Which statement best describes hazardous noise exposure?

Which statement best describes hazardous noise exposure?

• A. Environments with continuous noise levels below 60 dB are hazardous
• B. Environments or equipment that produce continuous noise levels at or above 85 dB(A) TWA and impact noises exceeding 140 dB(A) are hazardous
• C. Hazardous noise only at 200 dB
• D. Hazardous noise is any level above 90 dB

Answer: (B)

Hazardous noise exposure depends on both how loud the sound is and how long you’re exposed to it, including how impulsive (short, sharp) noises behave. We use A-weighted decibels to reflect what the human ear is most sensitive to, and a time-weighted average to account for duration. The best statement matches standard limits: continuous noise at or above 85 dB(A) over an 8-hour workday is considered hazardous, and impulsive or impact noises that exceed 140 dB(A) can also cause damage. This covers the two main risk types you encounter in maintenance: long-term exposure to loud but steady noise, and sudden loud peaks that can injure hearing even if the average over time isn’t extremely high. Why the other ideas aren’t right: hazards aren’t tied to very low levels like below 60 dB, since those are generally safe. A value like 200 dB(A) isn’t realistic in typical environments and isn’t how hazard thresholds are defined. And saying any level above 90 dB is hazardous ignores how exposure duration and impulse peaks affect risk; a single number without considering time and peak information doesn’t accurately describe hazard. So the statement that combines both a continuous 85 dB(A) TWA threshold and a 140 dB(A) peak impulse threshold best reflects how hazardous noise exposure is evaluated.

Hazardous noise exposure depends on both how loud the sound is and how long you’re exposed to it, including how impulsive (short, sharp) noises behave. We use A-weighted decibels to reflect what the human ear is most sensitive to, and a time-weighted average to account for duration.

The best statement matches standard limits: continuous noise at or above 85 dB(A) over an 8-hour workday is considered hazardous, and impulsive or impact noises that exceed 140 dB(A) can also cause damage. This covers the two main risk types you encounter in maintenance: long-term exposure to loud but steady noise, and sudden loud peaks that can injure hearing even if the average over time isn’t extremely high.

Why the other ideas aren’t right: hazards aren’t tied to very low levels like below 60 dB, since those are generally safe. A value like 200 dB(A) isn’t realistic in typical environments and isn’t how hazard thresholds are defined. And saying any level above 90 dB is hazardous ignores how exposure duration and impulse peaks affect risk; a single number without considering time and peak information doesn’t accurately describe hazard.

So the statement that combines both a continuous 85 dB(A) TWA threshold and a 140 dB(A) peak impulse threshold best reflects how hazardous noise exposure is evaluated.