IFGC 304
What it means on the job
Gas furnaces in confined spaces require combustion air openings — one high and one low — to ensure adequate air for safe combustion. Without it, the furnace can produce CO.
Tested in 1 CraftIQ puzzle
- whats-wrongResidential Furnace Setup
Related IFGC sections
IFGC 404.11 (Protection against corrosion)
Field-applied polyethylene tape is not an approved corrosion-protection system for underground steel gas pipe. Per IFGC 404.11, steel IS permitted underground only when it has a factory-applied, electrically insulating coating AND a cathodic protection system that is monitored and maintained (zinc galvanizing is not recognized as adequate). This install has neither, so it fails — the problem is the missing coating/cathodic protection, not the use of steel itself. The common alternative is PE (polyethylene) plastic, with the steel-to-PE transition (anodeless riser) made before the pipe enters the building, since PE is not permitted inside structures. Note: fuel-gas piping is governed by the IFGC, not the IPC.
IFGC 404.3
Gas piping must not be installed in or through any air duct, clothes chute, chimney, vent, dumbwaiter, or elevator shaft. A leak inside a duct would distribute gas throughout the building.
IFGC 408.4
Gas piping to equipment must have a sediment trap (drip leg) to catch moisture and debris before it enters the gas valve. Prevents valve damage and unsafe operation.
IFGC 408.4 / IPC 1212.7
A sediment trap (drip leg) must be installed as close as practical to the appliance inlet and ahead of the gas valve. It captures moisture and debris that could damage the gas valve.
IFGC 503.6.5
Single-wall vent connectors must slope upward at least 1/4" per foot toward the chimney or vent terminal. Downward slope traps condensate and prevents proper draft.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.