Distance/Clearance for Vent Terminals
(For reference only. Refer to the latest edition of
local/national codes for up to date distances)
Structure
Air inlet supply
Door, window, gravity
air inlet, or any building
opening
Electric meter, gas meter,
gas regulator, and relief
equipment ¹
Adjacent public walkways
Grade (ground level)
Snow line
VERTICAL VENTING
WARNING: For Category I venting (vertical), if the horizontal
length of the vent pipe exceeds the allowable horizontal
length in the latest edition of local codes, or in the absence
of local codes the latest edition of The National Fuel Gas
Code, NFPA 54/ANSI Z223.1 in the USA or Natural Gas and
Propane Installation Code CSA B149.1 in Canada, then the
heater is to be installed as a Category III horizontal vented
appliance as described in the "Horizontal Venting" section of
this manual.
1.
Category I vertical vent pipe, refer to local/national codes for:
a.
Vent pipe size, material, and thickness
ii.
Single wall vent pipe requirements
iii.
Double wall vent pipe requirements
b.
Maximum allowable horizontal length of vent pipe in the
system
c.
Distances to roof lines for varying roof pitches.
d.
Distances to other buildings, structures, or walls.
2.
Vent connectors serving Category I appliances shall not be
connected into any portion of mechanical draft systems operating
under positive pressure.
3.
Refer to Figures 4, 5, 6 and 7 for vertical venting
recommendations.
4.
The vent pipe must have a listed vent terminal/cap securely
fastened to it. The size of the required terminal is listed in
Table 5.
5.
The inlet air pipe used on separated combustion models must
have a listed vent terminal/cap. The size of the required terminal
is listed in Table 5.
6.
The vent pipe must be a minimum of 5 vertical feet in height. This
means there should be a minimum of a 5' vertical piece of vent
pipe between the appliance and the listed vent cap. Refer to local
and national codes for the maximum horizontal run of a vertical
vent system.
7.
The vent cap must be at least 12" above the maximum snow load.
Consider snow drifts that may occur.
TABLE 6
Minimum Distance/
Clearance for Vent Terminal
Location
3' (0.91m) above or 10' (3m)
horizontally
4' (1.22m) horizontal
and below
1' (0.3m) above
U.S.: 4' (1.22m) horizontal Cana-
da: 6' (1.83m) horizontal
7' (2.13m) all directions
1' (0.3m) above
1' (0.3m) above (consider drifts)
Compact Unit Heater
8.
The heat from the flue products in the heater can cause damage
to sloped and flat roof materials. Verify the temperature rating of
the roof material and confirm that the hot flue products from the
vent pipe will not cause damage to the roof material.
9.
When installing a two-pipe system vertically (Separated
Combustion with vent pipe and inlet pipe), the two pipes must
both terminate vertically and both pipes should be within the
same general area.
10. Both the vent pipe and inlet pipe should have a tee and drip/
sediment leg with a clean out cap to clean out any debris that
may get into the pipes.
11. The separated combustion air inlet pipe seams must be airtight,
so all air comes from the outdoors. The inlet pipe can be sealed
with a material suitable for the environment where the inlet pipe
is installed. Possible materials include duct tape, caulk, or silicone
sealant.
12. Condensation may form as cold air moves through the inlet pipe.
Protect equipment and materials from dripping condensation.
The inlet pipe may need to be wrapped in insulation to avoid
condensation.
13. The vent pipe must terminate at least 12" (30.5 cm) above and
12" (30.5 cm) horizontally from the air inlet pipe on Separated
Combustion Heaters.
14. Refer to Figures 4 - 7; Table 6 and local/national codes for
distances to buildings, walls, sloped roofs, and other objects.
Vertical Category I Vent System - Vent Pipe Only, Sloped Roof
Vertical Category I Vent System - Vent Pipe and Air
Inlet Pipe, Sloped Roof
8
Operating Instructions and Owner's Manual
FIGURE 4
FIGURE 5