Static field route #19078

What do I do when flex duct kinks right off a plenum start collar?

Flex Duct Connections & Supports✅ STANDARD FIELD CORRECTIONV190 answer-gap expansion

📖 Verified core answer

Flex cannot make a sharp unsupported turn off a collar without choking. Use a smoother path, hard elbow/boot where needed, and support the flex so the core stays open.

Open in Field Rescue Open category

Field verification checklist

Look at the flex core shape, not just the outer jacket.
Check if a light, grid, pipe, or wire is forcing the bend too tight.
Verify the start collar is secure and not tearing the plenum.
Use rigid elbow/boot or supported sweeping bend if approved.
Recheck airflow/noise after the kink is removed.

Ask foreman

The flex off this plenum collar is kinked tight around [obstacle]. I checked the core and support. Do you want a hard elbow/boot added or the flex rerouted for a smoother bend?

Text to foreman

Route options

AMake the field correction only if it is within your assignment and the approved method.

BHold and document the condition if the fix affects airflow, access, life safety, pressure class, rated assemblies, equipment, or another trade.

CBring the foreman/detailer the location, what you checked, and what decision you need before cover, startup, or rework.

Do not do this

Do not pull flex tight around an obstacle and leave the core flattened at the collar.

Why this matters

A kinked flex start can starve a diffuser, create noise, and waste time during TAB.

Verification basis

Approved drawings/specs, project coordination drawings, manufacturer instructions/submittals, shop standards, foreman/detailer direction, employer policy, and AHJ/code requirements.