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Indoor Environmental Quality and Safety Flashcards

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

Read the first 7 Indoor Environmental Quality and Safety flashcards as text

  1. An indoor CO2 reading about 700 ppm above the outdoor level roughly corresponds to what outdoor air rate per sedentary occupant?

    Answer: 15 cfm per person

    At steady state, a CO2 differential of about 700 ppm indicates roughly 15 cfm of outdoor air per sedentary person.

  2. Which ASHRAE standard defines conditions for human thermal comfort in occupied spaces?

    Answer: ASHRAE Standard 55

    ASHRAE 55 specifies the combinations of temperature, humidity, air speed, and other factors that produce acceptable thermal comfort.

  3. What indoor relative humidity range is generally recommended to limit mold growth and dust mites while avoiding overly dry air?

    Answer: 30% to 60%

    Keeping RH between about 30% and 60% limits microbial growth and dust mites without causing dryness complaints.

  4. Which situation is best described as a building-related illness rather than sick building syndrome?

    Answer: An employee is diagnosed with Legionnaires' disease traced to the cooling tower

    Building-related illness has clinically diagnosable symptoms with an identifiable building source, such as Legionella from a cooling tower.

  5. To reduce Legionella growth in domestic hot water systems, at what minimum temperature should water heaters typically store water?

    Answer: 140°F (60°C)

    Storing hot water at 140°F (60°C) or above suppresses Legionella, which grows best between about 77°F and 113°F.

  6. An atmospheric gas water heater in a mechanical room begins spilling flue gases after a large exhaust fan is installed nearby. What is the most likely cause?

    Answer: Negative room pressure reversing the draft

    Exhaust fans that depressurize a space can overcome the natural draft and cause backdrafting of combustion products.

  7. Occupants report a sewer gas odor near a rarely used floor drain. What is the most likely cause and fix?

    Answer: A dry P-trap; refill it with water or install a trap primer

    Water in an unused trap evaporates, letting sewer gas through, so refilling the trap or adding a trap primer restores the seal.

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