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Apprentice Q&A · #324

Why is air leaking from the spiral lockseam during a pressure test?

3rd YearYELLOW · Check FirstSpiral Pressure Testing

Short answer

Do not hammer the spiral seam flat. Clean, seal, and wrap/repair it with the approved pressure-class method or replace defective pipe.

Field answer

A whistle from the factory spiral lock can mean a forming defect, damaged seam, oil-contaminated seal area, or pressure-class mismatch.

Find the exact leak, clean the seam, use approved sealant/wrap for that pressure class, and replace the section if the lockseam is mechanically open or failing.

What to check first

Do not do this

Do not smash a spiral seam with a hammer to “tighten” it.

Why it matters

Factory seam leaks can fail pressure testing and become hidden energy/noise problems after ceilings close.

Ask foreman

The spiral lockseam at [location] is whistling during pressure test. I located the seam leak and checked for damage. Do you want approved seam sealing or replacement of the section?

Text this wording

Related Field Rescue route

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Final direction belongs to the foreman, approved drawings/specs, manufacturer instructions, pressure/material schedule, employer policy, and AHJ/code requirements.