Working example of a Noise Attenuation Evaluation (1910.95(j)

Following up on a 2012 post about complying with 1910.95(j), I wanted to share a working example of how I document my “hearing protector attenuation” evaluation.  I think the example speaks for it’s self, but if you need a reference as to what this exercise is meant to accomplish please refer to my 2012 post Hearing Protection Attenuation Evaluation, has it been done?  A couple of things to point out: notice that this evaluation was NOT done using a single sample!  

1. We sampled multiple workers over different shifts; ALL samples were done in FULL production mode (i.e., assumed to be the highest noise levels in the areas).  You will notice that I used two (2) different evaluation techniques, and this caused certain HP to pass in one evaluation but fail in the other, so be sure you are comfortable using your evaluation methods. 
2. I highly recommend using OSHA’s “recommended” method that applies a 50% Safety Factor; however, the first method I used below is “legal” under 1910.95.
3. The brands used in the evals below are actual brands used by the facility, and this is NOT an endorsement or opposition to these brands; it is just real-life examples.
4. I ALWAYS use 85 dBA as my attenuation goal rather than 90 dBA. This way, I don’t have two (2) different goals/sets of employees to manage—EVERYONE gets attenuated down to 85 dBA.
5. The state worker’s comp service did sampling, which was actually done by a CIH—SAFTENG does not provide noise sampling services!

Appendix A

Hearing Protector(s) Attenuation

OSHA – Occupational Safety and Health Administration

ACGIH – American Conference of Governmental Industrial Hygienists

dBA – Decibel, A-weighted

1 Exposures at or above 85 dBA indicate the need for hearing conservation. Exposures in BOLD meet or exceed the OSHA AL.

2 OSHA’s occupational noise exposure Action Level for Hearing Conservation Program. [29CFR1910.95]

3 Exposures at or above 90 dBA indicate mandatory hearing protection applies. Exposures in BOLD meet or exceed the OSHA PEL.

4 OSHA’s occupational noise exposure Permissible Exposure Limit [29CFR1910.95]

5 Exposures based on the ACGIH measurement criteria. Exposures in BOLD meet or exceed the ACGIH Threshold Limit Value indicating the need for hearing conservation program including mandatory hearing protection.

6 ACGIH’s occupational noise exposure Threshold Limit Value.

*Short sample time due to starting the monitoring when the XXXXXX Line started up. The result may be an underestimation of the actual exposure when the XXXX Line is at full production due to the XXXXXX Line only running 3-4 hours of the close to 6 hour sample time.

**Short sample time due to starting the monitoring when the XXXX Line started up and the XXXXXX 6 line running out of product.

STEP 1 – Obtain the employee’s A-weighted TWA

STEP 2-  Subtract 7 dB from the NRR, and subtract the remainder from the A-weighted TWA to obtain the estimated A-weighted TWA under the ear protector

PLEASE NOTE:  OSHA Technical Manual RECOMMENDS that a 50% Safety Factor be applied: 

Source:  OSHA Technical Manual, Appendix E – Noise Reduction Rating