TM5-805-9/AFM
88-20/NAVFAC
DM-3.14
typical work spaces, and the design portion of the
terprets the imperfectly heard speech. Long sen-
manual indicates the methods of achieving these
tences are fatiguing to the talker, and long or unfa-
noise criteria, relative to engine-produced noise.
miliar words are not understood by the listener.
Engine noise is accepted as a necessary part of the
Engine room noise usually discourages long sen-
power plant, but this noise is unwanted almost ev-
tences, unfamiliar terms, and complex conversa-
erywhere outside the engine room--hence, the em-
tions. Quieter surroundings are required for
phasis on adequate noise reduction through archi-
lengthy, precise speech communication. The manu-
tectural and engineering design to bring this noise
al addresses this problem.
down to an innocuous, unintruding "background" in
c. Interference with warning signals. In some
those areas requiring controlled degrees of
noisy work areas, warning bells or horns and an-
quietness.
nouncement or call systems are turned up to such
f. Community noise problems. Rest, relaxation,
high levels that they are startling when they come
and sleep place severe requirements on the noise
"on" abruptly. In fact, because they must pene-
control problem. Whether the base barracks or on-
trate into all areas of a noisy plant, they are so loud
site housing or slightly hostile off-base neighbors
they "hurt" the ear when a listener happens to be
control the design, the need for relatively quiet
near the signal source. On the other hand, a
surroundings is recognized. The noise criteria and
"weak" bell or call might not be heard at all. Some
acoustic designs provided by the manual are aimed
auxiliary paging and warning systems are sug-
at achieving the background noise levels that will
gested later in the manual.
permit rest, relaxation, and sleep in nearby hous-
ing or residential areas.
d. Difficulty of telephone usage. The noise lev-
els inside most engine rooms completely preclude
g. Summary. These illustrations encompass the
telephone usage. For emergency use as well as for
goals of this manual. In varying degrees, any noise
routine matters, a quiet space satisfactory for reli-
problem encountered will involve hearing preser-
able telephone usage must be provided within or
vation, speech communication, annoyance, or noise
immediately adjoining an engine room. The acous-
intrusion. To a high degree, such problems can be
tical requirements for such a space are covered in
evaluated quantitatively; practical and successful
the manual.
solutions can be worked out with the aid of the
guidelines and recommendations presented in the
e. Noise intrusion into nearby work spaces. Dif-
manual.
ferent types of work spaces require different types
of acoustical environments. The maintenance shop
1-4. Cross reference.
beside a diesel engine room can tolerate a higher
The manual "Noise and Vibration Control for Me-
background noise than the offices and meeting
chanical Equipment" (TM 5-805-4/AFM 88-37/
rooms of the main headquarters of a base. It is pos-
NAVFAC DM-3.10), hereinafter called the "N&V"
sible to categorize various typical work areas ac-
manual, is a complemental reference incorporating
cording to the amount of background noise consid-
many of the basic data and details used extensively
ered acceptable or desirable for those areas. A
in this manual. (See app. B for additional refer-
schedule of "noise criteria" provides a range of
ences and app. C for related publications. )
noise levels considered appropriate for a range of
1-2
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