Hydrocarbons & Type I safety: EPA 608 Practice Questions

Isobutane (R-600a), common in new household refrigerators, has which safety class?

R-600a is a hydrocarbon with lower toxicity and higher flammability, classified A3.

How are the service ports and tubing on a refrigerator that uses a hydrocarbon refrigerant marked?

EPA's SNAP use conditions require red marking on service ports and process tubes, plus flammable-refrigerant warning labels, so technicians know to take precautions.

What is the safest way to open the sealed system of an R-290 appliance after the refrigerant has been removed?

A tube cutter avoids an ignition source. Purge the system with nitrogen before any brazing, since oil can still release flammable gas.

Which work-area precaution is most important when servicing an R-600a refrigerator?

Hydrocarbon vapor is heavier than air and can collect in low spots. Ventilate and keep flames, sparks and switches away.

EPA's SNAP rules limit the charge of propane (R-290) in a household refrigerator circuit to about how much?

Household refrigerators and freezers using hydrocarbons are limited to small charges per circuit (150 g under current listings), which keeps any leak below dangerous amounts.

A customer asks to convert an R-134a refrigerator to R-600a to save energy. What is the correct answer?

Under SNAP, hydrocarbon refrigerants are acceptable only in new equipment designed and listed for them. Retrofitting an existing appliance to a flammable refrigerant is not allowed.

Why are relays, switches and some motors a hazard when servicing an R-290 appliance?

Any spark source can ignite a flammable mixture. Unplug the appliance, use non-sparking tools and keep electrical devices away from a possible leak.

Before brazing a new filter-drier into an R-600a refrigerator, what must be done after the refrigerant is removed?

Refrigerant dissolved in the oil can still form a flammable mixture. A nitrogen purge clears it before a flame is used.

What does R-134a form when exposed to an open flame?

Fluorinated refrigerants decompose in a flame into hydrogen fluoride and other toxic, corrosive products. Ventilate before brazing near refrigerant.

Which protective equipment should a technician wear when recovering refrigerant from a small appliance?

Escaping liquid refrigerant can freeze skin and injure eyes, so glasses and gloves are needed even on small appliances.

Why is releasing R-600a inside a closed shop dangerous, even though it is exempt from the venting ban in household refrigerators?

Isobutane is heavier than air and flammable. In a closed space it can reach a flammable concentration near the floor, where a spark could ignite it.

What type of leak detector should be used on an R-290 or R-600a appliance?

The detector must sense hydrocarbons and be safe to use around them. A halide torch uses a flame and detects only chlorine.

Propane (R-290) is an exempt substitute in which of these end uses?

R-290 is exempt in listed self-contained uses, including household refrigerators, stand-alone retail units, vending machines, room AC units, ice machines and water coolers.

When recovering R-600a from a refrigerator, where should the recovery machine be placed?

Use recovery equipment designed for flammable refrigerants and keep it in a ventilated area away from pilot lights and other ignition sources.