Methods for Evaluating Noise Exposures: OH&S

Methods for Evaluating Noise Exposures : Occupational Health and Safety Magazine
Understanding noise exposure evaluations, from basic area evaluations to the intricacies of equipment precision and the role of smartphone apps in noise measurements. By Gregory Boothe, Nov. 2023

Noise exposures and standard threshold shifts have been present in general industry and construction sites since the Occupational Safety and Health Administration was founded. In fact, many safety professionals will be responsible for dealing with noise hazards at least once in their careers.

Although this is a common challenge, many safety professionals have never received any training on sampling for noise exposures. Understanding the noise sampling process can be very important in accurately evaluating noise exposures and implementing effective controls.

Basic Evaluation of Area
A common approach to evaluating noise exposures is to walk around the facility with a sound level meter (SLM) and record noise levels as area samples. The readings are sometimes used to produce a “sound map” of the facility showing areas where readings were above or below the action level and the permissible exposure limit (PEI), which is the noise exposure OSHA allows for a workday. In some cases, the readings are used to evaluate compliance with the OSHA standard, the need for a hearing conservation program and the need to implement controls including the use of hearing protection. This approach can be acceptable if the readings are representative of the workers’ actual exposures.

Acceptability of area samples typically depends on the mobility of the workers and the homogeneity of sound levels in the work areas. When the workers are mobile throughout the workday, and/or the sound levels change frequently during the work shift, area readings with an SLM may not be representative of actual exposures and another evaluation should be used.

Noise dosimeters are commonly used to measure personal exposures to noise in a workplace when mobility is an issue. The noise dosimeter can be worn by the worker and will provide a time-weighted average (TWA) exposure for the worker wearing the dosimeter. This would include the integration of exposures during breaks. Noise dosimeters are typically more costly than SLMs and can be a disincentive for many companies.

Meeting the Standards
It’s pertinent to understand the performance characteristic of the different types of instruments that can be used for noise exposure evaluation. SLMs and dosimeters used for OSHA compliance must meet the specifications in American National Standards Institute (ANSI) Standard S1.4 (OSHA, 2013). The ANSI standard sets tolerances for performance and accuracy (OSHA, 2013). There are three levels of precision in the ANSI Standard, Types 0, 1 and 2. Type 0 is the most precise and Type 2 is the least precise. Type 0 SLMs are used in laboratories so this article will not discuss them in relation to field sampling.

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