Specifications

9
C. PROVIDE COMBUSTION AND VENTILATION
AIR. Local and National Codes may apply and should
be referenced.
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1. Determine volume of space (boiler room). Rooms
communicating directly with the space in which
the 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 per hour.
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 ft
3
/1000 BTU per hour,
then it is considered an unconfi ned space. If the
result is less than 50 ft
3
/1000 BTU per hour then the
space is considered a confi ned space.
4. For boiler located in an unconfi ned space of a
conventionally constructed building, the fresh
air infi ltration through cracks around windows
and doors normally provides adequate air for
combustion and ventilation.
5. For boiler located in a confi ned space or an
unconfi ned space in a building of unusually tight
construction, provide outdoor air.
a. Outdoor air for combustion may be provided
with an optional Burnham MPO (V8) Inlet Air
Accessory Kit, Part Number 611280031 (only
available and suitable for use on Beckett AFG
with burner enclosure cover burner). See
Section V for installation details.
or
b. Outdoor air may be provided with the use of two
permanent openings which communicate directly
or by duct with the outdoors or spaces (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. Minimum dimension
of air opening is 3 inches. Size each opening per
following:
i. Direct communication with outdoors.
Minimum free area of 1 square inch per
4,000 BTU per hour input of all equipment
in space.
ii. 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.
iii. 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
confi ned space. Use indoor air if two
permanent openings communicate directly
with additional space(s) of suffi cient volume
such that combined volume of all spaces
meet criteria for unconfi ned space. Size each
opening for minimum free area of 1 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. All outside openings should be screened and
louvered. Screens used should not be smaller
than 1/4 inch mesh. Louvers will prevent the
entrance of rain and snow.
b. 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 percent free area and metal
louvers and grilles have 60-75 percent free area.
c. Louvers and grilles must be fi xed in the open
position, or interlocked with the equipment to
open automatically during equipment operation.