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LAARS HEATING SYSTEMS
2L-4. Side Wall Vent Terminal
The side wall vent hood must be used when the
heater is vented through a side wall. It provides a
means of installing vent piping through the building
wall, and must be located in accordance with ANSI
Z223.1/NFPA 54 and applicable local codes. In
Canada the installation must be in accordance with
CAN/CGA B149.1 or .2 and local applicable codes
(see Figure 10). Consider the following when
installing the terminal:
1.
Locate the vent terminal so that it will not be
damaged by pedestrians and other traffic, and so
the discharge is not objectionable. The National
Fuel Gas Code requires a through-wall vent
terminal be at least 7 feet (2.1m) above grade if
located at a public walkway.
2.
Locate the vent terminal so that vent gases
cannot be drawn into air conditioning system
inlets. The National Fuel Gas Code requires that
it be at least 6 feet (1.8m) above any such inlet
that is within 10 feet (3.0m).
3.
Locate the vent terminal so that vent gases
cannot enter the building through doors,
windows, gravity inlets or other openings. The
National Fuel Gas Code requires that it be
located at least 4 feet (1.2m) below, 4 feet
(1.2m) horizontally from, or 3 feet (0.9m) above
such openings.
4.
Locate the vent terminal so that it cannot be
blocked by snow. The National Fuel Gas code
requires that it be at least 12 inches (305mm)
above grade, but the installer may determine it
should be higher depending on local conditions.
5.
Locate the terminal so the vent exhaust does not
settle on building surfaces and other nearby
objects. Vent products may damage such
surfaces or objects. But the actual construction
of the vent terminal and the flow of vent
products must not be altered.
6.
Locate the terminal at least 6 feet (1.8m)
horizontally from any gas or electric metering,
regulating, or relief equipment, or building
opening.
2M. Air for Combustion and Ventilation
The boiler requires air for combustion and the
space around the boiler requires ventilation.
Combustion air can be provided by standard practices
as specified in the installation codes (ANSI Z223.1/
NFPA 54, in Canada, CAN/CGA B149.1 or .2 and
local applicable codes), or ducted directly to the
boiler. Ventilation air must be provided in either case.
Figure 10. Building Exterior.
Dimensions shown in feet (m).
Vent Hood
7 (2.1) Minimum
Above Public
Walkway
Vent Hood
Vent Hood
1 (0.3) Above Grade
4 (1.2)
Minimum
Vent Hood Must Be
Mounted 4 (1.2)
Minimum Below Windows
3 (0.9m) Minimum
Vent Hood
4 (1.2)
Minimum
6 (1.8) Above Any
Outside Air Intake
Within 10 (3.0)
Vent
Hood
