Occupational Health and Safety, and Environmental Protection
The Occupational Health and Safety, and Environmental Protection domain tests whether you can work on refrigeration and air conditioning equipment without injuring yourself, the building occupants, or the atmosphere. Expect items on hazard identification, PPE, energy isolation, refrigerant safety classification, pressure-system and electrical safety, and the Canadian rules that govern refrigerant handling and release.
Energy and atmosphere hazards
- Control of hazardous energy follows CSA Z460: isolate, lock, tag, and verify. Refrigeration equipment stores energy in pressure, springs, capacitors, flywheels and hot oil, so a locked disconnect alone is not verification.
- Refrigerant vapour displaces air. Oxygen deficiency below 19.5% is immediately dangerous; a large leak in a machine room means ventilate from outside and enter only with supplied air.
- Liquid refrigerant at atmospheric pressure boils near -40°C; contact causes instant frostbite. Wear a face shield and cryogenic gloves, never a rag over a fitting.
Classification and limits
ASHRAE 34 / ISO 817 classes: A1 (R-134a, R-410A) shows no flame propagation and lower toxicity; A2L (R-32, R-454B) is lower flammability; B1 (R-123) is higher toxicity; B2L (ammonia, R-717) is toxic and flammable. Compliance is judged against the refrigerant concentration limit (RCL) for A1 and A2L refrigerants, not the older oxygen deprivation limit.
Environmental rules
Canada's Federal Halocarbon Regulations, 2022 and provincial ODS/halocarbon regulations require certified technicians, leak detection and repair, recovery before a circuit is opened, and record keeping. HFCs are managed under the Kigali Amendment phase-down, which is why R-410A is being replaced by A2L blends.
Worked example
A 30 m³ room holds a 10 kg R-32 charge. 10 ÷ 30 = 0.33 kg/m³. The RCL for R-32 is about 0.32 kg/m³, so the charge exceeds the limit: the code then requires a refrigerant detector with alarm and mitigation, or a reduced charge. With 8 kg the concentration is 0.27 kg/m³ and the room passes.
Traps
- Quoting ODL instead of RCL for an A2L refrigerant.
- Assuming "A2L" means non-flammable.
- Venting a blend because it is "not ozone depleting" - release is still prohibited.
- Recording a recovered weight without subtracting the cylinder tare.