CIEE Environmental Factors & Human Performance 4

Question 1

A production line worker develops tingling and numbness in fingers after 3 months on a vibrating conveyor. ISO 5349 daily vibration exposure A(8) is 4 m/s². What stage of Hand-Arm Vibration Syndrome (HAVS) does this suggest?

Accepted Answer

Stockholm Workshop Scale Stage 1 (vascular) — intermittent tingling with or without numbness

Answer

Early neurological symptoms (tingling, occasional numbness) with no blanching correspond to Stage 1SN on the Stockholm Scale, consistent with early HAVS from moderate vibration exposure.

Question 2

Which parameter determines the Recommended Exposure Limit (REL) for chemical mixtures in relation to ergonomic heat stress assessments?

Accepted Answer

Metabolic heat production increases absorption rate of skin-permeable chemicals

Answer

Elevated metabolic rate during heat stress increases cardiac output and pulmonary ventilation, which can increase inhalation dose rates for airborne chemicals, potentially making standard RELs insufficient.

Question 3

What is the primary limitation of using A-weighted decibel measurements (dBA) for assessing low-frequency noise in ergonomic evaluations?

Accepted Answer

A-weighting heavily attenuates frequencies below 250 Hz, underestimating low-frequency noise impacts on annoyance and cognitive performance

Answer

The A-weighting filter was designed to model hearing damage risk, but significantly de-emphasizes low-frequency content that contributes to annoyance, vibrotactile effects, and cognitive distraction.

Question 4

An ergonomist recommends task rotation to reduce cumulative heat stress. Which physiological principle supports this intervention?

Accepted Answer

Allowing partial core temperature recovery between exposures limits cumulative heat storage

Answer

Core temperature rises during hot work; rotation to a cooler task or rest allows partial dissipation of stored heat, preventing progressive thermal accumulation toward dangerous levels.

Question 5

A warehouse uses high-intensity discharge (HID) lamps with a 15-minute warm-up period. Workers must perform visual inspection immediately after a power outage. What is the primary ergonomic hazard?

Accepted Answer

Sudden transition from emergency lighting to complete darkness before HID lamps restrike, causing dark adaptation loss and accident risk

Answer

HID lamps require up to 15 minutes to restart after power loss; workers transitioning between lighting levels in this period face severely impaired visibility and dark adaptation that increases accident risk.

(CIEE) Certified Industrial Ergonomic Evaluator Practice Test

(CIEE) Certified Industrial Ergonomic Evaluator Practice Test

CIEE Environmental Factors & Human Performance 4