m2K)
Natural ventilation with intermittent extract fans
Infiltration due to structure = 0.4 ac/h
None
None
3
69
Table E1 (contd...)
Example Dwelling
Element or system
Specifications
Primary heating fuel (space and water)
Mains gas
Draught lobby
Heating system
Boiler
Heating system controls
Hot water system
Primary water heating losses
Secondary space heating
Low energy light fittings
E.2
The standardized primar y energy
consumption and CO2 emissions for space heating,
water heating, ventilation and lighting for this
dwelling, as calculated by DEAP, are given in Table E2,
expressed per m2 of floor area per annum. The table
shows that the calculated EPC just complies with the
MPEPC requirement of 0.60, and the CPC complies
with the MPCPC requirement of 0.69 with a margin
to spare.
If the boiler ran on heating oil rather than mains gas,
and the secondary heater on bottled LPG, with the
same efficiencies as above, the dwelling would be
slightly outside compliance. Compliance may be
achieved, for example, by improving the roof U-value
from 0.15 to 0.13. The results following this change
are also shown in the Table E2.
70
None
Boiler and radiators
water pump in heated space
Mains gas condensing boiler, seasonal efficiency 90%,
room-sealed, fanned flue
Programmer + room thermostat + TRVs,
boiler interlock
Solar water heating system with flat plate collector of
aperture area = 3.8 m2, η0 = 0.8, a1 = 5.0 W/m2 K, facing
SE/SW at 30 degrees and unshaded, twin coil cylinder
250 litre with 75 mm insulation
Remainder of demand met by space heating boiler,
separate time control for space and water heating,
cylinder temperature controlled by thermostat
Insulated primary pipework between boiler and cylinder
Gas fire, closed front, fan assisted, balanced flue –
efficiency 72%
75%
Table E2 Example Dwelling - Results
Dwelling
heated by
mains gas
Primary energy
[kWh/m2 yr]
CO2 emissions
[kg/m2 yr]
EPC
CPC
90
Dwelling
heated by oil
(with
secondary
heating by
LPG)
90
18
22
0.60
0.60
0.55
0.68
Standards and Other References
Standards referred to:
I.S. 161: 1975 Copper direct cylinders for domestic
purposes.
I.S. 325-1: 1986 Code of Practice for use of masonry
- part 1: Structural use of unreinforced masonry.
I.S. EN 1745: 2002 Masonry And Masonry Products Methods for determining Design Thermal Values.
I.S. EN ISO 6946: 1997 Building components and
building elements –Thermal resistance and thermal
transmittance – Calculation method Amd 1 2003.
I.S. EN ISO 8990: 1997 Thermal insulation –
Determination of steady-state thermal transmission
properties – Calibrated and guarded hot box.
I.S. EN ISO 10077-1: 2001 Thermal performance of
windows, doors and shutters – Calculation of
thermal transmittance – Part 1: simplified method.
I.S. EN 10077-2: 2000 Thermal performance of
windows, doors and shutters – Calculation of
thermal transmittance – Part 2: Numerical methods
for frames.
I.S. EN ISO 10211-1: 1996 Thermal bridges in
building construction – heat flows and surface
temperatures. Part 1 general calculation methods.
I.S. EN ISO 10211-2: 2001 Thermal bridges in
building construction – heat flows and surface
temperatures. Part 2 linear thermal bridges.
I.S. EN ISO 10456: 2000 Building materials and
products - procedures for determining declared and
design thermal values.
I.S. EN 12524: 2000 Building materials and products –
Hygrothermal properties – Tabulated design values.
I.S. EN ISO 12567-1: 2001 Thermal performance of
windows and doors – Determination of thermal
transmittance by hot box method – Part 1: Complete
windows and doors.
I.S. EN ISO 13370: 1999 Thermal performance of
buildings – Heat transfer via the ground – Calculation
methods.
I.S. EN ISO 13789: 2000 Thermal Performance of
Buildings – Transmission Heat Loss Coefficient –
Calculation Method.
I.S. EN 13829: 2000 Thermal Performance of
Buildings: Determination of air permeability of
buildings: fan pressurisation method.
BS 747: 2000 Reinforced bitumen sheets for roofing
– Specification.
BS 1566 Part 1: 2002 Copper indirect cylinders for
domestic purposes, open vented copper cylinders.
Requirements and test methods.
BS 5422 : 2001 Method for specifying thermal
insulating materials for pipes, tanks, vessels, ductwork
and equipment (operating within the temperature
range - 400C to + 7000C).
BS 8206 Part 2: 1992 Lighting for buildings. Code of
practice for daylighting.
Other Publications referred to:
BRE Digest 465, U-values for light steel frame
construction, BRE, 2002.
BRE Information Paper 1/06 Assessing the effects of
thermal bridging at junctions and around openings,
BRE, 2001.
BRE Information Paper 10/02, Metal cladding:
assessing the thermal performance of built-up
systems using ‘Z’ spacers, BRE, 2002
BRE Report BR 262, Thermal Insulation: avoiding
risks, BRE, 2001
BRE Report BR 364, Solar shading of buildings, BRE,
1999
BRE Report BR 443, Conventions for U-value
Calculations, BRE, 2002.
BRE Report BR 497, Conventions for calculating
linear thermal transmittance and temperature
factors, BRE, 2007
CIBSE Guide A: Environmental Design - Section 3:
Thermal Properties of Buildings and Components,
CIBSE, 1999
CIBSE TM 23: Testing Buildings for Air Leakage,
CIBSE, 2000
Chris Knights and Nigel Potter, Airtightness Testing
for New Dwellings, A BSRIA Guide ,BSRIA, 2006
Domestic Energy Assessment Procedure (DEAP) SEI
2006 (www.sei.ie)
Good Practice Guide 268, Energy efficient ventilation
in dwellings – a guide for specifiers, 2006
Home-heating Appliance Register of Performance
(HARP) database, SEI (www.sei.ie/harp).
Heating and Domestic Hot Water Systems for
dwellings – Achieving compliance with Part L (to be
published).
Limiting Thermal Bridging and Air Infiltration –
Acceptable Construction Details (to be published)
MCRMA Technical Paper No. 14, Guidance for the
design of metal roofing and cladding to comply with
Approved Document L2:2001, The Metal Cladding
and Roofing Manufacturers Association, 2002
SCI Technical Information Sheet 312, Metal cladding:
U-value calculation - assessing thermal performance
of built-up metal roof and wall cladding systems using
rail and bracket spacers, The Steel Construction
Institute, 2002
71
SI. No. 260 of 1994, European Communities
(Efficiency requirements for hot water boilers fired
with liquid or gaseous fuels) Regulations, 1994, The
Department of Transport, Energy and
Communications, 1994
Other Useful Standards and Publications
IS EN 14785: 2006 Residential space heating
appliances fired by wood pellets - requirements and
test methods
I.S. EN 303-5: 1999 Heating boilers - heating boilers
for solid fuels, hand and automatically stoked,
nominal heat output of up to 300 kw - terminology
requirements, testing and marking
Pr EN 15270: Pellet burners for small heating boilers
- Definitions, requirements, testing, marking
(Expected to be adopted as IS EN 15270 in 2008)
IS EN 12975-1: 2006 Thermal solar systems and
components - solar collectors - part 1: general
requirements
IS EN 12975-2: 2006 Thermal solar systems and
components - solar collectors - part 2: test methods
IS EN 12976-1: 2006 Thermal solar systems and
components - factory made systems - part 1: general
requirements
IS EN 12976-2 : 2006 Thermal solar systems and
components - factory made systems - part 2: test
methods
IS ENV 12977-1: 2001 Thermal solar systems and
components - custom built systems - part 1: general
requirements
IS ENV 12977-2 : 2001 Thermal solar systems and
components - custom built systems - part 2: test
methods
ISO 9806-1: 1994 Test methods for solar collectors - part 1: thermal performance of glazed liquid heating
collectors including pressure drop
ISO 9806-2: 1995 Test methods for solar collectors - part 2: qualification test procedures
ISO 9806-3: 1995 Test methods for solar collectors - part 3: thermal performance of unglazed liquid
heating collectors (sensible heat transfer only)
including pressure drop
IS EN 14511-1: 2004 Air conditioners, liquid chilling
packages and heat pumps with electrically driven
compressors for space heating and cooling - part 1:
terms and definitions
72
IS EN 14511-2 :2004 Air conditioners, liquid chilling
packages and heat pumps with electrically driven
compressors for space heating and cooling - part 2:
test conditions
IS EN 14511-3: 2004 Air conditioners, liquid chilling
packages and heat pumps with electrically driven
compressors for space heating and cooling - part 3:
test methods
IS EN 14511-4: 2004 Air conditioners, liquid chilling
packages and heat pumps with electrically driven
compressors for space heating and cooling - part 4:
requirements
I.S. EN 12664: 2001 Thermal performance of building
materials and products – Determination of thermal
resistance by means of guarded hot plate and heat
flow meters method – Dry and moist products of
low and medium thermal resistance.
I.S. EN 12667: 2001 Thermal performance of building
materials and products – Determination of thermal
resistance by means of guarded hot plate and heat
flow meters method – Products of high and medium
thermal resistance.
I.S. EN 12828: 2003 Heating systems in buildings design for water-based heating systems.
I.S. EN 12939: 2001 Thermal performance of building
materials and products – Determination of thermal
resistance by means of guarded hot plate and heat
flow meters method – Thick products of high and
medium thermal resistance.
03/03/2008
08:42
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Building Regulations 2007
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Conservation of Fuel
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Building
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Te c h n i c a l
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