Jobsite and Occupational Safety
Hazard categories to know
HVAC work combines electrical, refrigerant, combustion, pressure, chemical, and fall hazards. The exam expects you to recognize hazard classes and the administrative control that answers each: lockout/tagout for electrical and rotating equipment, personal protective equipment for eyes, hands, and hearing, confined space procedures for crawl spaces and vaults, and fall protection for elevated work. Use the standard rule that fall protection is required at roughly six feet in construction, and that ladders are set at a four-to-one slope and secured.
Refrigerants and pressure
Refrigerant displaces oxygen in low, enclosed spaces and can cause asphyxiation; liquid refrigerant causes frostbite and cold burns. Never heat a cylinder with an open flame or exceed its rated temperature, never fill a recovery cylinder beyond 80 percent by volume, and always secure cylinders upright. Use a nitrogen regulator, never a direct high-pressure connection, and never use oxygen as a pressure test gas.
Hot work and electrical
Brazing requires a fire watch, a rated extinguisher, shielding from combustibles, and awareness that attic and crawl space work concentrates both heat and flammable materials. Treat all circuits as energized until verified and locked out; verify with a meter rated for the available fault current, and wear arc-rated protection when required.
Heat and general safety
Arizona heat illness is a genuine jobsite hazard: water, rest, shade, acclimatization, and buddy checks are the controls. Housekeeping, proper ladder use, tool guarding, and safe lifting prevent the routine injuries that cost the most in claims.
Worked example
Before brazing in an attic, remove or shield combustibles, wet down nearby wood if permitted, set the extinguisher within reach, confirm nitrogen flow and ventilation, and keep a second person aware of your location.