CFC Alternative Refrigerants & Transitions 5 — Questions and Answers
Question 1: Which EPA program requires that refrigerants used as substitutes for ozone-depleting substances be reviewed for safety and environmental acceptability?
- Clean Air Act Section 608
- SNAP (Significant New Alternatives Policy) Program (Correct answer)
- AIM Act Section 103
- NESHAP Program
Correct answer: SNAP (Significant New Alternatives Policy) Program
The EPA SNAP program, established under Clean Air Act Section 612, evaluates and lists acceptable and unacceptable substitute refrigerants for various end-uses.
Question 2: What is the GWP of R-410A, the most commonly used refrigerant in residential air conditioning before the current transition period?
- 675
- 1430
- 2088 (Correct answer)
- 3922
Correct answer: 2088
R-410A has a GWP of 2088 (100-year), which is why regulators have targeted it for phase-down under the AIM Act and Kigali Amendment.
Question 3: When transitioning from R-12 to R-134a in an automotive AC system, which component typically requires replacement due to incompatibility?
- The evaporator coil
- The condenser fan motor
- The accumulator/drier and hoses (barrier hoses required) (Correct answer)
- The compressor clutch
Correct answer: The accumulator/drier and hoses (barrier hoses required)
R-134a has smaller molecules than R-12 and permeates standard hoses, requiring barrier hoses; the accumulator/drier must also be replaced to ensure compatibility with POE oil.
Question 4: Which of the following best describes an azeotropic refrigerant blend?
- A blend that exhibits significant temperature glide during phase change
- A blend that behaves like a single-component refrigerant with no temperature glide (Correct answer)
- A blend of HFCs and HCFCs
- A blend requiring separate recovery cylinders for each component
Correct answer: A blend that behaves like a single-component refrigerant with no temperature glide
Azeotropic blends behave like pure substances, maintaining a constant composition during phase change and exhibiting negligible temperature glide.
Question 5: Under EPA regulations, what must a technician do if they discover a leak in a commercial refrigeration system containing 50 or more pounds of refrigerant that has exceeded the leak rate threshold?
- Immediately evacuate the building
- Repair the leak within 30 days or retrofit/retire the equipment within 120 days (Correct answer)
- Report the leak to the EPA within 24 hours
- Replace all refrigerant with a natural refrigerant immediately
Correct answer: Repair the leak within 30 days or retrofit/retire the equipment within 120 days
EPA Section 608 regulations require that leaks in systems with 50+ pounds of refrigerant exceeding threshold rates be repaired within 30 days, with retrofit/retirement within 120 days if repair is not feasible.
Question 6: What is the main reason HFO refrigerants like R-1234ze(E) are being considered for low-GWP chiller applications?
- They have the same operating pressures as R-134a
- They have a GWP below 10 and acceptable efficiency in centrifugal chiller applications (Correct answer)
- They eliminate the need for lubricating oil
- They have a higher volumetric capacity than R-134a
Correct answer: They have a GWP below 10 and acceptable efficiency in centrifugal chiller applications
R-1234ze(E) has a GWP of 7 and thermodynamic properties suitable for large centrifugal chillers, making it a viable low-GWP drop-in for R-134a in those applications.
Question 7: Which organization publishes ASHRAE Standard 34, which establishes the naming designation and safety classification system for refrigerants?
- EPA
- ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) (Correct answer)
- UL (Underwriters Laboratories)
- ACCA (Air Conditioning Contractors of America)
Correct answer: ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers)
ASHRAE Standard 34 is published by ASHRAE and is the industry-standard document that assigns refrigerant number designations and A1/A2/A3/B1/B2/B3 safety classifications.
CFC Alternative Refrigerants & Transitions 5
Which EPA program requires that refrigerants used as substitutes for ozone-depleting substances be reviewed for safety and environmental acceptability?