TinnerFlow logoTinnerFlow™
Flex Duct, Boots, Collars & Grilles

Flex Listing And Where It's Allowed

Using non-listed/too-long flex where restricted

Red / Stop And Verify2ndBatch 5

What This Helps With

Using non-listed/too-long flex where restricted

Apprentice words: flex allowed

Trade terms: UL 181 listing, class 0/1, plenum rated, length limits in rated areas

Check First

Listing marking and where code/spec allows flex

What Not To Do

Use flex where code prohibits it

What can go wrong: Running flex through rated barriers

Better Foreman Question

Is flex allowed here per code/spec, and what listing?

Open In Ask Foreman

Verify With

Reference type: IMC

Source to verify: IMC; NFPA 90A; UL 181; spec; AHJ

Safe wording: Flex use depends on code, project specs, listing, and local AHJ. TinnerFlow can teach what to check, not override the spec.

Search Related Field ChecksOpen Field ReferencesAsk Foreman