Why do we monitor employees for noise exposures?

Hearing losses of 10 dBA or more are now required to be recorded on employer’s OSHA 300 Logs. Workers compensation cases involving hearing loss can be costly. Noise monitoring is used to evaluate employee exposures to noise, to assist in the design and evaluation of control measures to reduce employee exposures, and to document compliance with OSHA regulations (29 CFR 1910.95, Occupational Noise Exposure).

 

Hofman does a significant amount of monitoring for noise exposures. We currently own seven Quest dosimeters, and a sound level meter. We also have calibrators for daily on-site calibration of instruments. Factory calibration is conducted annually.

 

Procedures for Noise Monitoring

Noise can be monitored using either Personal Dosimeters or Sound Level Meters. Personal noise dosimetry is the preferred method used to evaluate worker exposures to noise. This is also the method used to determine compliance with OSHA regulations.

 

Personal Dosimetry is conducted using a dosimeter (a small device with an attached microphone). The dosimeter is attached to the employee and the microphone placed within the hearing zone. The device records the noise levels that the employee is exposed to throughout the entire shift. Exposure results are calculated and compared to an 8-hour Time Weighted Average (TWA).

 

Sound Level Surveys are taken using a Sound Level Meter. Readings are used to obtain a map of the work environment, to locate sources of noise exposures, and to evaluate the effectiveness of control measures. Sound Level Maps are created by recording real time noise levels in relation to specific areas within a given location.

 

What is required?

When noise monitoring shows that an employee is exposed to an 8-hour TWA of 85 dBA or greater, he or she must be covered by the employer’s Hearing Conservation Program. This includes annual audiograms and training covering the hazards of noise exposure, and the proper use of Personal Protective Equipment (PPE). When noise monitoring shows that an employee is exposed to an 8-hour TWA of 90 dBA or greater, the employer must document that engineering controls were investigated and implemented (if feasible).

 

Other things that employers can do to prevent hearing damage is to implement administrative controls or make the use of PPE mandatory. Administrative controls include limiting the amount of time an employee can work in a noisy area. That employee is then removed from the noisy area and scheduled for work in a quiet area for the remainder of his or her shift. There are two types of PPE used to control employee noise exposures, ear plugs and ear muffs. Both types of PPE are used as a temporary solution until engineering controls can be implemented or on a more extended basis if the noise exposure can not be reduced.

 

Engineering/Operational Controls

When employee exposures exceed 90 dBA TWA, and especially if exposures exceed 95-100 dBA, Hofman will recommend the investigation of controls to comply with 1910.95 (b). Engineering controls include enclosures for noisy equipment, vibration dampening, enclosing worker control stations (isolation), and sound transmission absorption. Sometimes operational controls, or engineering controls in combination with administrative controls will do the trick.

 

Audiogram Follow-up

Hofman is available to assist in evaluating and interpreting employee annual audiograms, and assist in follow-up with the hearing test provider. Assistance with OSHA Log requirements is also available.

Hofman Safety and Industrial Hygiene Consulting, Inc.

Noise Monitoring