Practice Test Geeks(HERS) Certified Home Energy Rating System Rater Practice Test
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Combustion Safety Principles Flashcards

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

Read the first 7 Combustion Safety Principles flashcards as text

  1. When sizing combustion air openings for appliances in a confined space, the upper opening should be located:

    Answer: Within 12 inches of the ceiling to exhaust heat

    The upper combustion air opening is placed within 12 inches of the ceiling per code, allowing hot flue gases to escape and drawing fresh air in through the lower opening.

  2. A HERS rater finds that a home's new airtight construction has pushed the CAZ pressure to -7 Pa during worst-case conditions. The best long-term remediation is:

    Answer: Replace naturally vented appliances with sealed-combustion or direct-vent equipment

    Replacing atmospherically vented appliances with sealed-combustion or direct-vent models eliminates dependence on indoor air pressure for safe venting.

  3. What OSHA permissible exposure limit (PEL) for CO over an 8-hour workday should inform a HERS rater's concern about ambient indoor CO levels?

    Answer: 50 ppm

    OSHA's 8-hour TWA PEL for CO is 50 ppm; sustained indoor concentrations approaching this level represent a serious occupational and residential health hazard.

  4. Which condition describes 'flame rollout' in a gas furnace?

    Answer: The burner flame extending out of the combustion chamber into the surrounding area

    Flame rollout occurs when combustion gases cannot exit through a blocked heat exchanger, causing flames to spill out of the burner compartment—a serious fire and CO hazard.

  5. A cracked heat exchanger in a forced-air furnace is a combustion safety concern primarily because:

    Answer: It allows flue gases including CO to mix with circulated supply air

    Cracks in the heat exchanger allow combustion byproducts, including CO, to enter the air distribution system and be circulated throughout the home.

  6. In the context of combustion safety, what does the term 'spillage' refer to?

    Answer: Combustion gases escaping from the draft hood or flue connector into the living space

    Spillage means combustion products are escaping from the venting system at the draft hood or flue connector rather than traveling up and out through the chimney.

  7. Which diagnostic step should be performed BEFORE conducting a worst-case depressurization test on combustion appliances?

    Answer: Record baseline CAZ pressure with house in natural (as-found) conditions

    Recording the baseline (as-found) CAZ pressure before inducing worst-case conditions establishes a reference point and documents pre-existing depressurization issues.