Refrigerants, Safety, and Environmental Regulations
This section covers refrigerants, safety, and environmental rules: refrigerant identification, recovery, evacuation, leak repair, safe handling, and the extra requirements for flammable or lower-GWP refrigerants. The exam expects compliance with federal Section 608 rules and correct field practice.
Handling and records
Do not vent refrigerant. Recover into a DOT-approved recovery cylinder, never fill above the cylinder's marked limit, and evacuate to the required micron level before charging. Keep recovery equipment and hoses in good condition; use PPE for frostbite and liquid contact. Section 608 certification is required for technicians who service, maintain, repair, or dispose of appliances above the regulatory charge threshold. Record charge amounts, leak repairs, and recovery.
Safety groups and A2L
ASHRAE 34 classifies refrigerants by toxicity and flammability. A1 refrigerants are lower toxicity and no flame propagation; A2L refrigerants are lower flammability. A2L systems require ignition-source control, ventilation, charge-limit checks, and components listed for the refrigerant. Do not substitute refrigerants or mix oils without manufacturer approval.
Worked example
A commercial refrigeration appliance has a 50 lb charge and loses 6 lb over 12 months. The annual leak rate is 6 / 50 = 12%. For a commercial refrigeration appliance subject to the 20% federal leak-repair threshold, the rate is below the trigger, but venting is still prohibited. If the same loss occurred on a comfort-cooling appliance with a 10% threshold, it would exceed the threshold and require repair and verification. Always compare with the appliance category and current rule.
Traps
Topping off a leaking system without repair; confusing leak-rate thresholds; using a recovery cylinder as a storage tank; ignoring A2L charge limits; and failing to purge hoses safely.