Key takeaways
- An Inspection and Test Plan (ITP) lists every inspection and test for a welded product, in sequence, with the reference, acceptance criteria and record for each.
- It defines who does what: the manufacturer, the client and the third-party inspector, through hold, witness, review and surveillance points.
- A good welding ITP covers three stages: before, during and after welding, plus final documentation.
- Agree the ITP before production starts; most disputes at handover come from an unclear or missing ITP.
The welding Inspection and Test Plan (ITP) is the document that turns a specification into daily checks. It tells the workshop what to inspect and when, tells the client where they want to be present, and tells everyone which record proves that each step was done. This guide explains what a welding ITP contains, how inspection points work, and gives a practical checklist you can use on your next project.
What is an ITP?
An ITP is a table that follows the production sequence of a welded item and lists, for each activity: what is checked, which procedure or standard applies, the acceptance criteria, how often it is checked, who is involved, and which record is produced. It is usually prepared by the manufacturer, reviewed by the client and the third-party inspector, and approved before production starts. Our technical consultancy team regularly supports clients in drafting an accurate ITP.
Hold, witness, review and surveillance points
| Code | Point | What it means |
|---|---|---|
| H | Hold point | Work must stop until the named party has inspected and released it. Used for critical steps, such as procedure qualification tests or final pressure tests. |
| W | Witness point | The named party is notified and may attend. If they do not attend after proper notice, work can continue. |
| R | Review point | The named party reviews documents or records, such as certificates or NDT reports, without attending the activity. |
| S | Surveillance | Random monitoring of an ongoing activity, such as welding parameters, at the inspector’s discretion. |
Each party gets its own column: manufacturer, client and third-party inspector. Agree the notice period for hold and witness points in advance, typically 24 to 48 hours, and how notifications are sent.
Welding ITP checklist
Before welding
- Review of drawings, specification and applicable standards.
- WPSs and supporting WPQRs approved for every joint type.
- Welder and operator qualifications valid for the work.
- Material certificates (for example to EN 10204 3.1) checked against the order, with identification and traceability.
- Consumables approved, with certificates and storage and drying conditions.
- Equipment calibration and validation, including welding machines and inspection instruments.
- NDT procedures approved and personnel certified to ISO 9712.
During welding
- Fit-up and joint preparation: bevel angle, root gap, alignment and cleanliness.
- Preheat and interpass temperature.
- Welding parameters and heat input against the WPS.
- Root inspection and back-gouging where required.
- Interpass cleaning and visual checks.
After welding
- Visual testing of all welds to ISO 17637 and the specified quality level, for example ISO 5817 level B or C.
- NDT by method and extent, for example 10% UT or 100% PAUT, with the acceptance standard.
- Post-weld heat treatment records, where required.
- Dimensional inspection.
- Repairs, re-inspection and non-conformity reports.
- Pressure or leak tests, where applicable.
Final documentation
- Weld map with weld numbers, welders, WPSs and NDT results.
- Material and consumable certificates, calibration records and personnel certificates.
- Signed release note or certificate of conformity.
Practical tip: number every weld on the drawings from the start and use the same number in the ITP records, NDT reports and weld map. Traceability then builds itself as the job progresses.
Common ITP mistakes
- Acceptance criteria written as “as per code” instead of the exact standard and level.
- No NDT extent defined, so every weld becomes a discussion.
- Too many hold points that stop production without adding value.
- No column for the record, so nobody knows what proves that the check was done.
- The ITP revised on site without the client’s approval.
For the flaws your ITP should target, see 10 common weld defects. The inspection activities themselves are covered by our inspection and quality control service.
Our welding engineers and QC inspectors prepare ITPs that match your specification and can be followed on site, then carry out the inspections.
Frequently asked questions
Who prepares the ITP?
Usually the manufacturer or contractor prepares the ITP. The client and the third-party inspector review it and add their inspection points before it is approved.
What is the difference between a hold point and a witness point?
At a hold point work must stop until the named party releases it. At a witness point the party is invited, but work may continue if they do not attend after proper notice.
Is an ITP the same as a quality plan?
No. A quality plan describes how quality is managed on a project. The ITP is the detailed schedule of inspections and tests, and it is often an attachment to the quality plan.
