Noise Exposure and Hearing Conservation Programs Flashcards

In a free field, doubling the distance from a point noise source reduces the sound pressure level by approximately how much?

Answer: 6 dB

The inverse square law gives about a 6 dB drop per doubling of distance from a point source.

Noise-induced hearing loss typically first appears as a 'notch' on the audiogram at which frequency?

Answer: 4000 Hz

Noise damage characteristically produces a dip near 4000 Hz with recovery at 8000 Hz.

Which weighting network and meter response does OSHA specify for measuring noise for compliance?

Answer: A-weighting, slow response

OSHA noise levels are measured on the A-weighted scale at slow response.

Which chemical exposure is recognized as ototoxic and may worsen hearing loss when combined with noise?

Answer: Toluene

Solvents such as toluene, styrene, and xylene are ototoxic and act synergistically with noise.

NIOSH's recommended exposure limit for noise differs from OSHA's PEL in that it uses which criteria?

Answer: 85 dBA with a 3 dB exchange rate

NIOSH recommends 85 dBA as an 8-hour TWA with a more protective 3 dB exchange rate.

Which is an example of an engineering control for noise on a construction site?

Answer: Installing a muffler or acoustic enclosure on a generator

Mufflers and enclosures reduce noise at the source or path, which is an engineering control.

A temporary threshold shift (TTS) after a noisy shift is best described as which of the following?

Answer: A short-term hearing reduction that usually recovers with rest, but warns of overexposure

TTS is a reversible hearing decrease that signals overexposure and can lead to permanent loss if repeated.