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Many refrigerants used today carry an A1 safety classification. The “A” represents their toxicity rating, based on the level to which an individual can be exposed over his working life without ill effects. Class A refrigerants are identified as having no toxicity at concentrations at or below 400 ppm. The “1” represents their flammability characteristics. Class 1 refrigerants do not show flame propagation when tested in air at 14.7 psia and 65˚F. Not all refrigerants in use today carry an A1 safety classification, so one of the first precautions a technician should take is to identify the refrigerant used in the system and follow the safety guidelines associated with that refrigerant.
Even refrigerants with an A1 safety classification can pose a safety hazard if mishandled or abused. At atmospheric pressure, many refrigerants will evaporate at temperatures below ‑20˚. If liquid refrigerant comes in contact with the skin, it could cause severe frostbite. Always wear safety gloves and glasses when working with refrigerant. Keep all the gaskets used on refrigerant hoses and associated equipment in good working condition. Poorly maintained gaskets can prevent a good seal, leading to liquid refrigerant spraying from a fitting. Liquid refrigerant can also spray out when installing and removing refrigerant hoses from a Schrader valve. To minimize this risk, technicians should use hoses with low loss fittings. Hoses can be purchased with these fittings, or an adapter can be added to an existing hose.
Although most refrigerants are considered nontoxic, if sufficient quantities leak from a system, especially in an enclosed space, you must be careful not to inhale the vapor. Inhalation of refrigerants can cause dizziness, nausea, heart irregularities, unconsciousness, or even death. Even though the vapor itself may be considered nontoxic, it replaces the oxygen that your body needs to survive, and your body will suffer the effects of suffocation.
Refrigerants will decompose when exposed to high temperatures, such as when in the presence of an open flame or electric resistive heaters. As refrigerant decomposes, toxic and irritating byproducts are formed. These include hydrogen chloride for CFC and HCFC refrigerant, and hydrogen fluoride for CFC, HCFC, and HFC refrigerants. These acidic vapors are very hazardous and the area should be evacuated and ventilated to prevent exposure to any personnel. This is one of the many reasons why refrigerant must be removed from a system prior to soldering or brazing any of its refrigerant components.
Another potential hazard from refrigerants is from the cylinders. If a cylinder is overpressurized, it could explode, causing a severe safety hazard. When working with refrigerant cylinders, observe the following precautions:
• Do not store cylinders above temperatures of 130˚.
• Never use a torch to heat a refrigerant cylinder.
• Never use a cylinder that shows signs of rust or corrosion.
• Never use a cylinder that shows a bulge.
• On recovery cylinders, do not fill to more than 80 percent of their capacity.
• Cylinders have relief valves — do not tamper with these valves.
• Have recovery tanks pressure tested every five years.
Working safely is a must for any technician. Keeping focused, alert, and paying attention to details will prevent most unnecessary refrigerant-based injuries.
Publication date: 5/7/2012