Support
GRANT LAIDLAW
Grant Laidlaw is currently the owner of the Air Conditioning and Refrigeration Academy ( ACRA ) in Edenvale . He holds a Bachelor of Business Administration and an associate degree in educational administration . He has a National Technical Diploma and completed an apprenticeship with Transnet . He has dual-trades status : refrigeration and electrical . He has been involved with SAIRAC for 17 years and has been a Johannesburg committee member for the past eight ( chairman in 2011 and 2012 ). Currently he is the treasurer ( Johannesburg council ) as well as president ( national council ).
SAFE WORKING PRACTICES AND R32
By Grant Laidlaw
Dealing with refrigerants of any kind holds a legal requirement that such persons be authorised to do so .
Johann asks : Grant , there is talk on hydrocarbon refrigerants , the flammability aspect and required training , but what of R32 ? Surely some training is required as at the end of the day R32 does fall into the A2L category . Can you give some indication as to safe working practice for R32 .
Hi Johann , yes you are absolutely correct . It does seem that R32 units are being supplied to installers who do not have the necessary knowledge to deal with the flammable refrigerants . Having said that , it is a legal requirement under the OHS act ( Pressure Vessel Regulation ) that any person working with refrigerants needs to be an authorised person . As an authorised person , he / she will have received training and will have been assessed as competent for working with refrigerants including the hydro carbons and R32 refrigerants .
R32 is included in the safe handling of refrigerants course offered nationally under the South African Refrigeration and Air Conditioning Contractors Associations control ( SARACCA ).
Looking into some of the safe working practices for R32 refrigerant , the following can be used as a guide .
GOOD PRACTICE IN THIS REGARD SHOULD BE :
• That compliance with regulations shall be observed .
• The length of pipe-work shall be kept to a minimum .
• You should protect the pipe work from damage that may cause a leak .
• Servicing shall only be performed as recommended by the equipment manufacturer .
• Maintenance and repair shall be carried out by or under the supervision of the person competent in the use of flammable refrigerants .
• Servicing shall be performed as per manufacturer ’ s specifications .
• Maintenance staff and others working in the local area shall be informed on the nature of work being carried out .
• Working in confined spaces should be avoided .
• The area around the workspace should be cordoned off .
• Remove flammable materials from the work area .
• Ensure that the leak detection equipment being used is suitable for use with flammable refrigerants .
• Appropriate fire extinguishing equipment shall be available at hand . Have a dry powder or CO₂ fire extinguisher adjacent to the charging area .
For any work that needs to be conducted on a system that utilises a flammable refrigerant we need to implement some safety measures and safety checks in order to reduce the risk of ignition .
The charge size is relative to the room size within which the refrigerant unit is installed . To put this simply , should a catastrophic leak occur into the refrigerated space , the concentration of the refrigerant when mixed with air shall be below the lower flammability limit , which for R32 is 14 %. It is interesting to note that ; International Standard ISO 817:2014 , segregates the flammability of refrigerants into 4 categories as follows : no flame propagation ( Class 1 ), lower flammability ( Class 2L ), flammable ( Class 2 ) and higher flammability ( Class 3 ).
In general language these classifications are called Non- Flammable , Mildly Flammable , Flammable and Highly Flammable . R32 falls into the ‘ lower flammability ’ or Class 2L ‘ mildly flammable ’ category .
Any refrigerant and air mixture that is capable of selfpropagating a flame falls into one of the three flammable categories . Class 2L refrigerants present the lowest risk of the flammable categories and are defined by having a burning velocity of less than 10cm per second . The characteristic of this low burning velocity is that the flame front does not propagate readily in a horizontal direction .
Continued on page 39
www . hvacronline . co . za RACA Journal I April 2021 37