1. (1) You must use pure tone, air conduction, hearing threshold examinations, with test frequencies including as a minimum 500, 1000, 2000, 3000, 4000, and 6000 Hz.

   1. (a) Tests at each frequency must be taken separately for each ear;
   2. (b) Supra-aural headphones must be used.
2. (2) You must conduct audiometric tests with audiometers (including microprocessor audiometers) that meet the specifications of, and are maintained and used according to, American National Standard Specification for Audiometers, S3.6-1996.

3. (3) You must check the functional operation of the audiometer each day before use by doing all of the following:

   1. (a) Make sure the audiometer's output is free from distorted or unwanted sound;
   2. (b) Test either a person with known, stable hearing thresholds or a bio-acoustic simulator;
   3. (c) Perform acoustic calibration for deviations of 10 dB or greater.
4. (4) You must check audiometer calibration must be checked acoustically at least annually to verify continued conformance with ANSI S3.6-1996. Test frequencies below 500 Hz and above 6000 Hz may be omitted from this check.
5. (5) You must perform an exhaustive calibration must be performed at least every two years according to the American National Standard Specification for Audiometers, S3.6-1996. Test frequencies below 500 Hz and above 6000 Hz may be omitted from the calibration.

6. (6) You must provide audiometric test rooms that meet the requirements of ANSI S3.1-1999 American National Standard Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms using the following table of maximum ambient sound pressure levels:

   Table 4

   Maximum Ambient Sound Pressure Levels

   Frequency (Hz)	500	1000	2000	4000	8000
   SoundPressureLevel (dB)	40	40	47	57	62

   Note:

   The American Industrial Hygiene Association and National Hearing Conservation Association recommend conducting audiograms using the requirements of ANSI S3.1-1999 American National Standard Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms with adjustments at only 500 Hz and below.

[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050. WSR 15-23-086, § 296-817-40035, filed 11/17/15, effective 12/18/15. Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, and 49.17.060. WSR 03-11-060, § 296-817-40035, filed 5/19/03, effective 8/1/03.]