Fresh Air For Combustion - ECR Dunkirk PWB Series Manual

Air openings to combustion area must
!
not be obstructed. Following instructions
below, adequate combustion air can be
maintained.
Provide combustion air and ventilation air in
accordance with the section "Air for Combustion and
Ventilation," of the National Fuel Gas Code, ANSI
Z223.1 / NFPA 54, or applicable provisions of local
building codes.
Provide make-up air where exhaust fans, clothes
dryers, and kitchen ventilation equipment interfere
with proper operation.
National Fuel Gas Code recognizes several methods
of obtaining adequate ventilation and combustion air.
Requirements of the authority having jurisdiction may
override these methods.
• Engineered Installations. Must be approved by
authority having jurisdiction.
• Mechanical Air Supply. Provide minimum of
0.35 cfm per Mbh for all appliances located
within space. Additional requirements where
exhaust fans installed. Interlock each appliance
to mechanical air supply system to prevent main
burner operation when mechanical air supply
system not operating.
• All Indoor Air. Calculate minimum volume for all
appliances in space. Use a different method if
minimum volume not available.
A. Standard Method. Cannot be used if known
air infi ltration rate is 0.40 air changes per
hour. See Table 1 for space with boiler only.
Use equation for multiple appliances.
Volume ≥ 50 ft
Table 1 - Minimum Room Volume, Indoor Air Only*
Standard
Input Mbh
Method
37.5 1875
70 3500
105 5250
140 7000
175 8750
210 10500
245 12250
280 14000
* Table values based on boiler only. Add volume for any additional appliances.

FRESH AIR FOR COMBUSTION

WARNING
x Total Input [Mbh]
3
Known Air Infi ltration Rate Method (Air Changes Per Hour)
0.1
7875
14700
22050
29400
36750
44100
51450
58800
B. Known Air Infi ltration Rate. See Table 1
for space with boiler only. Use equation
for multiple appliances. Do not use an air
infi ltration rate (ACH) greater than 0.60.
Volume ≥ 21 ft
C. Refer to National Fuel Gas Code for opening
requirements between connected indoor
spaces.
• All Outdoor Air. Provide permanent opening(s)
communicating directly or by ducts with outdoors.
A. Two Permanent Opening Method. Provide
opening commencing within 12 inches of top
and second opening commencing within 12
inches of bottom of enclosure.
B. One Permanent Opening Method. Provide
opening commencing within 12 inches of top
of enclosure. Provide minimum clearance of
1 inch on sides/back and 6 inches on front
of boiler (does not supersede clearance to
combustible materials).
C. Refer to National Fuel Gas Code for additional
requirements for louvers, grilles, screens and
air ducts.
• Combination Indoor and Outdoor Air. Refer
to National Fuel Gas Code for application
information.
0.2 0.3
3938 2625
7350 4900
11025 7350
14700 9800
17375 12250
22050 14700
25725 17150
29400 19600
4
⁄ACH x Total Input [Mbh]
3
Direct communication with outdoors or
communicating through vertical ducts.
Provide minimum free area of 1 in² per 4
Mbh of total input rating of all appliances
in enclosure.
Communicating through horizontal ducts.
Provide minimum free area of 1 in² per 2
Mbh of total input rating of all appliances
in enclosure.
0.4 0.5
1969 1575
3675 2940
5513 4410
7350 5880
9188 7350
11025 8820
12863 10290
14700 11760
0.6
1313
2450
3675
4900
6125
7350
8575
9800