Static field route #19073

What do I do when spiral pipe starts bulging or unzipping at the lockseam?

Spiral, Round & Oval Duct Install🟨 CHECK FIRSTV190 answer-gap expansion

📖 Verified core answer

Bulging or unzipping spiral pipe means the pipe/joint is not handling the pressure or system condition. Stop the test/startup and verify gauge, pressure class, joint, and replacement/reinforcement options.

Open in Field Rescue Open category

Field verification checklist

Stop or secure the system/test if the seam is actively opening.
Confirm duct diameter, pressure class, pipe type, gauge/material, and shop markings if available.
Check if pressure spiked due to closed dampers, blocked outlets, VFD ramp, or wrong test setup.
Inspect hangers and joints near the bulged section.
Ask before adding any sleeve or clamp as a permanent fix.

Ask foreman

The spiral lockseam is bulging/opening at [location] during [test/startup]. I checked pressure condition and pipe markings. Do you want this section replaced with rated pipe or held for an approved repair detail?

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 keep pressurizing spiral duct that is unzipping or bulging at the seam.

Why this matters

A failing spiral seam can dump air, fail testing, damage nearby work, or become unsafe if the pressure condition continues.

Verification basis

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