be initiated without such a survey. For example, a noise survey is unnecessary in the
a. When personnel have difficulty communicating by speech while they are in
the noise area.
b. When personnel hear noises or ringing sounds in their ears after working in
the noise area for several hours.
c. When personnel experience temporary loss of hearing, which muffles speech
and certain other sounds, after several hours of exposure to the noise.
NOTE: In borderline cases, a noise survey is recommended.
THE NOISE SURVEY
The purpose of the noise survey is to evaluate the exposures to noise in the work
place in relation to interference with speech, worker comfort, and hearing loss. Another
important purpose served is the collection of information for use in designing controls.
In making noise measurements, the following points are important.
a. At all locations where noise makes it difficult for two persons with good
hearing to converse at close range, tests should be made with a sound level meter.
The average, overall level is determined by taking several meter readings at each
location. In general, when it is necessary to shout in order to be heard intelligibly at a
distance of 1 foot, the noise level is at least 60 dB(A), and probably even higher.
b. Steady noises from several sources, varying in their composition and
frequency spectra, can lead to hearing loss. It is therefore essential that such noise be
broken down into its several components and analyzed. This can be done by using an
octave band analyzer with the sound level meter.
c. Noise levels should be measured at the approximate position of the worker's
more exposed ear. Repeated measurements should be made to take into account
variations in noise levels resulting from changes in operating schedules or work
d. Repeated measurements should be taken in order to accurately determine
the manner in which noise levels are distributed throughout the workday.
e. Many operations and areas that are sources of hazardous noise are common
to most Army installations and should be the site of sound surveys. These include the
interiors of tanks, personnel carriers, and truck cabs; the vicinity of field electrical
generator sets; machine shops, carpenter shops; sheet metal shops; engine repair and
testing shops; weapons ranges; areas in which air driven tools are used; aircraft in
operation on the ground and in the air; and aircraft engine test facilities.