CES Environmental Ergonomics

Question 1

According to OSHA's permissible exposure limit (PEL), what is the maximum noise exposure allowed for an 8-hour workday without hearing protection?

Accepted Answer

90 dBA

Answer

OSHA's PEL for noise is 90 dBA as an 8-hour time-weighted average (TWA); exposure above this requires engineering controls or hearing protection.

Question 2

What is the recommended illuminance level (in foot-candles) for general office tasks such as reading and writing according to the Illuminating Engineering Society (IES)?

Accepted Answer

30–50 fc

Answer

IES recommends 30–50 foot-candles (300–500 lux) for general office work such as reading printed materials.

Question 3

Which type of glare occurs when a bright light source is directly within the visual field, causing discomfort or loss of visibility?

Accepted Answer

Discomfort glare

Answer

Discomfort glare causes visual discomfort from a bright source within the field of view, while disability glare actually reduces visual performance.

Question 4

The Wet Bulb Globe Temperature (WBGT) index is used by ergonomists primarily to assess which environmental stressor?

Accepted Answer

Heat stress

Answer

WBGT integrates air temperature, humidity, radiant heat, and air movement to provide a composite index for evaluating heat stress risk.

Question 5

According to ASHRAE Standard 55, the recommended operative temperature range for sedentary office work in summer conditions is approximately:

Accepted Answer

70–76°F (21–24°C)

Answer

ASHRAE 55 specifies approximately 70–76°F (21–24°C) for sedentary work in summer, accounting for lighter clothing insulation.

CES - Certified Ergonomic Specialist Practice Test

CES - Certified Ergonomic Specialist Practice Test

CES Environmental Ergonomics