Thefollowingareasortypesofstructuresmaycontainorhaveex-
posuretothesubstanceslistedbelow.Theinstallationmustbe
evaluatedcarefullyasitmaybenecessarytoprovideoutsideair
forcombustion.
• Commercialbuildings.
• Buildingswithindoorpools.
• Furnacesinstalledinlaundryrooms.
• Furnacesinstalledinhobbyorcraftrooms.
• Furnacesinstallednearchemicalstorageareas.
• Permanentwavesolutionsforhair.
• Chlorinatedwaxesandcleaners.
• Chlorinebasedswimmingpoolchemicals.
• Watersofteningchemicals.
• De-icingsaltsorchemicals.
• Carbontetrach!oride.
• Halogentyperefrigerants.
• Cleaningsolvents(suchasperchloroethylene).
• Printinginks,paintremovers,varnishes,etc.
• Hydrochloricacid.
• SulfuricAcid.
• Solventcementsandglues.
• Antistaticfabricsoftenersforclothesdryers.
• Masonryacidwashingmaterials.
ConfinedSpace Installation
NOTE: A confined space is defined as an area with less than 50
cubic feet per 1,000 BTUH input rating for all gas appliances
installed in the area.
Air OpeningsandConnecting Ducts
1. Total input rating for all gas appliances MUST be considered
when determining free area of openings.
2. Connect ducts or openings directly to outside.
3. When screens are used to cover openings, the openings
MUST be no smaller than 1/4" mesh.
4. The minimum dimension of rectangular air ducts MUST NOT
be less than 3".
5. When sizing grille or louver, use the free area of opening. If
free area is NOT stamped or marked on grill or louver, as-
sume a 20% free area for wood and 60% for metal.
Requirements
1. Provide confined space with sufficient air for proper combus-
tion and ventilation of flue gases using horizontal or vertical
ducts or openings.
2. Figure 6 illustrates how to provide combustion and ventila-
tion air. A minimum of two permanent openings, one inlet and
one outlet, are required.
Outside Air (This is ONLY a guide. Subject to codes of country having jurisdiction.)
ThisinstallationNOTapprovedinCanada
Gas Vent , Gable Vent Gsl.slVe_le Vent
(f)
/3
i iI I _ ITM
| l] Soffit Vent
soffitvent utletAi''f'II
I _ .LL II I Outlet
Inlet -_'"'"1 [::t;I Inlet
Air(f) d"l I I I _11 • Air(2)
VentilatedCrawlSpace Inlet
MinimumOneInletandOneOutletAirSupplyisRequired Air(1}
MaybeinendCombinationShown
InletAirOpeningMustbeWithinf2"(300mm)offloor
OutletAirOpeningMustbeWithin12"(300mm)ofceiling
(1)1SquareInch(6om2)per4000BTUH
(2)1SquareInch(6cm2)per2000BTUH
iFurn_oe
3a_
Outlet
_] Air(2)
Inlet
Air(2)
3.
4.
5.
6.
One opening MUST be within 12" of the floor and the second
opening within 12" of the ceiling.
Size openings and ducts per Table 1.
Horizontal duct openings require 1 square inch of free area
per 2,000 BTUH of combined input for all gas appliances in
area (see Table 1).
Vertical duct openings or openings directly to outside require
1 square inch of free area per 4,000 BTUH for combined input
of all gas appliances in area (see Table 1).
One permanent opening, commencing within 12" of the top of the
enclosure, shall be permitted where the equipment has clear-
ances of at least 1" from the sides and back and 6" from the front
of the appliance. The opening shall directly communicate with the
outdoors or shall communicate through a vertical or horizontal
duct to the outdoors or spaces (crawl or attic) that freely communi-
cate with the outdoors, and shall have a minimum free area of:
• 1 sq. in per 3000 Btu per hr. of the total input rating of all
equipment located in the enclosure, and
• Not less than the sum of the areas of all vent connectors in
the confined space.
_] 441 01260302
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