AS NZS 1269.4:2014 pdf free

AS NZS 1269.4:2014 pdf free.Occupational noise management
A threshold shift greater than or equal to 15 dB at 500, 1000，1500 or 2000 Hz, or greater than or equal to 20 dB at 8000 Hz in either ear; a change in mean threshold greater than or equal to 10 dB at 3000 and 4000 Hz, or greater than or equal to 15 dB at 6000 Hz in either ear; or a change in average threshold at 3000, 4000 and 6000 Hz greater than or equal to 5 dB in either ear.
Audiometers shall be constructed and calibrated at least to the requirements of Type 4 monitoring air conduction pure-tone manual and automatic recording audiometers as specified in AS IEC 60645.1 (IEC 60645-1). They shall be maintained and regularly calibrated according to the requirements of Clause 5.3. Computer-controlled audiometers shall be constructed so that they meet the requirements concerning monitoring air conduction pure-tone manual audiometers and give results equivalent to those obtained by manual pure-tone audiometry.
An experienced tester with normal hearing shall listen carefully for distortions, attenuator and tone-switch transients and other unwanted sound from the audiometer at a minimum of three attenuator settings, separated by at least 20 dB, at all test frequencies. If any unwanted sounds from the audiometer are heard, the audiometer shall be withdrawn from service for inspection and repair.
Take an audiogram of a person having known stable hearing, with hearing threshold levels not exceeding 25 dB at each test frequency, and compare the test results with the known audiogram. If the results indicate hearing threshold level differences that equal or exceed 10 dB at any frequency the audiometer shall be withdrawn from service and subjected to an objective calibration check or basic calibration.
The outcome of measurement of the acoustical environment in which audiometry is carried out is referred to as the ambient noise level’, both in the case where audiometry is carried out without an audiometric booth and where audiometry is carried out within an audiometric booth. In the case where audiometry is carried out in an audiometric booth, the term external ambient noise level refers to the outcome of measurement of the acoustical environment surrounding the booth.AS NZS 1269.4 pdf free download.