313A Refrigerants & Environmental Regulations 2 — Questions and Answers
Question 1: What refrigerant classification is R-717 (ammonia)?
- A1 (low toxicity, non-flammable)
- B2L (higher toxicity, lower flammability) (Correct answer)
- A2L (low toxicity, mildly flammable)
- B3 (higher toxicity, higher flammability)
Correct answer: B2L (higher toxicity, lower flammability)
Ammonia (R-717) is classified as B2L under ASHRAE 34 — 'B' for higher toxicity and '2L' for lower flammability (mildly flammable), requiring special safety considerations in system design and operation.
Question 2: What is the primary environmental concern with R-410A that is driving its phase-down under the Kigali Amendment?
- High ozone depletion potential
- Very high global warming potential (GWP ~2088) (Correct answer)
- Extreme flammability risk
- High toxicity to HVAC technicians
Correct answer: Very high global warming potential (GWP ~2088)
R-410A has a GWP of approximately 2088, making it a potent greenhouse gas; the Kigali Amendment to the Montreal Protocol requires the phase-down of high-GWP HFCs including R-410A.
Question 3: What low-GWP refrigerant is being widely adopted as a replacement for R-410A in residential HVAC systems?
- R-32 (Correct answer)
- R-404A
- R-507A
- R-123
Correct answer: R-32
R-32 (difluoromethane) has a GWP of 675 — significantly lower than R-410A — and is being widely adopted as a more climate-friendly replacement for residential air conditioning globally, including in Canada.
Question 4: Under Canadian ODSHAR regulations, what must technicians do with recovered refrigerant that cannot be reused?
- Vent it outdoors in a remote location
- Store it in an approved container and send it to a licensed refrigerant reclaimer or destruction facility (Correct answer)
- Mix it with new refrigerant to dilute contaminants
- Return it to the original equipment manufacturer
Correct answer: Store it in an approved container and send it to a licensed refrigerant reclaimer or destruction facility
Intentional venting of controlled refrigerants is prohibited in Canada; recovered refrigerant that cannot be reused must be sent to a licensed reclaimer or destruction facility in approved containers.
Question 5: What is R-744 and what is its main advantage as a refrigerant?
- It is R-134a with a UV dye tracer; its advantage is leak detection
- It is CO2; its GWP is 1 (the baseline), making it extremely climate-friendly (Correct answer)
- It is R-410A blended with nitrogen; it is non-flammable
- It is propane; it is cheap and widely available
Correct answer: It is CO2; its GWP is 1 (the baseline), making it extremely climate-friendly
R-744 is carbon dioxide (CO2), and because GWP is referenced to CO2, its GWP is exactly 1, making it one of the most climate-friendly refrigerant options available.
Question 6: What does the term 'zeotropic blend' mean for refrigerants such as R-407C?
- A refrigerant blend that behaves as a single pure fluid with no temperature glide
- A blend of refrigerants with different boiling points that exhibit a temperature glide during phase change (Correct answer)
- A refrigerant that cannot be separated into its components
- A natural refrigerant with zero GWP
Correct answer: A blend of refrigerants with different boiling points that exhibit a temperature glide during phase change
Zeotropic blends are mixtures of refrigerants with different boiling points; they exhibit temperature glide — the temperature changes during evaporation and condensation at constant pressure — which must be accounted for in system design.
313A Refrigerants & Environmental Regulations 2
What refrigerant classification is R-717 (ammonia)?