IMC · 2024 International Mechanical Code

§603.4 · Supply ducts in unconditioned space sized to R-6 (flexible) / R-8 (rigid) for NW Indiana duct insulation; return-side insulation remains R-6.

Local amendment on §603.4 for the IMC 2024 NW Indiana jurisdiction.

Plain-English explainer

The NW Indiana amendment to §603.4 keeps the IMC R-6 flexible / R-8 rigid supply-duct R-values. The drafter cites it for permits pulled in NW Indiana — the local authority's wording matches the IMC without tightening.

Why inspectors flag this

A NW Indiana crew wiring the supply run at the IMC R-6 / R-8 rate passes the rough-in; the drafter surfaces the rule so the wrap matches the local amendment.

As quoted in the code: See §603.4 amendment.

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