Safety and Environmental Protection
What the exam expects
Safety questions test judgment as much as facts. You must know PPE selection (safety glasses, gloves, respirator), lockout/tagout of electrical and stored energy, arc-flash boundaries, and the physical hazards of refrigerants: frostbite from liquid contact, oxygen displacement in low-lying spaces, and decomposition products when refrigerant meets an open flame.
Environmental content centers on the Section 608 rules that govern your daily work: no knowing venting of refrigerant, recovery before opening a circuit, evacuation levels that vary by appliance size and refrigerant type, and proper documentation. Know that CFCs and HCFCs carry the heaviest restrictions, that HFCs are also regulated, and that refrigerant blends must be charged as liquid to avoid fractionation.
Traps
- Cylinders are stamped with a water capacity; the maximum liquid fill is 80% of that value, not 80% of the refrigerant charge you removed.
- Never use oxygen or acetylene to pressure-test or purge a system. Use dry nitrogen with a regulator.
- Recovery cylinders are not interchangeable for different refrigerants, and an overfilled cylinder can hydrostatically rupture as it warms.
- Carbon monoxide is odorless; a clean flame does not prove a safe heat exchanger.
- "Reclaim" and "recycle" are not the same process.
Worked example
A recovery cylinder is stamped WC 47.6 lb. Maximum refrigerant it may hold is 0.80 x 47.6 = about 38 lb of liquid. If a technician recovers 41 lb into it, the cylinder is overfilled even though it still feels light - stop and move the charge to a second cylinder.