OSHA Noise Compliance Testing
OSHA Noise Compliance Testing is becoming a more frequently requested service by Sonic-Shield’s clients. As described in a previous application note, Deciphering OSHA Noise Regulations, the US Occupational Safety and Health Administration (OSHA), requires an employer to administer a hearing conservation program whenever employees are exposed to noise levels that are at or above an eight-hour time-weighted average (TWA) of 85 dBA (the so-called “Action Level”) or, equivalently, a dose of 50 percent of the maximum permissible exposure level (PEL) of 90 dBA.
Sonic-Shield assists employers by conducting noise surveys within their facilities to identify potential areas of concern and if necessary, implement noise abatement solutions and provide soundproofing products to reduce the noise to within acceptable limits.
One approach to evaluating employee noise exposure levels is to outfit employees who are at high risk of being exposed to high noise levels with a dosimeter, which they wear during their work shift. A noise dosimeter is an electronic device, the size of a cell phone, that measures and records acoustic levels. The noise dosimeter does not record acoustical data, but only provides a reading of overall decibel levels at certain times. At the end of a work shift, an audiologist reviews the data to determine if the employee was subject to levels that exceed the OSHA maximum PEL.
Some employers have required that each piece of plant equipment emit no more than 85 dBA of noise at any given time during normal operation. Such a requirement, however, is not a guarantee that employees will be subject to noise within the OSHA maximum PEL, because noise from different sources tends to add logarithmically. For example, if there are four pieces of equipment in close proximity to one another emitting 85 dBA, the combined noise level would be 91 dBA, which would exceed the OSHA maximum PEL if an employee was subject to this noise over an 8-hour period.
Our approach through our OSHA noise compliance testing is to identify loud equipment and implement the appropriate soundproofing solution to ensure performance at or below the OSHA Action Level of 85 dBA, considering noise from all of the equipment in the immediate vicinity. The employer therefore does not need to administer a hearing conservation program, and hearing protection will not be required by employees per OSHA guidelines.
The key to our OSHA noise compliance testing is to perform a detailed acoustic site survey of the facility and equipment. Rather than just measuring the overall noise levels using a Class 2 SLM (which is the minimum requirement for OSHA), we use a more accurate Class 1 SLM and obtain the one-third octave band frequency spectra. Acoustic data is then assembled to create a “sound map” of the facility that shows the overall sound levels as a function of location within the facility (Figure 1).
Distinct “sound zones” are then created which are designed to assist the facility manager to establish procedural guidelines or implement sound attenuation for high risk areas. In certain cases, we may determine that more in-depth continuous monitoring is required, where we can install acoustic data loggers that will store noise information at regular intervals. These data loggers can later be downloaded and analyzed by our acoustic engineers.
Sonic-Shield has an engineering staff with advanced technical capabilities that can assist employers in conducting OSHA noise compliance testing. If necessary, we can also develop and supply the appropriate sound abatement materials and products to reduce the noise within your facilities to comply with acceptable OSHA established limits.