Practice Test Geeks(A2L) A2L Low GWP Flammable Refrigerant Safety Certification Practice Test
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Properties and Classification Flashcards

6 cards from real A2L practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. What is the Global Warming Potential (GWP) of R-32 on a 100-year time horizon, and how does this compare to the HFC phase-down requirements under the AIM Act?

    Answer: GWP of 675 — below the AIM Act's effective thresholds for many equipment categories by 2025-2026

    R-32's 100-year GWP is 675, which is significantly lower than R-410A (GWP 2,088). The AIM Act's HFC phasedown reduces the production and consumption of HFCs to 15% of baseline by 2036, with sector-specific GWP limits set by EPA rulemaking. R-32's GWP of 675 meets the initial AIM Act requirements for many HVAC applications.

  2. What does the 'zeotropic' property of a refrigerant blend like R-454B mean for leak behavior?

    Answer: The blend components evaporate at different rates, so a vapor leak has a different composition than the liquid charge

    Zeotropic blends have components that evaporate and condense at different rates, causing 'fractionation' — a leak releases vapor with a different composition than the original liquid mixture. For R-454B (R-32/R-1234yf), vapor leaks are richer in the more volatile component (R-32), which could affect both performance and flammability characteristics of the remaining charge.

  3. Which A2L refrigerant is classified as a single-component (pure) HFO refrigerant rather than a blend?

    Answer: R-1234yf

    R-1234yf (2,3,3,3-tetrafluoropropene) is a single-component HFO (hydrofluoroolefin) refrigerant with an extremely low GWP of 4. It is used as the primary refrigerant in mobile air conditioning systems in passenger vehicles and is also a component in A2L blends like R-454B and R-452B.

  4. What is the ASHRAE safety group classification for R-410A, and how does it differ from R-454B's classification?

    Answer: R-410A is A1 (non-flammable, lower toxicity); R-454B is A2L (mildly flammable, lower toxicity)

    R-410A is classified A1 by ASHRAE 34 — non-flammable (Class 1) and lower toxicity (Class A). R-454B is classified A2L — mildly flammable with burning velocity ≤10 cm/s (Class 2L) and lower toxicity (Class A). This classification difference has major implications for equipment design requirements, installation rules, and technician safety protocols.

  5. Which industry standard governs the certification of HVAC equipment using A2L refrigerants to ensure safe ignition source control?

    Answer: UL 60335-2-40 (Safety of Household and Similar Electrical Appliances — Heat Pumps, Air Conditioners and Dehumidifiers)

    UL 60335-2-40 is the primary equipment certification standard for HVAC appliances using A2L refrigerants. It specifies requirements for eliminating ignition sources, charge limit compliance, and protective controls. Equipment must be certified to UL 60335-2-40 before it can be installed in the US with A2L refrigerants.

  6. What does 'GWP' stand for and how is it calculated for a refrigerant?

    Answer: Global Warming Potential — the ratio of heat trapped by a gas relative to CO₂ over a specified time horizon (typically 100 years)

    GWP (Global Warming Potential) measures how much heat a greenhouse gas traps relative to the same mass of CO₂ over a specified time period. A 100-year GWP of 675 for R-32 means 1 kg of R-32 traps 675 times as much heat as 1 kg of CO₂ over 100 years. CO₂ itself has a GWP of 1 by definition.