BRA Guide to Flammable Refrigerants Issue 1 Oct 12

BRA Guide to Flammable Refrigerants Issue 1 Oct 12
Guide to
Flammable Refrigerants
Issue 1, October 2012
Supported by the HEVAC Air Conditioning Group and the Heat Pump Association
Guide to Flammable Refrigerants
This Guide has been prepared by Cool Concerns Ltd at the request of the Council of the
British Refrigeration Association (BRA) because of the increase in the application of
flammable refrigerants such as hydrocarbons, HFOs and flammable HFCs. It provides
impartial information about the flammability issues associated with these refrigerants to
end users, specifiers, building owners, manufacturers and contractors. It is an introduction
to flammable refrigerants and signposts where more detailed information can be obtained if
necessary.
Scope of this Guide:



Hydrocarbons (HCs);
Hydrofluoroolefins (HFOs);
Flammable hydrofluorocarbons (HFCs).
Ammonia (R717) is not included in this Guide. Section 10 shows where there is detailed
information about R717.
This guide applies to the use of flammable refrigerants in new, specially designed systems.
Existing systems using non-flammable refrigerants must not be retrofitted to flammable
refrigerants.
At the time of publication many of the standards referred to in this document are in revision.
This includes EN378, ISO 5149 and ISO 817. The text indicates which versions are referenced
in this document. Refer to the British Standards Institute for details of revisions.
For full information …
This Guide is an introduction to flammable refrigerants. In many instances more detailed
information is essential.
It is recommended that the application and installation of systems using flammable
refrigerants are checked, for example by an independent expert. This should include
confirmation that:




The system has been produced to specification and to the relevant regulations and
standards;
The system charge does not exceed the limits appropriate for its location;
Sources of ignition are not located in a potentially flammable zone around a system
charged with a flammable refrigerant;
Appropriately trained and qualified engineers work on the equipment.
End users should be made aware that systems are charged with a flammable refrigerant.
Where applicable, information about the minimum room size the equipment can be located
in and the potentially flammable zone extent around the equipment should be provided.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 1
Table of Contents
1. Introduction ........................................................................................................................... 4
Helpful definitions ................................................................................................................. 4
2. Regulations, Standards and Codes of Practice ...................................................................... 6
3. Transport of Flammable Gases in Cylinders and Equipment ................................................ 8
Transport of cylinders by road .............................................................................................. 8
Transport of charged systems ............................................................................................... 8
4. Maximum Flammable Gas Charge Size ............................................................................... 10
Comfort cooling / heating applications ............................................................................... 10
Non comfort cooling / heating applications ........................................................................ 10
Special machine rooms........................................................................................................ 14
5. Systems / Applications ........................................................................................................ 15
6. Overview of Design.............................................................................................................. 17
7. Overview of Manufacture ................................................................................................... 19
8. Overview of Service ............................................................................................................. 20
Tools and equipment........................................................................................................... 20
Procedures........................................................................................................................... 20
9. Training ............................................................................................................................... 21
10. Sources of Further Information ......................................................................................... 22
Appendix 1, Example Label for a Flammable Refrigerant System........................................... 23
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 2
Disclaimer
© Federation of Environmental Trade Associations Ltd 2012
All rights reserved. Apart from any fair dealing for the purposes of private study or research
allowed under applicable copyright legislation, no part of the publication may be
reproduced, stored in a retrieval system, or transmitted in any form by any means,
electronic, mechanical, photocopying, recording or otherwise, without the prior permission
of the Federation of Environmental Trade Associations, 2 Waltham Court, Milley Lane, Hare
Hatch, Reading, Berkshire RG10 9TH.
FETA uses its best efforts to promulgate Standards and Guidelines for the benefit of the
public in the light of available information and accepted industry practices but do not intend
such Standards and Guidelines to represent the only methods or procedures appropriate for
the situation discussed. FETA does not guarantee, certify or assure the safety or
performance of any products, components, or systems tested, installed or operated in
accordance with FETA's Standards or Guidelines or that any tests conducted under its
Standards or Guidelines will be non-hazardous or free from risk.
FETA, and the individual contributors, disclaims all liability to any person for anything or for
the consequences of anything done or omitted to be done wholly or partly in reliance upon
the whole or any part of the contents of this booklet.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 3
1. Introduction
The trend towards the use of flammable refrigerants has increased over the last decade.
Hydrocarbons are now used widely in small integral systems as well as in some larger
systems. HFOs such as R1234ze have lower flammability and are being introduced in trial
applications. Flammable HFCs such as R32 are also starting to be used.
Helpful definitions
HC = hydrocarbon – naturally occurring substances containing only hydrogen and carbon;
HFC = hydrofluorocarbon – halocarbon containing only hydrogen, fluorine and carbon;
HFO = hydrofluoroolefin – halocarbon containing only hydrogen, fluorine and unsaturated
carbon;
Refrigerants are classified according to their flammability and toxicity. “A” classification
indicates low toxicity (“B” is high toxicity). The numbers 1, 2 or 3 following the A or B
indicate the degree of flammability.
The safety classifications below are defined in ISO817:2009 1 and are also used in EN3781:2008 A2:20122.
Safety
classification
Lower
Flammability
level, % in air
by volume
Heat of
combustion,
J/kg
Flame propagation
No flame propagation when tested at 60OC and 101.3 kPa
A1
A2, lower
flammability
> 3.5
< 19,000
A2L, lower
flammability,
proposed sub
classification
> 3.5
< 19,000
A3, higher
flammability
≤ 3.5
≥ 19,000
Exhibit flame propagation when
tested at 60OC and 101.3 kPa
Exhibit flame propagation when
tested at 60OC and 101.3 kPa and have
a maximum burning velocity of ≤ 10
cm/s when tested at 23OC and 101.3
kPa
Exhibit flame propagation when
tested at 60OC and 101.3 kPa
Note – it is proposed to include the A2L safety classification in revisions of EN 378 and ISO
817. It is already used in ASHRAE standards (American Society of Heating, Refrigeration and
Air Conditioning Engineers) and is in de facto use, so it is included in this document. To
highlight that it is not yet in the standards referenced here it will be shown as “A2L
(proposed)” in the text of this document.
1
ISO817:2009 Refrigerants – Definitions and safety classification. Note that the A2L classification is
not yet adopted – it is in the current proposed revision of ISO817.
2
EN378-1:2008+A2:2012, Refrigerating systems and heat pumps – Safety and environmental
requirements, Part 1 – Basic requirements, definitions, classification and selection criteria
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 4
The table below lists the most common flammable refrigerants. There are many other
flammable HFCs listed in various standards, but they are not used in the UK so have not
been listed below.
Refrig.
BP 1
Safety
group 2
LFL,
kg/m3 3
LFL, % 4
PL, kg/m3
GWP 6
0.011
3
HC
R600a
HC
R290
HC
R1270
HC
Care 30 7
HC
Care 50 7
HFO
R1234yf
-12
A3
0.038
1.8
Auto
ignition
temp, OC
460
-42
A3
0.038
2.1
470
0.008
3
-48
A3
0.047
2.7
455
0.008
3
-23 / -32
A3
0.041
2.0
460
3
-43 / -49
A3
0.038
2.0
460
3
-29.4
6.5
405
HFO
R1234ze 7
HFC
R32
-19
5.8 8
14.4
288 to
293
648
0.061
550
HFC
R143a
HFC
R152a
-47
A2
0.299
A2L
(proposed)
A2L
(proposed)
A2
0.307
A2L
(proposed)
A2
0.282
8.2
750
0.056
4300
-25
A2
4.8
455
0.027
120
-51.7
0.13
5
0.06
4
6
1. BP is the boiling point at atmospheric pressure. For zeotropic blends it is the saturated
liquid (bubble) / saturated gas (dew) temperatures.
2. The safety group is as listed in EN378-1.
3. LFL (kg/m3) is the Lower Flammability Limit as listed in EN378-1.
4. LFL (%) is the Lower Flammability Limit as listed in ISO817:2009.
5. PL is the Practical Limit as listed in EN378-1.
6. GWP is the Global Warming Potential as listed in EN378-1.
7. These refrigerants are not listed in the current versions of EN378 or ISO817. The
information is from the refrigerant suppliers.
8. HFO1234ze does not exhibit flame limits under standard test conditions, but it does at
temperatures above 30OC. The LFL stated is at 60OC.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 5
2. Regulations, Standards and Codes of Practice
There are regulations and standards which cover the use of flammable refrigerants. These,
for example, cover the design of systems and components, specify maximum refrigerant
charge sizes, specify how cylinders and charged systems should be transported and outline
the required competence of engineers.
ATEX is the name commonly given to the legal requirements for controlling explosive
atmospheres and the suitability of equipment and protective systems used in them.

ATEX 95 (94/9/EC) covers the design of equipment and protective systems intended
for use in potentially explosive atmospheres.

ATEX 137 (99/92/EC) covers the minimum requirements for improving the safety
and health protection of workers potentially at risk from explosive atmospheres. It
applies, for example, to service engineers working on HC systems. DSEAR
(Dangerous Substances and Explosive Atmosphere Regulations) is the UK
implementation of ATEX 137. It also covers oxy acetylene brazing in the work place.
EN378 (see below) is not harmonised with the ATEX directive and it does not specify that
ATEX applies, but it does reference ATEX harmonised standards such as EN60079.
System designers and manufacturers should follow the principles of ATEX to assess whether
the risk of an explosive atmosphere can occur. In the case of HC refrigerant more detailed
information is provided in the BRA Code of Practice - Design and Manufacture of
Refrigerated Cabinets Running on Hydrocarbon Refrigerants. Although this Code covers
small systems, much of the information is applicable to a wider range of systems.
The following documents include guidance on systems using flammable refrigerants.
Document
Title
ISO817:2005
Refrigerants -- Designation system
EN378-1:2008
A2:2012
Refrigerating systems and heat
pumps – Safety and environmental
requirements, Basic requirements,
definitions, classification and
selection criteria
Refrigerating systems and heat
pumps – Safety and environmental
requirements, Design,
construction, testing, marking and
documentation
Refrigerating systems and heat
pumps – Safety and environmental
requirements, Installation site and
personal protection
EN378-2:2008
A2:2012
EN378-3:2008
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Guidance (relevant to flammable
refrigerants)
An unambiguous system for
numbering refrigerants. It includes
safety classifications (A1, A2, A3).
Practical limit
Maximum charge sizes
High pressure protection
Ventilated enclosures
Machinery rooms
Refrigerant detectors
Page | 6
EN378-4:2008
A2:2012
EN600790:2009
EN60079-101:2009
EN6007914:2008
EN6007915:2010
EN60335-224:2010
EN60335-240:2003
EN60335-289:2010
ADR
RID
IoR A2 and A3
Code
BRA HC
Cabinet Code
Refrigerating systems and heat
pumps – Safety and environmental
requirements, Operation,
maintenance, repair and recovery
Explosive atmospheres –
Equipment – general requirements
Explosive atmospheres –
Classification of areas – explosive
gas atmospheres
Explosive atmospheres – Electrical
installations design, selection and
erection
Explosive atmospheres –
Equipment protection by type of
protection “n”
Household & similar electrical
appliances – Safety
Part 2-24: Particular requirements
for refrigerating appliances, icecream appliances & ice-makers
Household & similar electrical
appliances – Particular
requirements for electrical heat
pumps, air conditioners and
dehumidifiers
Household & similar electrical
appliances – Safety
Part 2-89: Particular requirements
for commercial
refrigerating appliances with an
incorporated or
remote refrigerant condensing unit
or compressor
European Agreement concerning
the International Carriage of
Dangerous Goods by Road
Regulations concerning the
international carriage of dangerous
goods by rail
Institute of Refrigeration Safety
Code of Practice for Refrigerating
Systems utilising A2 and A3
refrigerants
British Refrigeration Association
Design and Manufacture of
Refrigerated Cabinets Running on
Hydrocarbon Refrigerants
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Repairs to flammable refrigerant
systems
Competence of personnel working on
flammable refrigerant systems
Categorisation of flammable gases
Classification of equipment
Zones
Zones and classification of equipment
Leak simulation testing
Air flow requirements
Location of sources of ignition
Wiring
Electrical equipment and enclosures
for use in potentially flammable
areas
Labelling of electrical equipment
Systems with less than 150 g
flammable refrigerant charge.
Design, application and servicing of
AC systems using flammable
refrigerants.
Systems with less than 150 g
flammable refrigerant charge, leak
simulation testing for area
classification.
Transport of flammable gases in
systems or equipment by road
Transport of flammable gases in
systems or equipment by rail
General guidance
Information for designers on the safe
application of HC refrigerants in
refrigerated cabinets such as display
cases.
Page | 7
3. Transport of Flammable Gases in Cylinders and Equipment
This section covers both the transport of flammable gases in cylinders, for example by the
service contractor, and the transport of refrigeration and air conditioning systems which are
charged with flammable refrigerant, for example by the equipment manufacturer. The most
common requirements of service companies and manufacturers are covered below.
Transport of cylinders by road
The ADR Regulation 20073 is a European agreement which standardises transport
regulations across Europe. ADR applies to everyone carrying gases in the course of his or
her work in a vehicle. Cylinders are assigned a number of transport units dependent on
capacity or the maximum weight of product. If the total load is below the ADR threshold
basic legal safety regulations apply, above the threshold the full ADR legislation applies.
The threshold depends on the products being transported, but most service companies will
not exceed the threshold. The basic legal safety requirements for a load below the ADR
threshold (small load exemptions) carried in a closed vehicle are as follows:





Drivers should be aware of the hazards of the products, how to safely handle them,
emergency procedures and the use of fire fighting equipment;
Vehicles should be well ventilated;
One 2kg fire extinguisher should be carried;
Cylinder valves should be closed and adaptors disconnected;
Cylinders should be secure and clearly labelled.
It is recommended that vehicles are marked with the appropriate warning diamond (the red
flammable gas diamond for flammable refrigerants) and that information about the load is
carried, for example in the form of a TREMCard (Transport Emergency Card – available from
the refrigerant supplier).
Transport of charged systems
Much of this information has been provided by Business Link4.
Transport of charged systems by road
Part 3 (Dangerous goods list, special provisions and exemptions related to limited and
excepted quantities) of the ADR Regulation applies to the transport of systems charged with
flammable refrigerant.
Flammable liquefied gases shall be contained within refrigerating machine components.
These components shall be designed and tested to at least three times the working pressure
of the machinery. The refrigerating machines shall be designed and constructed to contain
the liquefied gas and preclude the risk of bursting or cracking of the pressure containing
components during normal conditions of carriage. Refrigerating machines and refrigerating
machine components are not subject to the requirements of ADR if they contain less than
3
4
European Agreement concerning the International Carriage of Dangerous Goods by Road
Business Link is an online government resource for businesses, see section 10
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 8
12 kg of gas. The maximum number of packages in any vehicle or container should not
exceed 1000.
Excepted packages should be marked with the label,
left (minimum size 100mm x 100mm)
* The label number
** The name of the consignor or of the consignee
shall be shown in this location if not shown
elsewhere on the package.
Specialist advice should be sought regarding the
detail of ADR and requirements for documentation.
Transport of charged systems by sea
The International Maritime Dangerous Goods (IMDG) code provides guidance on
transporting dangerous goods by sea. Information about the IMDG code is provided on the
International Maritime Organization (IMO) website (see section 10).
The IMDG code is used by operators transporting dangerous goods on journeys involving a
sea crossing. This includes ferry services. In the UK the Merchant Shipping (Dangerous Goods
and Marine Pollutant) Regulations 1997 and the Dangerous Substances in Harbour Areas
Regulations 1987 also apply.
Transport of charged systems by rail
The carriage of dangerous goods by rail is governed by Appendix C of the Convention
Covering International Carriage by Rail - International Carriage of Dangerous Goods by Rail.
The Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations
2009 (as amended) apply in Great Britain.
Transport of charged systems by air
The International Civil Aviation Organization's (ICAO) Technical Instructions are an
internationally agreed set of provisions governing the requirements for transporting
dangerous goods by air. The International Air Transport Association (IATA, see section 10)
publishes the Dangerous Goods Regulations in accordance with the ICAO technical
instructions. Publications and more information on the carriage of dangerous goods by air is
available on the Civil Aviation Authority website (see section 10).
Some airlines and countries have their own derogations, known as State and Operator
Variations. The IATA Dangerous Goods Regulations provides more information.
Acceptance of airfreight depends on individual carriers and specific advice should be taken
before considering airfreight of appliances containing flammable refrigerants. Guidance can
be found on the IATA web site, see section 10.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 9
4. Maximum Flammable Gas Charge Size
The amount of flammable refrigerant which can be used in systems is restricted and
depends on a number of factors:



Location of equipment, e.g. below or above ground level;
Occupancy of area being cooled, e.g. unrestricted access by the public or authorised
access only;
Type of system, e.g. direct expansion or secondary / refrigeration or air conditioning.
The limits are different for comfort cooling / heating and non comfort cooling / heating
applications.
Systems with less than 150 g flammable refrigerant charge can be located anywhere, though
it should be noted that ATEX applies to all commercial premises regardless of charge size, so
the potentially flammable zone should still be assessed (see section 6 for more information).
Comfort cooling / heating applications
For comfort cooling / heating applications the maximum charge is based on the LFL of the
refrigerant, the floor area and the height of the indoor unit:
M = 2.5 x LFL1.25 x h x A
M = max charge, kg
LFL = lower flammability limit, kg/m3
h = height of unit, m, (0.6 for floor mounted, 1.0 for window, 1.8 for wall, 2.2 for ceiling)
A = floor area, m2
Examples
A split AC system with a ceiling mounted indoor unit in a room 9 m long by 5.5 m wide using
R290:
M = 2.5 x 0.0381.25 x 2.2 x (9 x 5.5) = 0.65 kg
As above but using R32:
M = 2.5 x 0.3071.25 x 2.2 x (9 x 5.5) = 8.84 kg
Non comfort cooling / heating applications
Two limits are specified:


The “practical limit” based on room size;
The “overall maximum charge” based on system location and occupancy.
Whichever is the lowest applies.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 10
Practical limits
EN378-1 specifies practical limits for all the refrigerants it covers. Note – some refrigerants
such as the proprietary hydrocarbon blends are not currently included in this standard.
To determine the maximum charge imposed by the practical limit (PL), the room volume is
multiplied by PL.
Examples of maximum charge determined by PL
Cold room size 4 m by 5 m by 2.5 m high, cooled by a direct expansion system using R290.
Cold room volume = 8 m x 5 m x 2.5 m = 100 m3.
R290 PL = 0.008 kg/m3.
Max charge = 100 x 0.008 kg = 0.8 kg.
As above but using R1234yf.
Cold room volume = 8 m x 5 m x 2.5 m = 100 m3.
R1234yf PL = 0.06 kg/m3.
Max charge = 100 x 0.06 kg = 6 kg.
Preparation room 3 m by 4.5 m by 2.8 m high, in which a direct expansion ice maker using
R1270 is located.
Preparation room volume = 3 m x 4.5 m x 2.8 m = 37.8 m3.
R1270 PL = 0.008 kg/m3.
Max charge = 37.8 x 0.008 kg = 0.302 kg.
The practical limit can be exceeded in machine rooms, but if this is the case the design of the
machine room must comply with EN378 and it will be designated a special machine room
(see sub section at the end of this section).
In addition to the limits above, EN378 also specifies overall maximum charges – whichever is
lowest applies. The section below shows these.
Overall maximum charge sizes
The tables below summarise the most common scenarios for A2 and A3 refrigerants. Refer
to EN378-1 for other scenarios and full information.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 11
Direct expansion systems
Area being cooled 1 System location
All areas
General occupancy
- class A
General occupancy
- class A
Supervised
occupancy – class B
Supervised
occupancy – class B
Authorised access –
class C
Authorised access –
class C
Part or all of system below
ground
Whole of system at
ground level or above
Whole of system at
ground level or above and
in an unoccupied machine
room or open air
Whole of system at
ground level or above and
in human occupied area
Whole of system at
ground level or above;
compressor and receiver
in open air or machine
room
Whole of system at
ground level or above and
in human occupied area
Whole of system at
ground level or above;
compressor and receiver
in open air or machine
room
Max change, A2
refrigerants
As below
Max charge, A3
refrigerants
1 kg
38 x LFL
1.5 kg
132 x LFL
5 kg
10 kg
2.5 kg
25 kg
2.5 kg
10 kg, or
25 kg if < 1
person per 10
m2, and there
are sufficient
emergency exits
25 kg, or
No restriction if
< 1 person per
10 m2
10 kg
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
25 kg
Page | 12
Indirect systems
Area being cooled 1
All areas
General occupancy
- class A
General occupancy
- class A
System location
Part or all of system below
ground
Whole of system at
ground level or above,
compressor and receiver
in open air or machine
room
Whole of system at
ground level or above and
in an unoccupied machine
room or open air
Supervised
occupancy – class B
Whole of system at
ground level or above,
compressor and receiver
in open air or machine
room
Supervised
occupancy – class B
Whole of system at
ground level or above and
in an unoccupied machine
room or open air
Authorised access –
class C
Whole of system at
ground level or above,
compressor and receiver
in open air or machine
room
Whole of system at
ground level or above and
in an unoccupied machine
room or open air
Authorised access –
class C
Max change, A2
refrigerants
As below
Max charge, A3
refrigerants
1 kg
Apply comfort
cooling / heating
practical limit
1.5 kg
No restriction if
exit to open air
and no direct
communication
with A and B
areas
No restriction if
machine room
has no direct
communication
to occupied
space
No restriction if
machine room
has no direct
communication
to occupied
space
No restriction
5 kg
No restriction
No restriction
2.5 kg
10 kg
25 kg
1. Area being cooled, see table below for full explanation and examples. If there is
more than one category of occupancy the more stringent applies. If occupancies
are isolated from each other the requirements of the individual category applies.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 13
Class Location where …
Examples
A
Hospitals and nursing homes
Prisons
Theatres, lecture halls
Supermarkets, restaurants, hotels
Transport termini
Ice rinks
Laboratories
Places for general manufacturing
Office buildings
People may sleep;
The number of people present is not
controlled;
Any person has access without being
personally acquainted with the
personal safety precautions
Only a limited number of people may
be assembled, some of them being
necessarily acquainted with the
general safety precautions.
May be a room or part of a building.
Not open to the general public where
only authorised persons are granted
access.
Authorised persons are acquainted
with general safety precautions.
B
C
Cold stores and abattoirs
Refineries
Non public areas in supermarkets
Manufacturing facilities (e.g.
chemicals, food)
Special machine rooms
A special machinery room is a machinery room intended only for the installation of the
complete refrigerating system or components of the refrigerating system. It is accessible
only to competent personnel for the purposes of maintenance and repair. EN378-3:2008
specifies general requirements for machine rooms plus additional requirements for A3
refrigerants. These include specifications for:







Sealing of piping and ducting through walls;
Doors and exits;
Ventilation
Emergency mechanical ventilation;
Explosion relief;
Equipment inside the room;
Alarms and leak detection systems.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 14
5. Systems / Applications
Some system types are ideal for use with flammable refrigerants whereas for others
flammable refrigerants should never be used. The table overleaf is a very simple summary
showing which systems are suitable and which are not. It uses a traffic light system:
Green – these systems are suitable for the refrigerant type indicated, and the charge
size is usually within the limits specified in EN378. Some design changes are
required to electrical devices and / or ventilation (see section 6 for more information
on this).
Amber – these systems can and are used with the refrigerant type indicated, but
there are restrictions because of the maximum charge or practical limit specified in
EN378. Some design changes are required to electrical devices and / or ventilation
(see section 6).
Red – these systems should not be used with the refrigerant type indicated, usually
because the charge size exceeds the maximum specified in EN378-1.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 15
System
HCs
HFOs and flammable
HFCs
Integral systems, < 150 g charge
Integral systems, 150 g to 1.5 kg charge,
e.g. ice makers
Integral supermarket display cabinets and
serve overs, 150 g to 1.5 kg charge, to be
located on a supermarket shop floor
Cold room or beer cellar cooled by a mono
block system
Cold room or beer cellar cooled by a
remote condensing unit
DX process cooling
Split AC systems
Portable AC systems
VRV / VRF systems
Water (and other fluid) chillers
Central plant systems
Existing CFC, HCFC and HFC systems
Note – this table should be used as an indication of the suitability of different systems.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 16
6. Overview of Design
A leak of flammable refrigerant can result in a potentially flammable zone around the
system. Sources of ignition within the potentially flammable zone will present a hazard in
the event of a leak. An essential part of the design process is to identify the extent of the
potentially flammable zone and ensure there are no sources of ignition inside it.
As an example, the process for ensuring HC systems are safe is summarised below for any
system which contains sources of ignition, regardless of the charge size.
Step 1
Minimise the refrigerant charge size.
Reduce leakage potential.
Step 2
Carry out simulated leak testing (area classification) to determine the extent of
the potentially flammable zone in the event of a leak. Note – this must be
carried out by a suitably qualified competent person in a controlled (safe) area.
A risk assessment must be carried out prior to releasing flammable refrigerant.
This procedure was developed for HCs that can be vented and are not controlled
by legislation such as the Fluorinated Gas (F Gas) Regulation5.
Step 3
Identify sources of ignition within the potentially flammable zone.
Option 1 - move the source of ignition outside the potentially flammable zone.
Option 2 - replace the source of ignition with a suitable device.
Step 4
Option 3 - increase the air flow and / or maintain a permanent air flow to
reduce the potentially flammable zone.
Option 4 - locate the source of ignition in a suitable enclosure (this is usually
cost prohibitive for small systems and difficult to achieve).
Step 5
5
Label the system with the ISO flammable gas label, information about the safe
working procedures and minimum room sizes if appropriate. An example label
is given in Appendix 1.
EC Regulation No 842/2006 on certain fluorinated greenhouse gases
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 17
More detailed information about the design of HC systems is provided in the BRA Code
of Practice for the Design and Manufacture of Refrigerated Cabinets Running on
Hydrocarbon Refrigerants. Much of this information is also relevant to larger systems and
for A2 refrigerants.
The approach for area classification for A2 and A2L (proposed) refrigerants has not yet been
determined. It requires some consideration in view of the potential release of refrigerants
controlled by the Fluorinated Gas Regulation.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 18
7. Overview of Manufacture
Systems should be assembled and processed in accordance with EN378 and following good
refrigeration practice. There are issues related specifically to the use of flammable
refrigerants which must be addressed:
Accuracy of charge for critically charged systems. Because of the lower charge weight of
HCs and flammable HFCs compared to non-flammable HFCs, the tolerance can be less than
±5g in small systems.
Location. The charging area must not be below ground level. There must be no below
ground areas adjacent to the charging areas where leaking refrigerant could collect.
Ventilation. Usually two levels of ventilation are used which extract air at low level from
the charging area and discharge it to an area outside. Fan motors should be rated for use in
a potentially flammable atmosphere.
Sources of ignition. An area around the charging equipment should be free from sources of
ignition.
Flammable gas detection. The type used should accurately sense the refrigerant being
used, and not be affected by other airborne substances. Sufficient sensors should be used
to ensure a leak of flammable refrigerant is detected. In this event the control system
should switch on the high level ventilation and activate an alarm.
Storage of flammable refrigerant. The minimum quantity of flammable refrigerant should
be inside the charging area. All other cylinders should be stored outside in a safe area.
Operator training. Operators charging flammable refrigerant and their supervisors should
be trained in the safe handling of these refrigerants. See section 9 for more information.
Access. Access to the charging area should be restricted to personnel who have received
safe handling training.
Flammable refrigerant supply. Any pipe work associated with flammable refrigerant
charging should be protected from accidental damage.
Fire extinguishers. Fire extinguishers should be located in the charging area (dry powder or
CO2 types).
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 19
8. Overview of Service
Systems should be serviced and maintained following good refrigeration practice, with some
changes to tools, equipment and procedures. Engineers working on flammable gas system
should be appropriately trained, see Section 9.
Tools and equipment
Tools should be rated for use in a Zone 2 area or have been suitably tested for use with
flammable refrigerants. Type ‘n’ protection according to EN60079-15 is deemed as suitable
for this application. Note – this is not intrinsic safety.



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A flammable gas detector should be used to monitor the air in the work area.
The photo shows a detector suitable for HC refrigerants.
If an electronic leak detector is used it must be safe and sensitive to the
flammable refrigerant. Most HFC leak detectors do not need this
requirement. Leak detection fluid can be used.
HFC recovery machines have not been assessed for use with flammable
refrigerants. Approval must be sought from the manufacturer before using a
standard HFC recovery machine with any flammable refrigerant – they may be
safe to use with flammable HFCs but not HCs. A recovery machine suitable
for use with HCs is available and could be used with other flammable
refrigerants.
More accurate scales are necessary when charging small, critical charged systems with
some flammable refrigerants such as HCs. An accuracy of ±5 g is often necessary – most
scales used for service are not this accurate.
A dry powder or CO2 fire extinguisher must be available at the location.
A suitable ventilation fan should be used when working inside if there is insufficient
natural ventilation.
Procedures
The work area must be well ventilated with no source of ignition within 3 m of the system
and the service equipment such as a vacuum pump and recovery machine. Note – 3 m is the
typical zone required for HC refrigerants. For A2 and A2L (proposed) refrigerants, and
where there is good ventilation, the zone may be less.
The vacuum pump should be controlled by a switch outside the 3m zone (the vacuum
pump’s switch should not be used as it is a source of ignition) and the pump should be
located in a well-ventilated area.
Prior to un brazing joints the flammable refrigerant must be removed from the system, and
the system filled with nitrogen.
Faulty electrical devices and compressors must be replaced with like for like components.
Procedures for working with A2 and A2L (proposed) refrigerants have not yet been
formulated, so the procedures for A3 refrigerants (HCs) should be followed until these are
available.
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 20
9. Training
EN378-4 specifies that anyone working on flammable refrigerants systems should receive
training which includes the following:

Knowledge of legislation, regulation and standards relating to flammable
refrigerants;

Detailed knowledge of and skill in handling flammable refrigerants, personal
protective equipment, refrigerant leakage prevention, handling of cylinders,
charging, leak detection, recovery and disposal.
Training on the design of flammable refrigerant systems and training for technicians who will
be handling these refrigerants in manufacture and service has been available in the UK since
the mid 1990s.
In early 2012 City and Guilds launched an HC
pathway unit as part of the new City & Guilds
61876 - C & G 6187-21 Understand and apply
hydrocarbon RAC system installation, testing,
servicing and maintenance techniques. The
Unit includes both a theory and a practical
assessment. The photo shows the equipment
used in the practical assessment. Candidates do
not need to do the other parts of the C & G 6187
qualification as this unit is a stand-alone
qualification (successful candidates will receive a
City & Guilds certificate).
Anyone handling the HFOs and flammable HFCs must have an F Gas qualification such as City
and Guilds 2079 or the Construction Skills J11.
6
Certificate and Diploma in Refrigeration Air-conditioning and Heat Pump Systems
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 21
10. Sources of Further Information
This table below provides details of organisations and publications for more information
about various aspects of HC refrigerants.
Item
Website
Companies who provide products and services
related to HC refrigerants
www.hydrocarbons21.com
British Refrigeration Association
www.feta.co.uk
Institute of Refrigeration Safety Code of Practice for
systems utilising A2 and A3 refrigerants
www.ior.org.uk
Ammonia Refrigeration Systems Code of Practice
www.ior.org.uk
Standards referenced in this Code
www.bsigroup.co.uk
City and Guilds
www.cityandguilds.com
HFO1234yf in the automotive industry
www.sae.org
American Society of Heating, Refrigeration and Air
Conditioning Engineers
Business Link – various information relating to
transportation of systems charged with flammable
refrigerant
International Air Transport Association (IATA) for the
transport of systems charged with flammable
refrigerant by air
Civil Aviation Authority for information on the
carriage of systems charged with flammable
refrigerant by air
International Maritime Organisation for information
about the carriage of systems charged with
flammable refrigerant by rail
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
www.ashrae.org
www.businesslink.gov.uk
www.iata.org
www.caa.co.uk
www.imo.org
Page | 22
Appendix 1, Example Label for a Flammable Refrigerant System
Refrigerant R290 (Propane)
This unit must not be located in a room or area with a volume less than XXX m3.
Note: Only engineers who have been trained in the safe handling and use of hydrocarbon
(HC) refrigerants should work on this system.
 Work on this system in a well-ventilated area or
outside.
 Use a local leak detector to indicate if there is
hydrocarbon in the air around the system before and
during work on the system (place it at low level - HCs
are heavier than air).
 Ensure there are no sources of ignition (flames or
sparking electrical components) within 3 m (10 feet)
of your work area.
 If replacing components, use like for like
replacements.
 Take great care when brazing to ensure all HC has been removed from the system.
Use refrigerant grade propane (R290).
BRA Guide to Flammable Refrigerants, Issue 1, October 2012
Page | 23
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