CPE CPE Environmental Ergonomics Questions and Answers 1 — Questions and Answers
Question 1: OSHA's permissible exposure limit (PEL) for occupational noise is 90 dBA as an 8-hour TWA with what exchange rate?
- 3 dB doubling rate
- 5 dB doubling rate (Correct answer)
- 6 dB doubling rate
- 10 dB doubling rate
Correct answer: 5 dB doubling rate
OSHA's PEL uses a 5 dB exchange rate (time-intensity trade-off), allowing 95 dBA for 4 hours or 100 dBA for 2 hours as exposure doubles.
Question 2: Wet Bulb Globe Temperature (WBGT) is used to assess heat stress and accounts for which environmental factors?
- Air temperature only
- Air temperature, humidity, radiant heat, and air movement (Correct answer)
- Wind chill and barometric pressure
- Humidity and altitude
Correct answer: Air temperature, humidity, radiant heat, and air movement
WBGT combines natural wet bulb (humidity/evaporation), black globe (radiant heat), and dry bulb (air temperature) measurements to characterize total thermal stress.
Question 3: Which type of lighting is most recommended for detailed visual inspection tasks in industrial settings?
- Ambient (general) lighting only
- High-intensity task lighting supplemented by appropriate ambient lighting (Correct answer)
- Colored fluorescent lighting
- Strobe lighting for motion detection
Correct answer: High-intensity task lighting supplemented by appropriate ambient lighting
Detailed inspection tasks require high-intensity task lighting targeted at the work surface, supplemented by adequate ambient lighting to minimize contrast discomfort.
Question 4: What is the recommended ASHRAE thermal comfort temperature range for sedentary office work in summer?
- 60–65°F (15–18°C)
- 68–70°F (20–21°C)
- 73–79°F (23–26°C) (Correct answer)
- 80–85°F (27–29°C)
Correct answer: 73–79°F (23–26°C)
ASHRAE Standard 55 recommends an operative temperature range of approximately 73–79°F (23–26°C) for sedentary office occupants in summer conditions.
Question 5: Noise-Induced Hearing Loss (NIHL) first affects which frequency range?
- 250–500 Hz
- 1,000–2,000 Hz
- 4,000 Hz (4 kHz notch) (Correct answer)
- 8,000–10,000 Hz
Correct answer: 4,000 Hz (4 kHz notch)
NIHL characteristically presents first as a 'notch' at 4,000 Hz on the audiogram before spreading to adjacent frequencies with continued exposure.
Question 6: Glare in visual ergonomics is classified as either disability glare or discomfort glare. Which type directly reduces visual acuity?
- Discomfort glare
- Disability glare (Correct answer)
- Reflected glare
- Specular glare
Correct answer: Disability glare
Disability glare directly impairs visual acuity by scattering light across the retina, reducing contrast and the ability to distinguish details.
CPE CPE Environmental Ergonomics Questions and Answers 1
OSHA's permissible exposure limit (PEL) for occupational noise is 90 dBA as an 8-hour TWA with what exchange rate?