Inspection and Test Plans (ITP) for Pipe Fitting Procurement: Hold Points, Witness Points, and Review Points Explained
An Inspection and Test Plan (ITP) is a document that defines, for each stage of pipe fitting manufacture and inspection, what activity is performed, what standard or acceptance criterion applies, what records are generated, and what level of oversight is required from the manufacturer, the client, and any third-party inspection agency (TPI). The ITP is agreed between buyer and seller at order placement and forms part of the quality management requirements of the purchase order. Understanding the different levels of inspection point is essential for both buyers specifying what oversight they require and suppliers planning their production and inspection schedule.
Hold Points (H)
A Hold Point is the most stringent level of inspection point. At a Hold Point, production or the subsequent operation cannot proceed until the specified party (client, TPI, or both) has been notified, has attended, and has signed off on the activity or result. The key characteristic of a Hold Point is that it is absolute — the manufacturer has no authority to proceed without the required party being present and approving. Hold Points are appropriate for: final dimensional inspection before release; pressure testing (particularly where code or PED requires Notified Body witness); heat treatment (where the time-temperature chart must be witnessed and signed); final NDE after PWHT (particularly for P91/P22 fittings); and release for shipment. If the client or TPI fails to attend a scheduled Hold Point, the manufacturer must wait — production cannot progress. The practical implication is that Hold Points must be notified in advance with adequate lead time (typically 3–5 working days minimum) to allow the inspector to travel to the manufacturing facility. Excessive Hold Points impose significant schedule risk — each Hold Point is a potential delay if the inspector is not available promptly.
Witness Points (W)
A Witness Point requires that the specified party is notified in advance and has the opportunity to attend and witness the activity, but the manufacturer may proceed with the activity if the party does not attend after receiving the required notice. The notice period is specified in the ITP (typically 3–5 working days). If the client or TPI acknowledges the notification and confirms they will not attend, the activity can proceed without their presence. Witness Points are used for activities where client oversight adds significant value but where the risk of missing the activity is acceptable — for example: material receipt inspection (the client or TPI may wish to verify heat number and visual condition but, if they cannot attend, the manufacturer's documented incoming inspection is acceptable); in-process dimensional checks; and radiographic film review (the client may wish to review the RT film but, if unable, the manufacturer's Level III interpretation is accepted). The distinction between Hold and Witness is the right of the manufacturer to proceed without the party's presence — this is the key clause to negotiate carefully in the ITP.
Review Points (R)
A Review Point (sometimes called a Document Review point or simply R-point) requires that specified records or documents are submitted to the relevant party for review and approval before the next stage of activity can proceed — but the party does not need to be physically present at the manufacturing facility. Review Points are used for: approval of heat treatment procedures (PWHT procedure to be reviewed and approved before production PWHT commences); review of NDE procedures (RT, UT, MT procedures to be approved before NDE personnel mobilise); review of welder/welding operator qualification records; and review of final documentation (data books, material dossiers, release notes) before shipment is approved. Review Points typically have a defined response time — the client or TPI has a specified number of working days (commonly 5–10 days) to review and respond. If no response is received within that period, the activity is deemed approved and production proceeds.
Structuring an ITP for CrMo Alloy Steel Fittings
For P91 or P22 pipe fittings in critical high-temperature service, a typical ITP structure might include: material receipt inspection — R (certificate review) or W (physical inspection of markings); forming and dimensional inspection — W (manufacturer notifies, TPI may attend); PWHT procedure review — R (client approves PWHT procedure before production); production PWHT — W (TPI may witness, review time-temperature chart); post-PWHT hardness testing — W or H (depending on project criticality); NDE (RT/UT/MT) — W (TPI may witness NDE activities); final dimensional and visual inspection — H (TPI must be present); hydrostatic test — H (TPI must witness, Notified Body if PED applies); PMI — W (TPI may witness); data book assembly and review — R (client reviews documentation before release); and release for shipment — H (TPI signs release note). The specific mix of H, W, and R points for a given project should be proportional to the service criticality and the supplier's track record — over-specifying Hold Points on a well-established supplier with a strong quality record adds cost and schedule risk without adding proportionate quality assurance.