6
I-RIH (05-21) 131793-A
GENERAL INFORMATION—CONTINUED
Ventilation Requirements
⚠ DANGER ⚠
Insufficient ventilation may result in health problems, carbon monoxide poisoning, or death. Always
vent enclosed spaces and buildings in accordance with national, state, provincial, and local codes.
•
These heaters are the unvented type . Generated products of combustion are released into the space being
heated . Sufficient ventilation of fresh air is required to provide adequate air for efficient combustion and to dilute
and remove the products of combustion .
• In the U.S.,
the minimum intake and exhaust air openings shall provide for not less than 4 CFM per 1,000 BTUh
(0 .38m3 a minute per kW) . In the U .S ., this may be accomplished by either gravity or mechanical means . Both
exhaust fans and inlet air openings are required in tight buildings . Exhaust openings for removing flue products
shall be above the level of the heater (ANSI Z223 .1/NFPA 54, section 10 .18,
Infrared Heaters
) .
•
Air for combustion, ventilation, and dilution of flue gases shall be obtained by application of one of several methods
described in the National Fuel Gas Code, ANSI Z223 .1/NFPA 54, section 9 .3,
Air for Combustion and Ventilation
.
•
The ventilation technical information outlined in the current ASHRAE Handbooks should be observed when
locating vents . When mechanical means are provided to supply and exhaust, a positive interlock with the heater
thermostat must be provided by the installer so that the heater cannot operate unless the supply and exhaust
system is operating .
•
Mechanical exhaust fans are typically located at high points of the building . For flat roof areas, a series of small
exhausters should be distributed over the roof areas and interlocked with various heating zones . Local codes
may permit the use of humidistat control to remove water vapor and products of combustion . Humidistat settings
will typically be in the 40% to 55% relative humidity range .
•
Fresh air intake openings are typically located high on the building sidewalls at or above the level of the heaters .
One square inch of net free inlet area per 1,000 BTUh (22cm2 per kW) is required . Multiple inlets, well-distributed,
should be used and should direct air upward to prevent drafts at floor level . Inlets are typically limited to 1–2
square feet (900–1,800 cm
2
) in size . Total area required can be computed by dividing exhaust CFM by 500 feet
per minute . (cubic meters per minute ÷ 152 meters per minute) .
• In Canada,
the Natural Gas and Propane Installation Code CAN/CSA B149 .1 (latest edition) requires the use of
mechanical ventilation . The heater shall be provided with mechanical ventilation for combustion and ventilation
air as follows:
•
located so that products of combustion from each heater are effectively removed outdoors
•
with ventilation volume of at least 3 CFM per 1,000 BTUh (0 .29m3 a minute per kW) for natural gas or 4 CFM
per 1,000 BTUh (0 .38m3 a minute per kW) for LP/propane
•
sufficient to maintain the carbon dioxide level at <5,000 ppm measured 6 feet (2 meters) above the work area
Dimensions
C
A
13"
(330mm)
B
23-23/32"
(603mm)
8-1/2"
(216mm)
Figure 1. Unit Dimensions (Refer to
)
