NOTE: Refer to Location Requirements and Considerations
for combustion air contaminant restrictions.
The following bullets and diagram describe the restrictions
concerning the appropriate location of vent/flue pipe and com-
bustion air intake pipe (when applicable) terminations. Refer to
Non-Direct Vent (Single Pipe) Piping and Direct Vent (Dual
Pipe) Piping located in this section for specific details on
All terminations (flue and/or intake) must be
located at least 12 inches above ground level or
the anticipated snow level.
Vent terminations (non-direct and direct vent) must
terminate at least 3 feet above any forced air inlet
located within 10 feet.
NOTE: This provision does not apply to the
combustion air intake termination of a direct vent
The vent termination of a non-direct vent application
must terminate at least 4 feet below, 4 feet
horizontally from, or 1 foot above any door,
window, or gravity air inlet into any building.
The vent termination of a direct vent application
must terminate at least 12 inches from any opening
through which flue gases may enter a building (door,
window, or gravity air inlet).
The vent termination of vent pipe run vertically
through a roof must terminate at least 12 inches
above the roof line (or the anticipated snow level)
and be at least 12 inches from any vertical wall
(including any anticipated snow build up).
A vent termination shall not terminate over public
walkways or over an area where condensate or
vapor could create a nuisance or hazard or could
be detrimental to the operation of regulators, relief
valves, or other equipment.
The combustion air intake termination of a direct
vent application should not terminate in an area
which is frequently dusty or dirty.
NOTE: In Canada, the current edition of CAN/CSA B149.1-
15 takes precedence over the preceding termination
Canadian Vent Pipe & Combustion Air Pipe
All installations in Canada must conform to the require-
ments of CAN/CSA B149.1 -15 code. All vent components,
including primer and cement, must be listed to ULC S636.
The certified pipe and fittings should be clearly marked with
the ULC standard "S636". The primer and cement used must
be of the same manufacturer as the vent system. For Royal
Pipe System 636; use GVS-65 Primer (Purple) and GVS-65
PVC Solvent Cement. For IPEX System 636, use PVC/CPVC
Primer, Purple or clear. Use PVC Solvent Cement (Gray).
For Canadian installations, ABS may be used as a combus-
tion air pipe only. ABS is not an approved vent material in
Canada. If ABS is used as a combustion air pipe, it must be
CSA certified. Always follow the manufacturer's instructions
in the use of primer and cement. Do not use primer and
cement around potential sources of ignition. Do not use
primer or cement beyond its expiration date.
The safe operation, as defined by ULC S636, of the vent
system is based on following these installation instructions,
the vent system manufacturer's installation instructions,
and proper use of primer and cement. It is recommended
under this standard, that the vent system be checked
once a year by qualified service personnel. All fire stops
and roof flashings used with this system must be UL listed.
Acceptability under CAN/CSA B149.1-15 is dependent upon
full compliance with all installation instructions. Consult
the authority having jurisdiction (gas inspection authority,
municipal building department, fire department, etc.) be-
fore installation to determine the need to obtain a permit.
*IPEX System 636™ is a trademark of IPEX Inc.
Carefully follow the pipe manufacturers' instructions for cutting,
cleaning, and solvent cementing PVC and/or ABS.
The vent can be run through an existing unused chimney provid-
ed the space between the vent pipe and the chimney is insulated
and closed with a weather-tight, corrosion-resistant flashing.
Standard Furnace Connections
It is the responsibility of the installer to ensure that the piping
connections to the furnace are secure, airtight, and adequately
The vent pipe outlet is sized to accept 2" pipe. Secure vent/
flue pipe directly into the furnace fitting with the appro-
priate glue. Alternately, a small section of 2" pipe may be
glued in the furnace socket and a rubber coupling installed
to allow removal for future service. Combustion Air and
Vent piping should be routed in a manner to avoid contact
with refrigerant lines, metering devices, condensate drain
lines, etc. If necessary, clearances may be increased by
creating an offset using two 45 degree elbows (Figure 8A).
Increased Clearance Configuration