Safety Practices and Code Compliance
Personal safety, refrigerant law, and code
The license carries legal and safety obligations. Personal protection first: eye protection and gloves, arc-rated clothing where required, lockout and tagout before electrical work, and awareness that liquid refrigerant causes frostbite and vapor displaces oxygen and decomposes into toxic products near flame. Follow ladder, fall protection, and confined space rules. Never pressure-test with oxygen; use dry nitrogen.
Refrigerant law: EPA Section 608 certification is required for handling regulated refrigerants, knowing venting is prohibited, recovery and recycling equipment must be used, cylinders have fill limits, and refrigerants are classified by safety group under ASHRAE 15 and 34. A2L refrigerants such as R-32 and R-454B bring charge limits, refrigerant detection, and ventilation requirements; they are not drop-in replacements.
Code compliance covers permits and inspections, combustion air and venting (Category I through IV appliances, correct vent connector slope), clearance to combustibles, condensate disposal, seismic restraint, fire and smoke damper installation, and California Title 24 energy requirements.
Traps: undersized combustion air openings; condensate lines terminated where they can freeze or cause a hazard; a vent connector installed with negative slope; jumping out a limit or pressure switch to make a unit run.
Worked example: a 100,000 Btu/h natural-draft appliance in a confined space typically uses two permanent openings, each sized near 1 in. squared per 1,000 Btu/h of input, split high and low, adjusted for louver free area. Confirm against the adopted code before installing.