5- Ventilation & Combustion Air; Requirements - Dunkirk DXL Series Installation, Operation & Maintenance Manual

5.1 Requirements

WARNING
!
Asphyxiation Hazard! Provide enough air openings
to boiler/combustion area to dilute flue gases
and allow for consistent, guality combustion.
Do not obstruct air openings. Follow instructions
below, to maintain adequate combustion air.
Failure to follow these instructions good result in
ignition failure, overheating, carbon monoxide, and
accumulation of flue gases.
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 Sections
8.2, 8.3 or 8.4 of Natural Gas and Propane Installation
Code, CAN/CSA B149.1, or applicable provisions of local
building codes.
Provide make-up air where exhaust fans, clothes dryers,
and kitchen ventilation equipment interfere with proper
operation. If inadequate makeup air is suspected it is
always acceptable to add additional ventilation.
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 [(BTU/HR)/1,000] 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
infiltration rate is 0.40 air changes per hour. See
Table 3 for space with boiler only. Use equation for
multiple appliances.
Volume ≥ 50 ft
3
Table 5-1 - Space With Boiler Only
# Input
Sections BTU/HR
3 59,000
4 92,500
5 120,000
6 149,000
7 175,000
8 205,000
9 235,000
5- VENTILATION & COMBUSTION AIR
x Total Input [( )/1,000 ]
BTU/HR
Known Air Infiltration Rate Method (ACH - Air Changes Per Hour)
Standard
Method
0.1
2950 12390
4625 19425
6000 25200
7450 31290
8800 36960
10250 43050
11750 49350
B. Known Air Infiltration Rate. See Table 5-1 for
space with boiler only. Use equation for multiple
appliances. Do not use an air infiltration rate
(ACH) greater than 0.60.
Volume ≥ 21 ft
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.
… Direct communication with outdoors or
… Communicating through horizontal ducts.
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).
• 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.
National Gas and Propane Installation Code Requires
providing air supply in accordance with:
• Section 8.2 and 8.3 when combination of appliances
has a total input of up to and including 400 [(BTU/
hr)/1,000] (120 kW).
• Section 8.4 when combination of appliances has total
input exceeding 400 [(BTU/hr)/1,000] (120 kW).
• Refer to Natural Gas and Propane Installation Code
for specific air supply requirements for enclosure
or structure where boiler is installed, including air
supply openings and ducts.
Room Cubic Feet Volume
0.2
6195 4130
9712.5 6475
12600 8400
15645 10430
18480 12320
21525 14350
24675 16450
18
⁄ACH x Total Input
3
communicating through vertical ducts. Provide
minimum free area of 1 in² per 4 [(BTU/
hr)/1,000] of total input rating of all appliances
in enclosure.
Provide minimum free area of 1 in² per 2
[(BTU/HR)/1,000] of total input rating of all
appliances in enclosure.
0.3 0.4
3098
4856
6300
7823
9240
10763
12338
PN 240012787 Rev. C [11/15/2020]
[(BTU/HR)/1,000]
0.5 0.6
2478 2065
3885 3238
5040 4200
6258 5215
7392 6160
8610 7175
9870 8225