Valve Inspection and Quality Hold Points

What Are Hold Points?

Hold points (H) and witness points (W) are defined stops in valve manufacturing where a third-party inspector or client representative must be present before work can proceed. They ensure critical quality gates are not bypassed.

Common Hold Points in Valve Manufacturing

• H: Chemical analysis and heat treatment records review before machining

• H: Dimensional inspection after final machining

• H: Shell pressure test witnessed by third party

• H: Seat leakage test with client present

• W: Non-destructive examination (NDE) results review

• W: Coating thickness and holiday test

Inspection Test Plan (ITP)

The ITP is the governing document that lists all inspection activities, the responsible party, the applicable standard, and the hold/witness/review designation. It is agreed between buyer, manufacturer, and inspection agency before production starts.

Third-Party Inspection Agencies

• Bureau Veritas (BV)

• SGS, Intertek, TUV

• Lloyd's Register

• Client-nominated inspection bodies

Documentation at Hold Points

All hold-point records—test reports, certificates, dimensional sheets—become part of the Material Record Book (MRB) delivered with the valve. Missing documentation can delay final acceptance and shipment.