What is a welding inspection test plan (ITP)?

An ITP is a structured document that identifies every inspection and test activity in a fabrication sequence, specifies who performs it, and designates whether each activity is a hold point (work cannot proceed until sign-off), a witness point (notification required but work can proceed if inspector is not present), or a review point (document review only). It goes beyond a general QC plan by tying each activity to a specific stage in production.

Is an ITP required by AWS D1.1?

AWS D1.1 does not mandate the use of a document called an ITP by that name. The standard defines inspection requirements (visual, NDE, dimensional) and defines who may perform them. However, many owner specifications, AISC certification programs, and contract requirements mandate that fabricators produce an ITP as part of the quality management plan. On government, infrastructure, or heavy industrial projects, an ITP is almost always required.

What is the difference between a hold point and a witness point?

A hold point is a mandatory stop—the fabrication sequence cannot advance until the designated inspector reviews and signs off on that stage. A witness point requires that the inspector be notified in advance, but if the inspector waives attendance or is unavailable, work may proceed after the notification window. Hold points are used for critical or irreversible steps; witness points for important but less irreversible ones.

Who signs off on an ITP for structural steel fabrication?

Typically three parties are involved: the fabricator's own QC inspector (which may be an AWS CWI), the contractor's QC representative, and the owner's inspection firm or third-party engineer of record (EOR). Which party signs which hold points depends on the contract. The EOR or owner representative typically holds sign-off authority on the final weld acceptance and NDE review; the fabricator's CWI handles in-process checks.

Welding Inspection Test Plans (ITP) for Structural Fab

What a welding ITP is, how it differs from a QC plan, what hold and witness points look like in practice, and how it links to your AWS D1.1 WPS documentation.

On any structural project large enough to involve an owner's inspection representative, a government agency, or an AISC-certified fabricator, you will encounter the inspection test plan. The ITP is not an AWS D1.1 document—the code does not use that term—but it is the operational backbone that makes D1.1 compliance auditable and sequenced for a real production environment.

Understanding the ITP as a document type, and how it connects to your WPS and NDE documentation, is practical knowledge for any QC manager running a structural steel fab shop.

What an ITP Is and Is Not

A quality control plan (QCP) is a general policy document. It describes what the shop's quality program includes: its organization, document control approach, calibration program, nonconformance reporting system, and reference to the codes it works under. A QCP answers "what does your quality system cover?"

An inspection test plan is more granular and project-specific. It answers "at each step of fabricating this specific structure, who does what inspection, when, and what do they do if it fails?" The ITP is keyed to the production sequence—raw material receipt, fit-up, preheat, welding, post-weld NDE, dimensional check, final coating—and assigns an inspection activity and a sign-off level to each step.

The distinction matters because a QCP can be a static document that rarely changes, while an ITP is tailored to the project, the governing code, and the owner's inspection requirements.

Structure of a Welding ITP

Most welding ITPs follow a tabular format with columns for:

Activity / Description: The specific fabrication or inspection activity (e.g., "Pre-weld fit-up inspection of CJP groove joints").
Reference document: The WPS number, code clause, or NDE procedure being applied.
Acceptance criteria: The standard against which the activity is evaluated (AWS D1.1:2025 visual acceptance criteria, RT acceptance criteria, etc.).
Responsible party: Fabricator QC, contractor QC, owner/third-party inspector, or some combination.
Hold / Witness / Review: The notification level for each party.
Record: What document is generated (inspection report, radiograph, test record).

The hold/witness/review distinction is the core of the ITP. It is the mechanism by which the owner's inspector maintains oversight without being present for every weld in a large fab shop.

Hold Points in Structural Welding

A hold point is a hard stop. Production cannot proceed past that stage until the designated party reviews the work and signs the ITP. Common hold points in structural welding programs:

Material receiving. Verification that the base metal CMTRs match the specified grade and heat number, and that the material meets dimensional and surface quality requirements. An owner's inspector may hold the right to review CMTRs before any material is cut.

First-article fit-up inspection. On repetitive weld assemblies, the first piece is a hold so the inspector can verify that the joint design matches the WPS and that fit-up tolerances are within AWS D1.1 requirements before the shop runs a full production run.

Preheat and interpass verification on critical or CVN-required joints. Where the WPS requires minimum preheat per Table 6.6 or where Table 6.8 supplementary essential variables apply, some owners hold preheat verification on the first joint of a heat or joint type.

NDE acceptance before backgouging or back welding. On CJP groove welds requiring backgouging to the root, the ITP may hold the back side until the root pass on the initial side passes RT or UT, and the backgouge is inspected visually before the back pass is applied.

Final NDE review before paint or coating. Owner inspector sign-off on the RT/UT/MT/PT reports before the coating crew covers the welds.

See CWI Inspection Hold Points in Structural Fabrication for detailed guidance on what each hold-point inspection covers.

Witness Points and Notification Windows

A witness point is less restrictive. The inspector must be notified in advance (typically 24–72 hours, as specified in the contract) and given the opportunity to attend. If the inspector waives attendance or does not appear within the notification window, work may proceed—but the notification record (date, time, who was notified) must be documented.

Typical witness points in structural fabrication:

Preheat and in-process temperature monitoring.
Welder identification stamp application on weld joints.
Production welding of non-critical weld joints.
Dimensional inspection of completed assemblies before delivery.

The practical implication: for witness points, the shop's CWI or QC inspector typically performs the inspection regardless of whether the owner's inspector attends. The shop's records document compliance; the owner's inspector reviews those records at the next review point or audit.

Review Points

A review point is the least demanding category. It means the inspector is entitled to review a specific document at some stage—but the activity itself can proceed without waiting for that review. Review points typically cover routine paperwork: WPS records, PQR records, welder qualification records, material certifications.

At the start of a project, an owner's inspector will often conduct a document review session where they review the shop's WPS/PQR library, welder qualification records, and QC plan against the project spec. That initial review is typically a review point (or sometimes a hold point before any production welding begins). Once approved, routine production welding proceeds without further document holds.

Linking the ITP to WPS Documentation

The ITP references, but does not replace, the WPS. Each inspection activity in the ITP is tied to a specific acceptance standard—which usually means a WPS number or a code clause. When the pre-weld fit-up inspector checks the groove geometry, the reference document is the WPS for that joint and the applicable clause of AWS D1.1:2025 for groove weld geometry tolerances.

When the ITP shows "preheat verification per WPS-01," that reference makes the WPS part of the inspection chain. If the WPS specifies a minimum preheat of 150°F for that base metal and thickness, the inspector verifies that temperature against that WPS requirement. The ITP entry does not restate the preheat requirement—it points to the WPS where it lives.

This is why WPS document control matters: an out-of-date WPS in the field (an old revision that does not reflect a procedure change) will produce ITP records that reference the wrong requirements. See WPS Revision Control Best Practices for the revision tracking discipline that keeps the ITP references reliable.

Contractor QC vs. Owner Verification Inspection

AWS D1.1 distinguishes between the contractor's (fabricator's) quality control inspection and the owner's verification inspection. The contractor is responsible for ensuring that production work meets the contract requirements—they own the QC function. The owner (or their designated representative, which may be a CWI from a third-party inspection firm) verifies that the contractor's work is conforming.

This distinction maps directly onto the ITP: the fabricator's CWI typically performs and records all routine in-process inspections, while the owner's inspector holds sign-off authority at specified hold points and conducts witness inspections at key stages.

The ITP formalizes this split. A well-structured ITP prevents the confusion that occurs when everyone assumes someone else caught the problem: every activity has a designated responsible party and a designated sign-off level.

See Contractor QC vs. Verification Inspection Under AWS D1.1 for the code basis for this distinction.

NDE Documentation and the ITP

NDE activities are some of the most rigorously controlled points in a structural welding ITP. The ITP will specify:

Which joints require NDE, and at what sampling rate (100% RT, spot UT, 10% MT, etc.).
Which NDE method is to be used (consistent with the WPS and governing specification).
The NDE procedure and acceptance criteria reference.
Who may perform the NDE (personnel qualification level—typically ASNT Level II minimum for RT and UT).
Whether the NDE reports are a hold point (must be reviewed and accepted before painting) or a review point.

An NDE report sitting unreviewed in a file does not mean the weld was accepted. The ITP defines who must review it and at what stage. A common audit finding is NDE reports for which no formal acceptance decision is documented—the test was run, the film processed, the report filed, but nobody formally signed the accept/reject decision on the ITP. That gap creates legal and warranty exposure.

See NDE Documentation and the Audit Packet for how NDE records fit into the full documentation package.

Building an ITP for a New Project

If your shop is preparing an ITP for a new structural contract, the starting point is the contract specification and governing code. Read the spec carefully for:

Which inspection activities are owner hold points vs. witness points.
Notification lead times required before hold/witness activities.
Required format or template for the ITP (some owners supply a blank ITP template as part of the specification package).
Required personnel qualifications (CWI, ASNT Level II) for each activity type.

Map those requirements against your production sequence, then draft the ITP activity by activity through the fabrication flow. Have the draft reviewed by the owner's inspection representative before production begins—resolving ITP disagreements on paper is far easier than resolving them in the middle of production.

For shops looking to manage WPS documents, welder qualifications, and NDE records in a single system that makes ITP documentation pull-ready, WPS Welding's platform keeps qualification records and NDE documentation organized and searchable.

When No ITP Exists

On smaller structural contracts—local fab shops doing miscellaneous steel for a commercial general contractor, for example—there may be no formal ITP requirement. The code minimum still applies: visual inspection by the fabricator's CWI, any NDE required by the specification, and documentation of welder qualifications and WPS applicability.

The absence of an ITP requirement does not reduce the documentation obligation. The records that an ITP would have generated—inspection reports, preheat verification, NDE results—still need to exist. An ITP is a system for generating and organizing those records; the records themselves are a D1.1 requirement regardless of whether an ITP was mandated.

For a CWI performing inspections without a formal ITP framework, the daily inspection report and the weld map are the practical substitutes. See CWI Daily Inspection Report Documentation Under AWS D1.1 for what those records should contain.

Rule library based on AWS D1.1:2025; verify against your governing edition, as the AHJ or contract may specify an earlier edition.