Engine Room No. 1 contains two engines and has
Room and Offices are served by a separate system
space for a third. Each engine has a 3500-hp rating,
to eliminate the possible feed-through of Engine
Room noise into the quieter parts of the building.
operates at 450 rpm, and can use either natural gas
o r diesel fuel. T h e s e in-line engines are
The engine air inlet in the wall of Engine Room
turbocharged, with approximately 15-ft.-long in-
No. 2 is always open in the event of failure of the
take ducts to the air cleaners located out of doors,
building ventilation system.
as shown. The engine exhausts are fed through
b. Sound level requirements.
50-ft. pipes to "best grade" low-pressure-drop ex-
(1) Engine Rooms. There are no current state-
haust mufflers, also out of doors. Engine Room No.
of-the-art. developments that will reduce engine
2 contains one 900-hp V-12 engine that operates at
room noise to the nonhazardous levels of less than
1800 rpm and one 1600-hp V-16 engine that oper-
85 dB(A), so personnel using these rooms must use
ates at 900 rpm. Another V-16 engine may be
hearing protection equipment (approved ear plugs
added later in this room. The V-12 engine has a
or ear muffs) when their daily exposures exceed
turbocharger that draws intake air directly from
the allowable limits (para 3-4d of the N&V
the room through an air filter chamber, and the
manual).
V-16 engine is fitted with a Roots Blower that
(2) Maintenance Shop. Sound levels here shall
draws air from the room without benefit of a muf-
not exceed 84 dB(A), for purposes of hearing pro-
fler intake arrangement. Engine combustion air is
tection, and it is preferred that the speech inter-
drawn into this room through a side wall opening
ference level (SIL) due to Engine Room noise not
that is to be fitted with a muffler if necessary.
exceed 60 dB when Engine Room doors are closed
These engines are fitted with "best grade" exhaust
(para 3-2d of the N&V manual describes SIL).
mufflers through 30-ft.-long exhaust pipes. Low-
(3) Control Room. Sound levels here shall not
p r e s s u r e - d r o p mufflers are used with the
exceed 84 dB(A), and it is preferred that the SIL
engines, and high-pressure-drop
turbocharged
due to Engine Room noise not exceed 55 dB when
mufflers are used with the Roots Blower engines.
all engines, existing and future, are in operation.
(l) Personnel access doors are provided be-
(4) Offices. Engine Room noise heard in the of-
tween the Maintenance Shop and the Engine
fices shall not exceed NC40 levels when all doors
Rooms, emergency exit doors are provided in the
are closed (para 32a of the N&V manual).
south walls of the Engine Rooms, and large
(5) On-base housing. Power plant noise shall
equipment-access roll doors are provided between
not exceed NC25 levels indoors at the base hous-
the Engine Rooms and a large "Receiving, Stor-
ing located about 1200 ft. to the east of the plant,
age, Transfer Room" across the south side of the
when all exterior doors of the plant are closed.
building.
c. Engine Room noise levels. DD Form 2304 is
(2) The Offices and Lunch Room and Lounge
used to estimate the PWL of each engine. DD
at the north side of the building are partially pro-
Form 2295 (Room Constant by Estimation Meth-
tected `from Engine Room noise by "buffer" areas:
od. ) is used to estimate the Room Constant of each
The Toilet and Locker Rooms protect the Lunch
room. DD Form 2296 (Mechanical Equipment
Room and Lounge, and the corridor protects the
Room SPL Caused by Equipment) and DD Form
group of Offices.
2297 (Summation of All Equipment SPLs on One
(3) The Maintenance Shop and the second-floor
Wall or Surface of the ME R.) are used to estimate
Control Room overlooking the two Engine Rooms
the SPLs at the Engine Room walls that are com-
must be evaluated in order to determine the re-
mon to the other rooms of interest (the Mainte-
quirements for walls, doors, and windows common
nance Shop, the Control Room, and the corridor
with the Engine Rooms, with special emphasis be-
separating the Offices from Engine Room No. 2).
ing given to the size and make-up of the viewing
(1) Engine PWLs. The accompanying filled-in
windows in order to achieve an acceptable "SIL"
copies of DD Form 2304 give the estimated PWLs
(speech interference level) condition in the Control
of the three noise components of each of the three
Room because of the present and future engines in
engine types involved here. Only the engine casing
the two Engine Rooms.
noise (Part A) radiates into the Engine Rooms. For
(4) A Mechanical Equipment Room provides
identification, see figures 42 through 44 for
ventilation air for the Engine Rooms as the outside
samples.
and inside air temperatures dictate. The Control
4-2
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