Air For Ventilation And Combustion - Burnham 8HE Series Application Instructions

1

Air for Ventilation and Combustion

!
WARNING
Provide combustion and ventilation air in
accordance with section "Air for Combustion
and Ventilation", of National Fuel Gas
Code, ANSI Z223.1/NFPA 54, or applicable
requirements of local building codes.
!
CAUTION
Do not store flammable liquids, combustible
materials, or potential combustion air
contaminants in boiler area.
1.1 Insufficient ventilation air may cause incomplete
combustion, poor ignition, accumulation of soot
in the boiler, or the production of toxic gases.
Many service calls for dirty boilers, nuisance
lock outs, noisy ignition, or obnoxious odors are
traceable to insufficient ventilation air.
1.2 The information below is from the National Fuel
Gas Code, ANSI Z223.1/NFPA 54. See NFPA 54
for further details.
1.3 Determine the boiler input required to the
system. Determine load of the heated space
using methods contained in the ASHRAE
Handbook or other engineering methods. If
domestic water heater is to be added, calculate
the added boiler capacity as described in
paragraph 3.21 of this manual. Size boilers per
total net rating as shown on Table 1-2.
1.4. Determine Required Room Volume
Air openings are required for all boiler rooms
smaller than 50 ft. / 1,000 Btu/hr.
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Table 1-1: Air for Combustion and Ventilation
Free Area of Each Air Opening*
1 in / MBH
2
2 in / MBH
2
1 in / 4 MBH (0.25in
2 2
1 in / 2 MBH (0.5 in
2 2
1 in / 3 MBH (0.33 in
2 2
* Use total input from all appliances.
** Single opening free area must also be not less than sum of areas of all vent connectors in space.
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Indoor Air
/ MBH)
/ MBH) Outdoor Air
/ MBH)**
8HE
Multiple Boiler Application Instructions
If it is known or suspected that the air infiltration
rate is less than 0.4 ACH (air changes per hour),
the minimum required room volume is calculated
using the formula:
Room Volume
Required per
1,000 Btu/hr
Adjacent rooms may be included in the boiler
room volume if the adjacent room(s) are
communicating directly (no doors) or have
internal air openings sized per Table 1-1.
1.5 .Determine Free Area of Air Openings
Size air openings for the total appliance input
as shown in Table 1-1. See also Figure 1-3 and
Figure 1-4.
Upper Opening or Single Opening – Opening
shall commence within 12 in. of the top of the
enclosure. See also paragraph 1.7.h.
Lower Opening – Opening shall commence
within 12 in. of the bottom of the enclosure. See
also paragraph 1.7.h.
1.6 Louvers, Grilles, and Screens - The required
size of openings for combustion, ventilation, and
dilution air shall be based on the net free area
of each opening. Where the free area through
a design of louver, grille, or screen is known, it
shall be used in calculating the size opening
required to provide the free area specified.
Where the louver and grille design and free
area are not known, it shall be assumed that
wood louvers have 25 percent free area, and
metal louvers and grilles have 75 percent free
area. Nonmotorized louvers and grilles shall be
fixed in the open position. Screens shall not be
smaller than 1/4 in. mesh.
Air Opening Type
Combining Space on the Same Story.
Two Openings
Combining Spaces in Different Stories.
Vertical Ducts or Direct Communication
(vertical or horizontal).
Two Openings
Horizontal Ducts.
Vertical or Horizontal Ducts or Direct
Single Opening
Communication (vertical or horizontal).
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ACH
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