EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE
(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)
ROOF TERMINATED
EXHAUST PIPE
VENTILATION LOUVERS
(Each end of attic)
\ II I
OUTLET
AIR
IINATED
JST PIPE VENTIL
LOU_.
( ":RNATE _6I MP_ INLET (For un
ATION) AIR %IL." crawl .'pace)
/
I
_1 I" rrrm
NOTE-The inlet and outlet air openings shall each have a free area
of at least one square inch per 4,000 Btu (645mm2per 1.17kW) per
hour of the total input rating of all equipment in the enclosure.
FIGURE 4
If air from outside is brought in for combustion and ventila-
tion, the confined space must have two permanent open-
ings, One opening shall be within 12 inches (305 mm) of the
top of the enclosure and one opening within 12 inches (305
mm) of the bottom. These openings must communicate di-
rectly or by ducts with the outdoors or spaces (crawl or at-
tic) that freely communicate with the outdoors or indirectly
through vertical ducts, Each opening shall have a minimum
free area of 1 square inch (645 mm 2) per 4,000 Btu (1.17
kW) per hour of total input rating of all equipment in the en-
closure, See figures 4 and 5. When communicating with
the outdoors through horizontal ducts, each opening shall
have a minimum free area of 1 square inch (645 mm2) per
2,000 Btu (.56 kW) per total input rating of all equipment in
the enclosure, See figure 6,
When ducts are used, they shall be of the same cross-sec-
tional area as the free area of the openings to which they
connect. The minimum dimension of rectangular air ducts
shall be no less than 3 inches (75 mm). In calculating free
area, the blocking effect of louvers, grilles, or screens must
be considered. If the design and free area of protective cov-
ering is not known for calculating the size opening required,
it may be assumed that wood louvers will have 20 to 25 per-
cent free area and metal louvers and grilles will have 60 to
75 percent free area, Louvers and grilles must be fixed in
the open position or interlocked with the equipment so that
they are opened automatically during equipment opera-
tion,
EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE
(All Air Through Ventilated Attic)
7
ROOF TERMINATED VENTILATION LOUVERS
EXHAUST PIPE (Each end of attic)
TERMINATED
EXHAUSTPIPE
(ALTERNATE
LOCATION)
INLET AIR
(Ends 12"above
bottom)
NOTE-The inlet and outlet air openings shall each have a free area of
at least one square inch per 4,000 Btu (645mm2per 1.17kW) per hour
of the total input rating of all equipment in the enclosure.
FIGURE 5
EQUIPMENT IN CONFINED SPACE -
ALL AIR FROM OUTSIDE
ROOF TERMINATED
EXHAUST PIPE
SIDE WALL
TERMINATED
EXHAUSTPtPE
(ALTERNATE
LOCATION)
NO TE-Each air duct opening shaft have a free area of at least one
square inch per 2,000 Btu (645mm2per. 59kW) per hour of the total
input rating of all equipment in the enclosure, ff the equipment room
is located against an outside wall and the air openings communi-
cate directly with the outdoors, each opening shaft have a free area
of at least 1 square inch per 4,000 Btu (645mm 2per 1.17kW) per
hour of the total input rating of aft other equipment in the enclosure.
FIGURE 6
Page 8
To Next Page
Loading...
