CAOHC Noise Measurement and Control 3

Question 1

What does a noise dose of 200% indicate about a worker exposure?

Accepted Answer

The worker received twice the maximum allowable daily noise exposure

Answer

A noise dose of 200% means the worker was exposed to twice the permissible noise dose, equivalent to approximately 95 dBA TWA.

Question 2

What is the purpose of noise contour mapping in a workplace?

Accepted Answer

To create a visual representation of noise levels across the facility for identifying high-exposure areas

Answer

Noise contour maps show spatial distribution of noise levels, helping identify areas where workers need protection.

Question 3

Which engineering control technique reduces noise by preventing vibration transmission between machinery and structures?

Accepted Answer

Vibration isolation using resilient mounts or pads

Answer

Vibration isolation mounts prevent mechanical vibrations from machinery from being transmitted to structures that can radiate noise.

Question 4

What is the threshold level setting on a noise dosimeter and why is it important?

Accepted Answer

The minimum sound level below which the dosimeter does not accumulate dose, set at 80 dBA for OSHA

Answer

The threshold is the minimum level the dosimeter includes in its dose integration. OSHA specifies 80 dBA for hearing conservation measurements.

Question 5

How does doubling the distance from a point noise source affect the sound level in a free field?

Accepted Answer

Sound level decreases by approximately 6 dB

Answer

In a free field, doubling the distance from a point source results in a 6 dB reduction in sound pressure level per the inverse square law.

CAOHC - Council for Accreditation in Occupational Hearing Conservation Practice Test