DECIBEL METER SCALE HOW TO

Noise exposure initially affects hearing most at frequencies around 3000-6000 Hz, creating a “notch” in the audiogram. Thresholds which are 25 dB HL (hearing level) or better (lower) are considered normal for adults. If you can’t determine the noise levels safely or accurately, consult the equipment vendor or a noise control engineer.Īudiometry is a hearing test that measures the lowest level of sound a person can hear (called thresholds) across a range of frequencies (pitches).Īn audiogram is a graph of hearing thresholds at various frequencies in each ear. This can help determine which equipment to replace or where to implement noise controls. Record the noise level in each area on a facility map with equipment and worker location.Īfter completing a noise map, identify the loudest areas on the map and the equipment in those areas.Measure the average noise level in each location for at least 30 seconds to capture non-continuous noise. Move through the facility taking SLM measurements every few feet to show where the noise level changes.Take measurements during the typical operating situation (for example, when all the equipment is running).Wear hearing protection while taking measurements in noisy areas.

DECIBEL METER SCALE HOW TO

How to draw a noise map to locate problem areas and equipment:

Define zones where employers should require hearing protectors.

Determine the equipment or areas to focus on in mitigating noise or limiting access.

Dosimeters average noise levels over time and calculate a noise dose. When noise levels vary quite a bit or when workers are very mobile, use personal noise dosimeters to assess a worker’s noise exposure. When noise levels in an area are fairly constant, you can use SLMs to estimate a worker’s average noise exposure.

get a general idea of frequency content.

discover how much noise is coming from specific equipment.

The two basic instruments for characterizing noise are sound level meters (SLMs) and dosimeters. A noise dose of 100% or more means that a worker has exceeded their daily limit.

Noise dose: The percent of allowable noise exposure.

Time Weighted Average (TWA) sound level: The noise level averaged over an eight-hour period.

Sound level: The measured noise level at a given point in time.

Occupational noise measurements are usually reported in the following ways: To properly control and reduce noise in the workplace, you should know:

Decibel meter scale