Health Risks
- Asphyxiation: most refrigerant vapours are heavier than air and push out oxygen in basements, pits and plant rooms.
- Heart effects: high concentrations can cause irregular heartbeat (cardiac sensitisation).
- Frostbite: liquid refrigerant flashes at very low temperatures and can freeze skin and eyes.
- Decomposition: flames or hot surfaces can break refrigerants down into toxic acids. Ventilate the area, and never braze on a system that is still charged.
Personal Protective Equipment
Wear safety glasses or goggles and insulated gloves when handling refrigerant. In a large spill in an enclosed space, a self-contained breathing apparatus (SCBA) may be needed. Under ASHRAE Standard 15, equipment rooms need a refrigerant detector or oxygen-deprivation sensor that sounds an alarm and starts ventilation.
Cylinders
- Fill refillable recovery cylinders to no more than 80% liquid volume, so there is room for liquid expansion.
- Recovery cylinders have a gray body and yellow top. They must be DOT-approved and within their retest date.
- Never refill disposable cylinders. Empty them to 0 psig, make them unusable and recycle them.
- Store cylinders upright, secured, and away from heat above 125 °F.
- Shipped cylinders of used refrigerant need the right refrigerant label and DOT hazard classification tag.
Pressure Testing
Use dry nitrogen with a pressure regulator and a relief valve. Never use oxygen, which can explode when mixed with oil, or compressed air. Don't exceed the system's rated test pressure.
Flammable Refrigerants (A2L and A3)
R-32, R-454B and R-1234yf (A2L) and propane or isobutane (A3) can ignite. Use recovery equipment rated for flammable refrigerants, remove ignition sources and follow the maker's procedures. The guide to refrigerant types, classes and A2L safety explains the classes.
Why Safety Is Tested in Every Section
EPA's test topics include safety in the Core section and in each technical type, because the hazards change with the equipment. A household fridge holds a few ounces of refrigerant, a rooftop unit holds pounds, and a chiller can hold hundreds of pounds in a closed plant room. The same basic rules apply to all of them, but the consequences of a mistake grow with the charge size and the space.
Working in Enclosed Spaces
Most refrigerant vapours are heavier than air and have little or no smell at concentrations that are already dangerous. A large leak in a basement, pit or equipment room can displace enough oxygen to cause dizziness, unconsciousness or death without warning. Before you enter a space where a large leak is possible:
- Check whether the room has a working refrigerant detector or oxygen sensor, and whether it is alarming.
- Ventilate the space. Mechanical ventilation that draws air from low points is most effective because vapour collects near the floor.
- Never work alone in a confined space with a known large leak.
- If someone collapses, do not rush in without breathing protection. Call for help and ventilate first.
Handling Liquid Refrigerant
Liquid refrigerant boils at very low temperatures at atmospheric pressure. When it escapes from a hose or fitting, it can freeze skin and eyes almost instantly. Keep these habits:
- Wear safety glasses or goggles and gloves whenever you connect or disconnect hoses.
- Use hoses with low-loss fittings or shut-off valves to reduce the amount of refrigerant released.
- Point fittings away from your face when you loosen them.
- If liquid contacts skin or eyes, follow the safety data sheet and get medical attention for any frostbite.
Heat, Flames and Decomposition
When refrigerant meets an open flame or a very hot surface, it can decompose into toxic and corrosive products. That is why refrigerant must be recovered before brazing and why the area should be ventilated. A sharp, acrid smell during brazing can mean refrigerant is still present. Stop work and ventilate.
Cylinder Transport
Cylinders in vehicles should be secured upright so they can't roll or fall, with valve caps in place. Don't leave cylinders in a closed vehicle in hot weather, because the pressure rises with temperature. Keep cylinders away from heat sources and direct flame, and never heat a cylinder with a torch to speed up charging.
Safety Data Sheets
Every refrigerant has a safety data sheet (SDS) from its manufacturer. The SDS lists exposure limits, first aid steps, fire-fighting advice and handling precautions. Know where to find the SDS for each refrigerant you carry.
Exam Tips for Safety Questions
- Choose dry nitrogen for pressure testing. Oxygen and compressed air are always wrong answers.
- The maximum fill for a refillable cylinder is 80% by liquid volume.
- Recovery cylinders are gray with a yellow top.
- The main danger of a large leak in an enclosed space is oxygen displacement.
- Refrigerant exposed to flame can form toxic decomposition products.
Equipment Rooms and ASHRAE 15
ASHRAE Standard 15 sets safety requirements for refrigeration systems and machinery rooms. Key ideas that appear on the exam include refrigerant detectors that sound an alarm and start mechanical ventilation, and the need for self-contained breathing apparatus when responding to large leaks in enclosed spaces. The exact requirements depend on the refrigerant, the charge size and the local code adopted.
Shipping Used Refrigerant
When you ship recovered refrigerant to a reclaimer, the cylinder must meet Department of Transportation rules. Label it with the refrigerant type and its hazard class, and make sure it is within its test date and not overfilled. Many reclaimers and wholesalers supply cylinders and labels and can explain their requirements.
A Short Safety Checklist
- Glasses and gloves on before connecting hoses.
- Ventilation checked in enclosed spaces.
- Correct recovery cylinder, labelled and under 80% full.
- Nitrogen with regulator and relief valve for testing.
- Refrigerant recovered before brazing.
Key Terms
- Asphyxiation: loss of consciousness or death from lack of oxygen.
- Cardiac sensitisation: irregular heartbeat caused by high refrigerant concentrations.
- SCBA: self-contained breathing apparatus, needed for large leaks in enclosed spaces.
- Relief valve: a device that opens to release pressure before a cylinder or system ruptures.
- DOT: the U.S. Department of Transportation, which sets cylinder and shipping rules.
- SDS: safety data sheet, the maker's document on hazards and handling.
Common Exam Traps
- Picking compressed air for leak testing. It's never correct.
- Forgetting that disposable cylinders must never be refilled.
- Thinking refrigerant vapour rises. Most refrigerant vapours are heavier than air.
- Assuming A1 refrigerants are completely safe. They can still displace oxygen and decompose in flames.
Building Safe Habits
Most refrigerant injuries come from routine tasks done in a hurry, such as disconnecting a hose without glasses or brazing before recovery is complete. Make the safety steps part of your normal routine so they happen even on busy days.
Quick Questions
Can I store a recovery cylinder in my van overnight?
Secure it upright with its cap on and avoid hot conditions. Pressure rises with temperature, so don't leave cylinders in a closed vehicle in hot weather.
Is it safe to braze near a system with refrigerant in it?
No. Recover the refrigerant first and ventilate. Refrigerant exposed to flame can decompose into toxic and corrosive products.
What should I do after a large leak in a plant room?
Leave the area, alert others and ventilate. Only trained responders with SCBA should enter until the oxygen level is safe.
Do A2L refrigerants need special cylinders?
Flammable refrigerants are supplied in cylinders marked for them, and many use left-hand threaded valves to prevent mix-ups. Use recovery cylinders and machines rated for the refrigerant.
What PPE is the minimum for routine service?
Safety glasses or goggles and gloves suitable for cold liquid refrigerant. Add more protection where the job or the SDS calls for it.
Test your safety knowledge with the EPA 608 Core practice test.