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Noise Exposure Testing and Analysis
Exposure to noise at high volumes or for a long duration poses a hazard that can cause temporary or permanent impaired hearing. The California Code of Regulations (CCR) Title 8, Section 5096 defines noise exposure limits for employees as permitted by the California Division of Occupational Safety and Health (Cal/OSHA). The American Conference of Governmental Industrial Hygienists (ACGIH) has also published recommended guidelines for noise limits in the workplace.
Yorke Engineering provides noise exposure sampling, monitoring, and analysis to determine if employees may be exposed to noise exceeding these regulatory and recommended limits during a normal workday. Our team of safety and industrial hygiene specialists can use the results of this analysis to identify the source of a noise hazard and provide options to ensure worker safety. We can provide an analysis of the current hearing protection to determine if it is adequate to protect workers’ hearing and satisfy regulatory requirements. We can determine if a Hearing Conservation Program is needed, as well as provide written program and training support.
Noise exposure levels for an individual employee are measured with a personal noise dosimeter, a data-logging device that is attached to the employee’s shoulder or lapel. The dosimeter provides real-time exposure readings for the duration of the work shift.
A sound level meter is used to measure noise levels in a specific area or identify areas with elevated levels of noise, such as near a manufacturing line or in a room with workstations. This data-logging device provides average, maximum, and peak sounds level readings to evaluate workplace noise levels.
Noise exposure monitoring is recommended whenever work conditions that may cause a noise hazard exist, and should be repeated if the location, amount or type of work changes. Yorke Engineering can assist with this process. Our experts provide sampling equipment and perform on-site testing for all Cal/OSHA limits and ACGIH guidelines. Our analysis of the testing results also provides recommendations to keep employees safe.
Regulatory and Recommended Limits
Noise is measured in A-weighted decibels (dBA), and an 8-hour Time-Weighted Average (TWA) is used to estimate exposure over the duration of one work shift.
Cal/OSHA Regulatory Limits
As described in 8 CCR Section 5096, exposure to continuous noise shall not exceed 115 dBA for longer than 15 minutes. At 115 dBA, the TWA for noise will be reached in 15 minutes. If the variations in noise level involve maxima at intervals of 1 second or less, the noise is to be considered continuous.
Exposure to impulsive or impact noise should not exceed 140 decibels (dB) peak sound pressure level.
For Cal/OSHA, each increase in noise level of 5 dBA will halve the allowable time that an employee can be exposed to that noise level; this is known as the exchange rate.
Additionally, whenever employee noise exposures equal or exceed an 8-hour TWA of 85 dBA, referred to as the action level (AL), the employer shall develop and administer a Hearing Conservation Program (HCP).
ACGIH Recommended Guidelines
ACGIH uses a time-intensity exchange rate of 3 dBA, which means that each increase in noise level of 3 dBA will halve the allowable time that an employee can be exposed to that noise level. This results in a lower 8-hour TWA for noise of 85 dBA, identified as the Threshold Limit Value (TLV).
Exposure to continuous noise shall not exceed 115 dBA for longer than 28 seconds. At 115 dBA, the TWA TLV for noise will be reached in 28 seconds. If the variations in noise level involve maxima at intervals of 1 second or less, the noise is to be considered continuous.
Exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level.
Hearing Conservation Program
An HCP is required by Cal/OSHA when the AL for noise is exceeded, as described in 8 CCR Section 5097. Employees who are part of an HCP must be monitored, provided annual audiometric testing, and given adequate hearing protection. This program is also to include education and training on the effects of noise, purpose of hearing protection, various types of hearing protectors, and instructions on selection, fitting, use, and care. Records must be maintained of all employee testing and training.
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