Refrigerant Safety
Protect yourself from oxygen displacement, frostbite, high pressure and toxic decomposition gases when you work near refrigerant.
Table of contents
Most refrigerants are not poisonous in small amounts, and that can lead to carelessness. They can still suffocate you, freeze your skin, send a fitting flying, or turn into toxic gas near a flame. Each of those hazards has a simple rule that prevents it.
What You Will Be Able to Do
- Explain why a refrigerant leak in a closed space can kill.
- Choose the right protection for handling refrigerant.
- Keep refrigerant away from flames and hot surfaces.
- Respond correctly to a large leak or a skin exposure.
Oxygen Displacement
Most refrigerants are heavier than air. A large release in a basement, pit, walk-in box or mechanical room sinks to the low spots and pushes out breathable air. You cannot see this happening, and many refrigerants have little or no smell. A person may feel dizzy and then pass out with very little warning. That is called asphyxiation.
Warning: Never enter a room or low space where you suspect a large refrigerant release until it has been ventilated and tested. Do not go in after a coworker who has collapsed. Call for trained rescue.
Prevention:
- Ventilate before you start work in a small or enclosed space.
- If a machine room has a refrigerant alarm, respect it and leave when it sounds. ASHRAE 15 calls for refrigerant sensors and ventilation in many machine rooms.
- Keep your head out of pits and low spots if you suspect a leak.
Frostbite
Liquid refrigerant boils at very low temperatures. R-410A boils at about -60°F at atmospheric pressure. If it touches your skin or eyes, it boils off instantly and freezes tissue. This can happen when a hose comes off or a fitting lets go.
- Wear safety glasses or goggles every time you connect or disconnect a hose. Add a face shield when you handle cylinders or large transfers.
- Wear gloves made for the job, such as butyl or another insulated type rated for refrigerant contact, when liquid contact is possible.
- Point hose ends and fittings away from your face.
- Stand to the side when you crack a fitting.
If liquid hits your skin, get away from the source and warm the area gently with lukewarm water. Do not rub it. If liquid hits your eyes, flush them with water and get medical help right away.
Pressure
Refrigerant systems run at high pressure, and modern systems run higher than older ones. R-410A can exceed 500 psig on a hot day with a dirty condenser. Carbon dioxide systems can run above 1,400 psig.
- Use gauges, hoses and tools rated above the pressures you expect. For R-410A class systems that means at least 800 psig on the high side and 500 psig on the low side.
- Replace hoses that are cracked, bulged or chewed at the ends.
- Open valves slowly.
- Never heat a cylinder with a torch or flame. Pressure rises fast as a cylinder warms. Warm water is the most you should use, and keep it below 125°F.
- Never fill a recovery cylinder past 80% of its capacity by weight, because liquid expands as it warms.
Use a regulator with nitrogen. A nitrogen cylinder can hold over 2,000 psi, which will burst a refrigeration circuit. Never use oxygen or compressed air to pressurize refrigerant lines. Oxygen mixed with oil can explode, and compressed air adds moisture.
Decomposition Near Heat
When refrigerant passes through a flame or touches a very hot surface, it breaks down into toxic and corrosive gases. Refrigerants with chlorine, such as R-22, can form phosgene and hydrochloric acid. Fluorinated refrigerants such as R-410A can form hydrofluoric acid and carbonyl fluoride. A sharp, acrid smell near a torch, a gas flame or an electric heater means you should stop and get to fresh air.
Warning: Never braze or torch a line that still holds refrigerant. Recover the refrigerant first, then purge with nitrogen.
Flammability
Some refrigerants burn. A3 refrigerants such as propane burn easily, and A2L refrigerants such as R-32 and R-454B burn under the right conditions. Check the data plate before you bring a torch, a heat gun or a non-rated tool near a system.
Toxicity
Most refrigerants in comfort cooling are in the lower-toxicity A group. Ammonia (R-717) is a B-group refrigerant. It is a strong irritant, and the OSHA permissible exposure limit is 50 ppm averaged over 8 hours. Ammonia systems need specific training and procedures. R-123 in large chillers has a low exposure limit, which is why its machine rooms have refrigerant sensors. Always read the Safety Data Sheet for the refrigerant you are handling.
Stale Oil and Burned Systems
When a compressor burns out, its oil can turn acidic. Avoid contact with the oil and fumes. Wear gloves and eye protection, and ventilate the area when you open the system.
Who May Handle Refrigerant
Safety and the law point the same way here. Federal rules under EPA Section 608 require certification for work that could release refrigerant from stationary equipment. Residential air conditioners and heat pumps are high-pressure equipment, which falls under Type II. Knowingly venting refrigerant is illegal, and penalties can pass $100,000 per day for each violation. If you are not certified, do this work only under the close supervision of a certified technician.
What to Do in a Large Leak
- Leave the area and warn others.
- Keep people out until the space has been ventilated.
- If the refrigerant is A2L or A3, or if ammonia is involved, treat it as a fire or toxic hazard and call emergency services if needed.
- Shut down the equipment from a safe place if you can do that without entering the area.
- Tell your supervisor. Refrigerant loss may need to be recorded or reported.
Common Mistakes
| Mistake | What it costs |
|---|---|
| Skipping glasses for a quick gauge check | A blown hose can freeze an eye |
| Working in a small space with no ventilation | Dizziness, collapse |
| Cutting a line that was not recovered | Refrigerant spray and a violation |
| Warming a cylinder with a torch | The cylinder can rupture |
| Using an old R-22 gauge set on R-410A | Gauges and hoses fail under pressure |
Check Your Understanding
You smell something sharp while brazing on a line you were told was empty. What should you do? Stop, shut off the torch, leave for fresh air and ventilate. The refrigerant may be breaking down in the flame.
Why is a refrigerant leak more dangerous in a basement than on a rooftop? Refrigerant is heavier than air. It collects in low, closed spaces and pushes out oxygen.
A coworker gets liquid refrigerant on a bare hand. What is the first aid? Move away from the source and warm the skin gently with lukewarm water. Do not rub it. Get medical help for serious injury.
Your hoses are rated for 500 psig on the high side. Should you use them on an R-410A system? No. Use a set rated for at least 800 psig on the high side.
Key Takeaways
- Most refrigerants are heavier than air and can displace oxygen in closed spaces.
- Liquid refrigerant causes frostbite, so eye and hand protection comes first.
- Use tools rated for the pressure, and never heat a cylinder with a flame.
- Refrigerant near flame forms toxic gases, so recover and purge before hot work.
- Use only dry nitrogen with a regulator for pressure work.