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Asphyxiation,fire hazard.Do not obstruct air
openingsto combustionarea. Followinstructions
below,to maintainadequatecombustionair.
Install
outside
air intake
if used with a fireplace
or
kitchen
or bathroom
exhaust
fan. These devices
rob
boiler and water
heater
of combustion
air.
I.
Determine volume of space (boiler room), Rooms
communicating
directly with the space in which
appliances are installed, through openings not furnished
with doors, are considered a part of the space,
Volume (ft 3) = Length (ft.) x Width (ft.) x Height (ft.)
2.
Determine total input of all appliances in the space,
Add inputs of all appliances in the space and round the
result to the nearest 1000 BTU/hr,
3.
Determine type of space. Divide Volume by total input
of all appliances in space, If the result is greater than
or equal to 50 ft3/1000 BTU/hr, then it is considered
an unconfined
space,
If the result is less than 50
ft3/1000 BTU/hr, then the space is considered a
confined space.
4.
When a boiler is located in an unconfined space of a
conventionally
constructed
building, fresh air infiltration
through cracks around windows and doors normally
provides adequate air for combustion and ventilation.
5.
Provide outdoor air for boiler located in a confined
space or an unconfined space in a building of unusually
tight construction.
Outdoor air may be provided with
the use of two permanent
openings which communicate
directly or by duct with the outdoors or spaces
(ventilated
crawl or attic) freely communicating
with
the outdoors. Locate one opening within 12 inches
of top of space. Locate remaining
opening within 12
inches of bottom of space. Size each opening per the
following:
A. Direct communication
with
outdoors:
Minimum free area of 1 square inch per 4,000 BTU
per hour input of all equipment
in space,
Bg
Vertical
Ducts: Minimum free area of 1 square
inch per 4,000 BTU per hour input of all equipment
in space. Duct cross-sectional
area shall be same
as opening free area.
Cg
Horizontal
Ducts: Minimum free area of 1 square
inch per 2,000 BTU per hour input of all equipment
in space. Duct cross-sectional
area shall be same
as opening free area.
Alternate
method
for boiler
located within
confined
space: Use indoor air if two permanent
openings communicate directly with additional space(s)
of sufficient volume such that the combined volume of
all spaces meet criteria for unconfined space. Size each
opening for minimum free area of i square inch per
1,000 BTU per hour input of all equipment in spaces,
but not less than 100 square inches.
6.
Louvers and Grilles of Ventilation
Ducts
A,
B,
All outside openings should be screened and
Iouvered. Screens used should not be smaller than
1/4 inch mesh. Louvers will prevent the entrance of
rain and snow.
Free area requirements
need to consider the
blocking effect of louvers, grilles or screens
protecting the openings. If the free area of the
louver or grille is not known, assume wood louvers
have 20-25% free area and metal louvers and grilles
have 60-75% free area.
C, Louvers and grilles must be fixed in the open
position, or interlocked
with the equipment to open
automatically
during equipment operation,
Figure
3 - Air Openings
For Boiler
Located
fn
Confined Space (Utility
Room)
VEN]
EA]
ZNG
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