The BRA has released its Guide to Flammable Refrigerants – author and IOR past president Jane Gartshore takes a looks at the highlights
The British Refrigeration Association commissioned the Guide to Flammable Refrigerants in response to the increased availability of this diverse range of refrigerants. It is fair to paraphrase George Orwell: “All these refrigerants are flammable, but some are more flammable than others.”
The Guide is aimed at end-users, specifiers, building owners, manufacturers and contractors, and provides an introduction to flammable refrigerants. It contains impartial information about the flammability issues and would enable a specifier, for example, to make an informed decision when selecting a refrigerant.
The Guide covers the following refrigerants (ammonia (R717 is not included in the Guide):
· HCs: hydrocarbons – naturally occurring substances containing only hydrogen and carbon;
· HFCs: hydrofluorocarbons – halocarbon containing only hydrogen, fluorine and carbon;
· HFOs: hydrofluoroolefin – halocarbon containing only hydrogen, fluorine and unsaturated carbon;
The Guide applies to the use of flammable refrigerants in new, specially designed systems. It does not recommend the retrofit of existing systems using non-flammable refrigerants to flammable refrigerants.
Regulations and standards that cover the use of flammable refrigerants are fully listed in the Guide.
The flammability of the refrigerants included in the Guide varies – they have different lower flammability levels (LFLs) and ignition temperatures. Some are highly flammable such as the HCs, and others are barely flammable, such as the HFOs.
The table above outlines the most common flammable refrigerants (others are included in the Guide so refer to that for full information).
Application of flammable refrigerants
Some types are ideal for use with flammable refrigerants, whereas others definitely are not.
The table on the right is reproduced from the Guide as a simple summary showing which systems are suitable using the 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 (refer to the Guide 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 (refer to the Guide).
· Red – these systems should not be used with the refrigerant type indicated, usually because the charge size exceeds the maximum specified in EN378-1.
The Guide is available from the British Refrigeration Association: www.feta.co.uk/associations/bra. The BRA also has a Code of Practice on the design and manufacture of refrigerated cabinets running on hydrocarbon refrigerants. Both documents were written by Cool Concerns Ltd, which can also provide more detail about the safe use of these refrigerants – see www.coolconcerns.co.uk for more information.