Page 618 - 2018_IRC

FUEL GAS

rial. Any material used to close up such opening shall or gravity air inlet into any building. The bottom of the
be noncombustible. vent terminal shall be located not less than 12 inches
(305 mm) above finished ground level.
G2427.7.8 (503.7.8) Clearances. Minimum clearances
from single-wall metal pipe to combustible material shall 3. The clearances for through-the-wall, direct-vent termi-
be in accordance with Table G2427.10.5. The clearance nals shall be in accordance with Table G2427.8.
from single-wall metal pipe to combustible material shall
be permitted to be reduced where the combustible material 4. Through-the-wall vents for Category II and IV appli-
is protected as specified for vent connectors in Table ances and noncategorized condensing appliances shall
G2409.2. not terminate over public walkways or over an area
where condensate or vapor could create a nuisance or
G2427.7.9 (503.7.9) Size of single-wall metal pipe. A
venting system constructed of single-wall metal pipe shall hazard or could be detrimental to the operation of regu-
lators, relief valves or other equipment. Where local
be sized in accordance with one of the following methods experience indicates that condensate is a problem with
and the appliance manufacturer’s instructions: Category I and III appliances, this provision shall also
1. For a draft-hood-equipped appliance, in accordance apply. Drains for condensate shall be installed in accor-
with Section G2428. dance with the appliance and vent manufacturer’s
instructions.
2. For a venting system for a single appliance with a
draft hood, the areas of the connector and the pipe 5. Vent systems for Category IV appliances that terminate
each shall be not less than the area of the appliance through an outside wall of a building and discharge flue
flue collar or draft hood outlet, whichever is gases perpendicular to the adjacent wall shall be
smaller. The vent area shall be not greater than located not less than 10 feet (3048 mm) horizontally
seven times the draft hood outlet area. from an operable opening in an adjacent building. This
requirement shall not apply to vent terminals that are 2
3. Other approved engineering methods.
feet (607 mm) or more above or 25 feet (7620 mm) or
G2427.7.10 (503.7.10) Pipe geometry. Any shaped sin- more below operable openings.
gle-wall metal pipe shall be permitted to be used, provided
that its equivalent effective area is equal to the effective TABLE G2427.8 (503.8)
THROUGH-THE-WALL,
area of the round pipe for which it is substituted, and pro- DIRECT-VENT TERMINATION CLEARANCES
vided that the minimum internal dimension of the pipe is THROUGH-THE-WALL VENT
not less than 2 inches (51 mm). DIRECT-VENT TERMINAL CLEARANCE FROM ANY
APPLIANCE INPUT RATING AIR OPENING INTO THE BUILDING
G2427.7.11 (503.7.11) Termination capacity. The vent (Btu/hr) (inches)
cap or a roof assembly shall have a venting capacity of not < 10,000 6
less than that of the pipe to which it is attached.
≥ 10,000 ≤ 50,000 9
G2427.7.12 (503.7.12) Support of single-wall metal > 50,000 ≤ 150,000 12
pipe. All portions of single-wall metal pipe shall be sup-
ported for the design and weight of the material employed. In accordance with the appliance
manufacturer’s instructions and not
> 150,000
G2427.7.13 (503.7.13) Marking. Single-wall metal pipe less than the clearances specified in
shall comply with the marking provisions of Section Section G2427.8, Item 2
G2427.6.10.
For SI: 1 inch = 25.4 mm, 1 Btu/hr = 0.2931 W.
G2427.8 (503.8) Venting system termination location. The G2427.9 (503.9) Condensation drainage. Provisions shall
location of venting system terminations shall comply with the be made to collect and dispose of condensate from venting
following (see Appendix C): systems serving Category II and IV appliances and noncate-
1. A mechanical draft venting system shall terminate not gorized condensing appliances in accordance with Section
less than 3 feet (914 mm) above any forced-air inlet G2427.8, Item 4. Where local experience indicates that con-
located within 10 feet (3048 mm). densation is a problem, provisions shall be made to drain off
and dispose of condensate from venting systems serving Cat-
Exceptions: egory I and III appliances in accordance with Section
G2427.8, Item 4.
1. This provision shall not apply to the combus-
tion air intake of a direct-vent appliance. G2427.10 (503.10) Vent connectors for Category I appli-
2. This provision shall not apply to the separa- ances. Vent connectors for Category I appliances shall com-
tion of the integral outdoor air inlet and flue ply with Sections G2427.10.1 through G2427.10.13.
gas discharge of listed outdoor appliances.
G2427.10.1 (503.10.1) Where required. A vent connec-
2. A mechanical draft venting system, excluding direct- tor shall be used to connect an appliance to a gas vent,
vent appliances, shall terminate not less than 4 feet chimney or single-wall metal pipe, except where the gas
(1219 mm) below, 4 feet (1219 mm) horizontally from, vent, chimney or single-wall metal pipe is directly con-
or 1 foot (305 mm) above any door, operable window nected to the appliance.

2018 INTERNATIONAL RESIDENTIAL CODE ® 593
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