RSES Safety Practices & Regulatory Compliance 4 — Questions and Answers
Question 1: What does the DOT classification 'UN 1018' identify?
- Chlorodifluoromethane (R-22) (Correct answer)
- Difluoroethane (R-152a)
- Refrigerant blends (all)
- Ammonia (R-717)
Correct answer: Chlorodifluoromethane (R-22)
UN 1018 is the DOT identification number for chlorodifluoromethane, commonly known as R-22, a refrigerant regulated under both DOT and EPA rules.
Question 2: A refrigeration system using R-717 (ammonia) requires special consideration because ammonia is classified as:
- A1 — low toxicity, non-flammable
- B2L — higher toxicity, lower flammability (Correct answer)
- A3 — low toxicity, high flammability
- B1 — higher toxicity, non-flammable
Correct answer: B2L — higher toxicity, lower flammability
Ammonia (R-717) is classified B2L under ASHRAE 34, indicating higher toxicity (B) and lower flammability with a low burning velocity (2L).
Question 3: Which federal agency regulates the transportation of refrigerant cylinders on public roads?
- EPA
- OSHA
- DOT (PHMSA) (Correct answer)
- NIOSH
Correct answer: DOT (PHMSA)
The Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) regulates the transportation of refrigerant cylinders as hazardous materials.
Question 4: What action must be taken when a refrigerant cylinder's hydrostatic test date has expired?
- Continue using it with a written waiver
- Remove it from service immediately and send for retesting or disposal (Correct answer)
- Mark it clearly and use for recovery only
- Refill it only with non-pressurized refrigerants
Correct answer: Remove it from service immediately and send for retesting or disposal
DOT requires cylinders to be retested at specified intervals; an expired cylinder must be removed from service until retested, or it must be disposed of properly.
Question 5: What is the primary purpose of the EPA's Significant New Alternatives Policy (SNAP) program?
- To certify refrigeration technicians for new refrigerants
- To evaluate and regulate substitutes for ozone-depleting substances (Correct answer)
- To set energy efficiency standards for refrigeration equipment
- To approve new refrigerant blending facilities
Correct answer: To evaluate and regulate substitutes for ozone-depleting substances
The SNAP program evaluates and lists acceptable and unacceptable substitutes for ozone-depleting substances to protect human health and the environment.
Question 6: When brazing refrigerant lines, what gas should be flowed through the tubing to prevent oxidation scale formation inside the lines?
- Carbon dioxide (CO2)
- Oxygen (O2)
- Dry nitrogen (N2) (Correct answer)
- Compressed air
Correct answer: Dry nitrogen (N2)
Dry nitrogen is purged through tubing during brazing to displace oxygen and prevent copper oxide scale from forming, which would contaminate the refrigerant system.
Question 7: Which of the following refrigerants is classified as a lower-flammability (A2L) refrigerant that requires special handling precautions compared to A1 refrigerants?
- R-22
- R-410A
- R-32 (Correct answer)
- R-134a
Correct answer: R-32
R-32 (difluoromethane) is classified A2L — mildly flammable with low burning velocity — requiring ignition source management that is unnecessary for A1 refrigerants like R-410A.
RSES Safety Practices & Regulatory Compliance 4
What does the DOT classification 'UN 1018' identify?