Responsible Refrigeration
limit ( RCL ); this is the refrigerant concentration limit , in air , determined and intended to reduce the risks of acute toxicity , asphyxiation , flammability and fire hazards in normally occupied , enclosed spaces .
The auto-ignition temperature is the lowest temperature at which a refrigerant will spontaneously ignite in a normal atmosphere without an external source of ignition flame or spark . This is the biggest danger . Since a flame can be propagated in the range between the LFL-UFL , a practitioner should avoid the concentration of refrigerant in the working area reaching the LFL and the temperature of refrigerant from reaching the auto-ignition temperature .
Full safety checks must be carried out and procedures be followed at all times and for all refrigerants , even when they are classified as lower toxicity or non-flammable . To prevent fire hazards when using flammable refrigerants , relevant standards have been adopted to limit the charge size of flammable refrigerant in refrigeration and air conditioning units .
The fire triangle is composed of the three components that produce a physicochemical reaction to ignite a fire : heat , fuel , and oxygen . A fire can occur naturally when these three elements occur simultaneously in the appropriate proportions .
This is what happens when a practitioner does not follow procedures and precautions when working with flammable refrigerants .
In principle , the following factors must be considered to determine charge limits of flammable refrigerants in a RAC system . Flammability group of the refrigerant , for example , R-290 and R600a are group A3 ( flammable ) while R-32 is group A2L ( lower flammability ). The A designated lower toxicity . Occupancy classification and location classification of refrigeration and air conditioning equipment must also be considered . RACA
" The auto-ignition temperature is the lowest temperature at which a refrigerant will spontaneously ignite "
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RACA Journal I October 2021 www . hvacronline . co . za