IMC · 2021 International Mechanical Code

§602.1 · General installation

Effective in IMC 2021 · IMC 2024 SE Wisconsin · IMC 2024 NW Indiana.

Plain-English explainer

602.1 says ducts are supported, sealed, and protected against condensate and physical damage, and joints on low-pressure metal ductwork are sealed to a class appropriate for the static. The drafter cites it whenever a permit mentions a tight attic or above-grade run routed through unconditioned space.

Why inspectors flag this

Unsealed or sagging joints are an easy inspector call at rough-in; this rule on the draft lets the contractor re-crimp and tape before the walk-through.

As quoted in the code: Ducts are supported, sealed, and protected against condensate and physical damage; joints on low-pressure metal ductwork are sealed to a class appropriate for the static.

See all codes that cite this trade

Browse the full International Mechanical Code index for one place to read every section the drafter is allowed to quote. See all codes →

See pricing

See every code, every jurisdiction — without the binder.

Trussmark turns job-site photos and voice notes into code-cited permit drafts the inspector can verify on the spot. Pick the plan that fits your shop and we will size the rest with you. Already cited this code in IMC 2021? Drop your email and we'll size the rest of the permit draft for you. See pricing →

See pricing