Page 637 - 2018_IRC

FUEL GAS

SECTION G2442 (618) hood in the same room or space or the
FORCED-AIR WARM-AIR FURNACES combustion chamber of any atmo-
spheric burner appliance in the same
G2442.1 (618.1) General. Forced-air warm-air furnaces
shall be tested in accordance with ANSI Z21.47/CSA 2.3 or room or space.
UL 795 and shall be installed in accordance with the manu- 3. Rooms or spaces containing solid fuel-burning
facturer’s instructions. appliances, provided that return-air inlets are

G2442.2 (618.2) Dampers. Volume dampers shall not be located not less than 10 feet (3048 mm) from
placed in the air inlet to a furnace in a manner that will reduce the firebox of such appliances.
the required air to the furnace. 6. A closet, bathroom, toilet room, kitchen, garage, boiler
G2442.3 (618.3) Prohibited sources. Outdoor or return air room, furnace room or unconditioned attic.
for forced-air heating and cooling systems shall not be taken Exceptions:
from the following locations:
1. Where return air intakes are located not less
1. Closer than 10 feet (3048 mm) from an appliance vent than 10 feet (3048 mm) from cooking appli-
outlet, a vent opening from a plumbing drainage system ances and serve only the kitchen area, taking
or the discharge outlet of an exhaust fan, unless the out- return air from a kitchen area shall not be pro-
let is 3 feet (914 mm) above the outside air inlet. hibited.
2. Where there is the presence of objectionable odors, 2. Dedicated forced-air systems serving only a
fumes or flammable vapors; or where located less than garage shall not be prohibited from obtaining
10 feet (3048 mm) above the surface of any abutting return air from the garage.
public way or driveway; or where located at grade level
by a sidewalk, street, alley or driveway. 7. A crawl space by means of direct connection to the
return side of a forced-air system. Transfer openings in
3. A hazardous or insanitary location or a refrigeration the crawl space enclosure shall not be prohibited.
machinery room as defined in the International
Mechanical Code. G2442.4 (618.4) Screen. Required outdoor air inlets shall be
covered with a screen having / -inch (6.4 mm) openings.
1
4. A room or space, the volume of which is less than 25 4
percent of the entire volume served by such system. G2442.5 (618.5) Return-air limitation. Return air from one
Where connected by a permanent opening having an dwelling unit shall not be discharged into another dwelling unit.
area sized in accordance with this code, adjoining G2442.6 (618.6) Furnace plenums and air ducts. Where a
rooms or spaces shall be considered to be a single room furnace is installed so that supply ducts carry air circulated by
or space for the purpose of determining the volume of the furnace to areas outside of the space containing the fur-
such rooms or spaces. nace, the return air shall be handled by a duct(s) sealed to the
Exception: The minimum volume requirement shall furnace casing and terminating outside of the space contain-
not apply where the amount of return air taken from ing the furnace.
a room or space is less than or equal to the amount
of supply air delivered to such room or space.
SECTION G2443 (619)
5. A room or space containing an appliance where such a CONVERSION BURNERS
room or space serves as the sole source of return air.
G2443.1 (619.1) Conversion burners. The installation of
Exception: This shall not apply where: conversion burners shall conform to ANSI Z21.8.
1. The appliance is a direct-vent appliance or an
appliance not requiring a vent in accordance
with Section G2425.8. SECTION G2444 (620)
2. The room or space complies with the follow- UNIT HEATERS
ing requirements: G2444.1 (620.1) General. Unit heaters shall be tested in
accordance with ANSI Z83.8/CSA 2.6 and shall be installed
2.1. The return air shall be taken from a
room or space having a volume in accordance with the manufacturer’s instructions.
exceeding 1 cubic foot for each 10 G2444.2 (620.2) Support. Suspended-type unit heaters shall
Btu/h (9.6 L/W) of combined input rat- be supported by elements that are designed and constructed to
ing of all fuel-burning appliances accommodate the weight and dynamic loads. Hangers and
therein. brackets shall be of noncombustible material.
2.2. The volume of supply air discharged G2444.3 (620.3) Ductwork. Ducts shall not be connected to
back into the same space shall be a unit heater unless the heater is listed for such installation.
approximately equal to the volume of
return air taken from the space. G2444.4 (620.4) Clearance. Suspended-type unit heaters
shall be installed with clearances to combustible materials of
2.3. Return-air inlets shall not be located not less than 18 inches (457 mm) at the sides, 12 inches (305
within 10 feet (3048 mm) of a draft mm) at the bottom and 6 inches (152 mm) above the top where

612 2018 INTERNATIONAL RESIDENTIAL CODE ®
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