Gas Furnaces
VENTED APPLIANCE CATEGORIES
Category I. An appliance that operates with a no positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent
Category II. An appliance that operates with a no positive vent static pressure and with a vent gas temperature that is capable of causing excessive condensate production in the vent
Category III. An appliance that operates with positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent
Category IV. An appliance that operates with positive vent static pressure, with a vent gas temperature that is capable of causing excessive condensate production in the vent
Gas Line Requirements:
Appliances
G2419.4 (408.4)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Sediment trap
SECTION G2420Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â SHUTOFF VALVES
APPLIANCE GAS CONNECTIONS
G2422.1Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Connecting appliances
G2422.1.1Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Protection from damage
G2422.1.2.3Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Prohibited locations and penetrations
HVAC General
M1401.1 | Installation | |
M1401.2 | Access | |
M1401.3 | Equipment and appliance sizing | |
M1401.4 | Exterior installation | |
M1401.5 | Flood Hazards | |
SECTION M1307
Appliance Installation General
M1305.1 | Clearance and access requirements | |
M1305.1.1 M1402.2 | Furnaces and air handler clearance | |
M1305.1.2 | Appliances in rooms | |
M1305.1.3 | Appliances in attics | |
M1305.1.4 | Appliances under floors | |
M1305.1.3.1 | Lighting requirements at appliance | |
M1305.1.4.1 | Ground clearances | |
M1307.2 | Appliance anchoring | |
M1306.1 | Clearance from combustibles | |
M1307.3 | Elevation from ignition source | |
M1307.3.1 | Protection from impact |
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Return Air Requirements
IMC 601.5 Prohibits return air within 10 ft from combustion appliances.
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Combustion Air
M1701.1 | Scope | |
M1701.2 | Opening locations |
Combustion Air and venting and dilution air requirements
Sections G2406 -- G2407 -- G2408
Prohibited Locations inside appliance locations | ||
Combustion air | ||
Appliance combustion air | ||
Appliance location | ||
Draft hood/regulator location | ||
Make up air required | ||
Indoor combustion air | ||
Outdoor combustion air | ||
Elevation of ignition source | ||
Installation in garages | ||
Clearance from grade | ||
Clearance from combustibles | ||
Clearance reduction allowances |
Gas furnace venting requirements
CO Vent Requirements:
Unless specified, manufacturer’s instructions should be followed. Venting code references are listed below.
Code Reference | Description | Â |
General requirements | ||
Installation Requirements | ||
Required connectors | ||
Shielding from insulation | ||
Protection against damage | ||
 | ||
SECTION G2427 | Venting of appliances | |
Above air handling spaces | ||
G2427.4 | Vent type required for appliance category (I.E. Type 1 or Type 4) | |
G2427.4.1 | Plastic Vent Pipes | |
Chimney roof terminations | ||
 | ||
Gas vent roof terminations | ||
G2427.6.7 | Exterior wall terminations | |
G2427.6.5 | Minimum height requirements | |
G2427.7.1-13 | Single wall vent pipe | |
Vent connector requirements | ||
Draft hoods and controls | ||
Direct vent and integral vent systems |
