If this were a critical problem, a more careful anal-
more critical situation because an SIL of 55 dB is
ysis could take into account the wall sections
desired. The wall area to each Engine Room is 30
occupied by the electric shafts (reducing the wall
ft. by 8 ft., excluding the electrical shafts. The wall
2
facing Engine Room No. 1 has a 72-ft. viewing
area and therefore reducing slightly the trans-
mitted noise), and it could permit excess noise at
window (planned to be of l/2-in. safety plate glass)
and the wall facing Engine Room No. 2 has a
the 500-Hz band as long as the arithmetic average
2
48-ft. viewing window. A hung acoustic tile ceiling
of the SPLs of all three SIL bands does not exceed
is planned, and an additional side wall area of 500
60 dB. Also, if this were a critical problem, an
8-in. - or 10-in. -thick solid concrete block wail would
ft. will be covered with sound absorption panels of
NRC = 0.75 to 0.85. The Room Constant is first es-
exceed the requirement. It would be reasonable
here to have the planned 10-in. hollow-core con-
timated, by using DD Form 2295 as shown in figure
crete block walls. The A-weighted sound level is
415. The initial study of TL requirements is then
well under the 84-dB(A) maximum limit.
carried out with DD Form 2298. This is shown in
(6) Wall selection for Control Room. This is a
figures 4-16 and 4-17.
4-21
Previous Page
