A practical, code-referenced guide to building an ITP that passes AI review, satisfies Aramco AVL vendor requirements, and holds up on the shop floor.

1. What an Inspection and Test Plan Actually Is

An Inspection and Test Plan, or ITP, is the document that turns a pressure vessel’s code requirements into a sequenced, verifiable shop-floor checklist. It lists every inspection and test that must happen during fabrication — from incoming material verification through final hydrostatic test and stamping — along with the applicable code or standard, the acceptance criteria, who performs each check, and who must witness or review it before work can proceed.

Where a WPS tells the welder how to make a joint and a PQR proves the procedure works, the ITP is the control document that ties the whole fabrication sequence together. It is the single reference an Authorized Inspector (AI), a client’s third-party inspector, or an Aramco representative will ask for first when they walk onto the shop floor, because it tells them exactly where the job stands and what evidence should already exist.

2. Why Pressure Vessels Need a Formal ITP

Pressure vessels built to ASME Section VIII Division 1 or Division 2 are safety-critical equipment operating under internal or external pressure, often alongside flammable or toxic process fluids. The code does not leave inspection sequencing to chance — UG-90 through UG-103 set out the examination and certification requirements the fabricator and the AI must jointly satisfy before the vessel can be stamped.

For Saudi Aramco-approved vendors specifically, the ITP is a mandatory submittal reviewed against the applicable Aramco Engineering Standard and Inspection Requirements before fabrication release. A vessel that fails to establish clear, code-referenced hold points at the ITP stage risks rework, re-inspection, or outright rejection of the certification package late in the job — the most expensive point at which to discover a gap.

3. The Core Structure of a Pressure Vessel ITP

Every credible ITP is built as a row-by-row activity log spanning the full fabrication sequence, using the H / W / R notation to define each party’s involvement:

• H — Hold Point: work cannot proceed until the inspector physically witnesses and signs off
• W — Witness Point: the inspector is notified and may choose to attend, but work can continue if they waive it
• R — Review Point: the inspector reviews documentation/records only, no physical attendance required

This table is illustrative — the actual hold/witness split, test pressure factor (1.3× for Division 2, 1.5× for Division 1 as a baseline before overpressure protection derating), and referenced code paragraphs must be set against the specific vessel’s design spec, client Inspection & Test Requirements (ITR), and code edition in force for the contract.

4. Step-by-Step: Writing the ITP

1. Start from the design and fabrication drawings. Identify every weld category (A, B, C, D per ASME VIII Fig. UW-3), material type, and thickness range — these drive which NDE methods and acceptance criteria apply.
2. Pull the governing code edition and client specification. Confirm whether the contract references the latest ASME BPVC edition/addenda or a fixed edition, and layer in any Aramco Engineering Standard (SAES) or client-specific ITR on top of code minimums.
3. List activities in fabrication sequence, not by discipline. Buyers and inspectors read an ITP top-to-bottom as the job progresses, so structure it as a timeline: receiving, fit-up, welding, NDE, heat treatment, pressure test, final inspection.
4. Assign H/W/R status to each party for each line — typically Fabricator QC, Client/Third-Party Inspector (TPI), and the Authorized Inspector (AI). Be conservative: under-assigning hold points is the most common reason ITPs get sent back during review.
5. Reference the exact code paragraph or standard clause for every acceptance criterion — not just “per ASME Section VIII” but the specific subsection (e.g., UW-51 for RT acceptance, UG-99 for pressure test). Vague references slow down AI and client approval.
6. Cross-check against the WPS/PQR package and the MDR index so hold points in the ITP match the records that will actually be generated — an ITP that promises documentation the MDR doesn’t produce is a common audit finding.
7. Route for approval before fabrication starts. The ITP is normally submitted to the client/TPI and AI for review and signature prior to material cutting, not after — retroactive ITPs carry far less weight in an audit.

5. ITP vs. QCP — Don’t Confuse the Two

An ITP is often confused with a Quality Control Plan (QCP), but they serve different purposes. The QCP is the fabricator’s broader quality management framework — procedures, personnel qualifications, calibration control, and organizational responsibilities. The ITP is a project-specific execution document derived from the QCP, listing the actual inspection and test sequence for one particular vessel or job. A strong QCP makes writing a compliant ITP faster because the underlying procedures it references are already qualified and on file.

6. Final Thought

A well-built ITP is not paperwork for its own sake — it is the sequencing tool that keeps a pressure vessel job moving without rework, and the document an AI or Aramco inspector uses to judge whether a fabricator’s quality system is genuinely under control or just claimed on paper. Getting the hold points, code references, and MDR alignment right at the planning stage is far cheaper than discovering a gap mid-fabrication or, worse, during final stamping.