Safety: EPA 608 Practice Questions

Why is a large refrigerant leak in a basement or other enclosed space dangerous?

Most refrigerant vapors are heavier than air, collect in low areas and can cause suffocation without warning. Ventilate and leave the area if a large release occurs.

What can happen when refrigerant vapor contacts an open flame or a very hot surface?

Heat decomposes fluorinated refrigerants into acids such as hydrofluoric acid, and chlorinated ones can also form hydrochloric acid and phosgene.

Why must oxygen or compressed air never be used to pressurize a refrigeration system?

Oxygen and oil under pressure can ignite violently. Use dry nitrogen with a regulator for pressure testing.

When pressurizing a system with nitrogen, what equipment must be on the nitrogen cylinder?

A full nitrogen cylinder can hold over 2,000 psig. A regulator sets a safe test pressure and a relief valve protects against over-pressure.

What protective equipment should a technician wear when handling refrigerant cylinders and hoses?

Liquid refrigerant can cause frostbite and blind the eyes, so wear safety glasses and gloves whenever connecting hoses or handling refrigerant.

What is the safe way to warm a refrigerant cylinder to speed up charging?

Never use a flame or direct heat. Warm water or a cylinder heater made for the purpose keeps the cylinder well below 125°F.

In the ASHRAE 34 safety classification, what does the letter "B" in a class such as B1 mean?

The letter shows toxicity: A is lower toxicity and B is higher toxicity. The number shows flammability.

In ASHRAE 34, a refrigerant classified A1 has which properties?

A1 refrigerants such as R-410A and R-134a have lower toxicity and do not propagate a flame under the standard test.

R-123, used in low-pressure chillers, has which ASHRAE 34 safety class?

R-123 is B1: higher toxicity, no flame propagation. That is why equipment rooms with R-123 need refrigerant monitors.

Why is it dangerous to fill a cylinder until it is completely full of liquid?

A liquid-full cylinder has no vapor space. A small temperature rise makes the liquid expand and builds enormous hydrostatic pressure that can burst it.