CIEE Environmental Factors & Human Performance 3

Question 1

A facility switches from fluorescent to LED lighting and workers report more eyestrain. Which LED characteristic most likely causes this if illuminance levels are equivalent?

Accepted Answer

Higher flicker rate or low modulation depth at certain dimmer settings

Answer

LEDs dimmed with incompatible drivers can produce perceptible flicker at frequencies that cause eyestrain and headaches even when average illuminance seems adequate.

Question 2

OSHA's permissible exposure limit (PEL) for noise is 90 dBA as an 8-hour TWA. Using the 5-dB exchange rate, what is the maximum allowable exposure duration at 95 dBA?

Accepted Answer

4 hours

Answer

With the OSHA 5-dB exchange rate, each 5-dB increase halves the allowable exposure time; 90 dBA = 8 h, so 95 dBA = 4 h.

Question 3

Which environmental condition most significantly degrades manual dexterity and increases error rates in precision assembly tasks?

Accepted Answer

Hand skin temperature below 15°C (59°F)

Answer

Tactile sensitivity and fine motor control decline sharply when hand skin temperature drops below 15°C, directly impairing precision assembly performance.

Question 4

An ergonomist measures CO2 at 1,800 ppm in a conference room where workers report difficulty concentrating. What is the most appropriate corrective action?

Accepted Answer

Increase outdoor air supply rate through HVAC to reduce CO2 below 1,000 ppm

Answer

ASHRAE Standard 62.1 targets CO2 below ~1,000 ppm as a surrogate for adequate outdoor air dilution; increasing fresh air supply is the direct and most effective intervention.

Question 5

Which shift work schedule poses the greatest circadian disruption risk and associated performance decrement?

Accepted Answer

Rapidly rotating shifts with counter-clockwise rotation (night → evening → day)

Answer

Counter-clockwise rapid rotation forces the circadian clock to phase-advance, which is physiologically harder than phase-delay, resulting in greater sleep disruption and performance loss.

(CIEE) Certified Industrial Ergonomic Evaluator Practice Test

(CIEE) Certified Industrial Ergonomic Evaluator Practice Test

CIEE Environmental Factors & Human Performance 3