Flash fires and refrigerant system servicing

Following a number of serious incidents which have resulted in workers being severely burnt when a mixture of refrigerant and compressor oil was expelled and ignited while servicing air-conditioning refrigerant systems, SafeWork NSW has released a Safety Alert.

Using oxy-acetylene torches to unsweat copper fittings can expose workers to the risk of flash fire if residual pressure in the system causes R22 refrigerant and oil to be released from the pipe joint and act as an ignition source.

The Safety Alert recommends:

Review your current procedures and ensure safe working practices include:

• reclaiming the refrigerant before breaking into the system;
• ensuring the work area is well ventilated;
• using pipe cutters or similar to cut the pipe.

The use of an oxy-acetylene torch or similar to unsweat pipe joints should only be carried out as a last resort and under very strict and controlled conditions.

If an oxy-acetylene torch or similar is used, it is recommended that:

• the relevant requirements of the Welding processes code of practice and AS 1674.1 Safety in welding and allied processes are complied with;
• the system is purged with dry nitrogen following full recovery of the refrigerant;
• adequate ventilation is provided to remove hazardous gases;
• appropriate personal protective equipment and fire protection equipment is used.