important:

A noise dosimeter is the basis for determining total daily noise exposure for employees. However, where there is constant noise levels, the employer may estimate employee noise exposure using measurements from a sound level meter. Calculation of the employee noise exposure must be consistent with WAC 296-307-63415.

(1) The employer must include all:

(a) Workplace noise from equipment and machinery in use;

(b) Other noise from sources necessary to perform the work;

(2) The employer must use a noise dosimeter when necessary to measure employee noise dose.

(3) The employer must use a sound level meter to evaluate continuous and impulse noise levels.

(4) The employer must identify all employees whose exposures equal or exceed the Noise Evaluation Criteria as follows:

Noise Evaluation Criteria

Criteria	Description	Requirements
85 dBA TWA8	Full-day employee noise exposure dose. If you have one or more employees whose exposure equals or exceeds this level, you must have a hearing loss prevention program	– Hearing protection – Training – Audiometric testing
90 dBA TWA8	Full-day employee noise exposure dose. If you have one or more employees whose exposure equals or exceeds this level, you must reduce employee noise exposures in the workplace	Noise controls (in addition to the requirements for 85 dBA TWA8)
115 dBA measured using slow response	Extreme noise level (greater than one second in duration)	– Hearing protection – Signs posted in work areas warning of exposure
140 dBC measured using fast response	Extreme impulse or impact noise (less than one second in duration)	Hearing protection

PDFWAC 296-307-63410

Measure employee noise exposure.