Responsible Refrigeration
BARNEY RICHARDSON
By Barney Richardson
Barney Richardson is the director of South African Refrigeration and Air Conditioning Contractors Association ( SARACCA ) and sits on various other boards within the HVAC industry , including the South African Qualifications and Certifications Committee for Gas ( SAQCC ) Gas .
WORKING WITH REFRIGERANTS
AND THEIR FLAMMABILITY
Last month we talked about the flammable refrigerants like R290 and R600a which are classified as group A3 . R-32 is classified as group A2L , only with lower flammability .
The ‘ A ’ designates a refrigerant with a lower toxicity at an occupational exposure limit ( OEL ) of 400 ppm or greater . The ‘ B ’ designation is the higher toxicity where refrigerants have an occupational exposure limit of less than 400 ppm .
The F-gas refrigerants we have all been used to for air conditioning and refrigeration such as R22 , R134a , R404 and R410a are all classed as A1 low toxicity and flammability . But why can ’ t we use them anymore ? It ’ s all about global warming and ozone depletion , therefore the move to natural refrigerants .
For interest Ammonia ( R717 ) is classified as B2L which has a flammability under certain conditions and is toxic but warns you of its presence by the smell . Ammonia , a great refrigerant , has been used for many years and will continue to be used in low charge systems .
There are many skilled specialist practitioners working on Ammonia systems . New to us in supermarkets is Carbon Dioxide
( R744 ) which is classed as A1 with only low toxicity and the potential to displace Oxygen in confined places . CO 2 also requires specialist skills and experience .
Table 1 : Classification of refrigerant safety groups ( ASHRAE Standard 34-2019 ).
High Flammability A3 B3 Flammable A2 B2 Low Flammability A2L B2L No Flame propagation A1 B1
Low Toxicity
High Toxicity
There is now the introduction of flammable refrigerants in domestic refrigerators and beverage coolers into South Africa which places a greater responsibility for skills on the R290 and R600a refrigerants . There is also R32 – soon to be introduced in room air conditioners .
While attending to repairs and maintenance , there is the risk of a flammable refrigerant being released during recovery or charging . The risk of an ignition is always there - for example any electrical sources . Certainly smoking or allow anyone to smoke near your work area must be strictly avoided . This leakage is certainly possible when connecting and / or disconnecting gauge hoses for recovery or charging .
It would be wise to have at least a 2-metre temporary flammable work zone in all directions of an outdoor condensing unit , or if indoors , from the refrigeration appliance . For larger refrigeration systems using a flammable refrigerant the safe distance allowed should be even greater . If the area is a confined space , for example within a house or building , this must be well ventilated . Practitioners should always consider the work area of
www . hvacronline . co . za RACA Journal I November 2021 43