EPA EPA Refrigerant Types and Properties 2 — Questions and Answers
Question 1: What is the primary environmental concern with CFC refrigerants such as R-11 and R-12?
- High flammability risk
- Ozone layer depletion (Correct answer)
- High toxicity to humans
- Groundwater contamination
Correct answer: Ozone layer depletion
CFC refrigerants release chlorine atoms when broken down by UV radiation in the stratosphere, which catalytically destroy ozone molecules.
Question 2: Which refrigerant has an ASHRAE safety classification of A2L, indicating it is mildly flammable?
- R-134a
- R-410A
- R-32 (Correct answer)
- R-22
Correct answer: R-32
R-32 is classified as A2L because it is mildly flammable with a low burning velocity, requiring specific handling precautions compared to non-flammable refrigerants.
Question 3: What is the critical temperature of a refrigerant?
- The temperature at which the refrigerant becomes toxic
- The lowest temperature at which refrigerant can exist as a liquid
- The temperature above which the refrigerant cannot be liquefied regardless of pressure (Correct answer)
- The boiling point of the refrigerant at atmospheric pressure
Correct answer: The temperature above which the refrigerant cannot be liquefied regardless of pressure
The critical temperature is the point above which a substance cannot exist in liquid form no matter how much pressure is applied.
Question 4: How are refrigerant blends with a temperature glide best charged into a system?
- As a vapor through the high side
- As a liquid from the cylinder (Correct answer)
- As a vapor through the low side
- Mixed with oil before charging
Correct answer: As a liquid from the cylinder
Zeotropic refrigerant blends with temperature glide should be charged as a liquid to maintain the correct mixture ratios and prevent fractionation.
Question 5: Which refrigerant was commonly used in automotive air conditioning before being phased out due to ozone depletion concerns?
- R-134a
- R-12 (Correct answer)
- R-410A
- R-404A
Correct answer: R-12
R-12 (dichlorodifluoromethane) was the standard automotive AC refrigerant until it was phased out under the Clean Air Act due to its high ODP.
Question 6: What does 'ODP' stand for in refrigerant classification?
- Optimal Discharge Pressure
- Ozone Depletion Potential (Correct answer)
- Operating Dew Point
- Outdoor Design Parameter
Correct answer: Ozone Depletion Potential
ODP (Ozone Depletion Potential) measures how much a refrigerant can destroy stratospheric ozone relative to R-11, which has an ODP of 1.0.
EPA EPA Refrigerant Types and Properties 2
What is the primary environmental concern with CFC refrigerants such as R-11 and R-12?