How to prepare an Inspection and Test Plan (ITP).
A step-by-step guide to writing an ITP that catches defects, satisfies your client, and holds up at handover — hold points, witness points, acceptance criteria and clause references, done right.
An Inspection and Test Plan is the single document that tells the fabricator what to build, the inspector what to verify, and the client what to sign off before work continues. Weak ITPs are the single largest source of NCRs, schedule slippage and manufacturing data book gaps we see on capital projects.
A strong ITP is scope-specific, sequenced, clause-referenced, and unambiguous about who signs what and when. This guide covers the seven steps we use to prepare and approve ITPs for owners, EPCs and vendors across energy, infrastructure, manufacturing and pharmaceuticals.
Seven steps to a defensible Inspection and Test Plan
- Step 01ISO 9001:2015 · 8.1 · 8.5.1
Define the scope, sequence and interfaces before you write a line
Start from the process flow — receiving, fabrication, assembly, testing, preservation, shipping — not from a template. Map every discrete activity in the exact order it happens on the shop or site floor, mark the interfaces where responsibility changes hands (vendor to installer, mechanical to electrical, construction to commissioning), and identify the code, standard and project specification that governs each activity. Skip this and every subsequent line will need rework.
- Step 02ISO 9001:2015 · 8.5.1(a)
Write one line per discrete activity — never one line per phase
Each activity gets its own row: material receiving, fit-up, root pass, hot pass, fill, cap, visual, NDE, PWHT, hydrostatic test, final visual, preservation, packing. Aggregating them into 'welding' or 'testing' hides exactly the interfaces where inspectors need to intervene. If a step has different acceptance criteria, a different responsible party or a different record, it is a different line.
- Step 03ISO 9001:2015 · 7.5.3 · 8.5.1(b)
Reference the specific clause — not the standard's title
'AWS D1.1' is not a reference; 'AWS D1.1:2020 Table 8.1 acceptance criteria for statically loaded connections' is. Every line should carry the exact code, edition, clause or table plus the project specification section that governs it. When the project spec is more stringent than the code, cite both and mark the spec as the controlling document. This is what makes the ITP defensible at handover.
- Step 04ISO 9001:2015 · 8.5.1(c) · 8.6
Assign hold (H), witness (W), review (R) and surveillance (S) correctly
Reserve hold points for activities where the consequence of proceeding without verification is unrecoverable — first weld, pre-hydro walk-down, final closure, painting after inspection. Use witness points where attendance is desirable but the work can proceed on notice. Use review points for records-only checks. Overusing H stops your project; underusing it lets defects through. Every H and W needs a defined notification period — typically 24 to 72 hours — written into the ITP.
- Step 05ISO 9001:2015 · 7.2 · 8.5.1(d)
Nominate the responsible party and the verifying party per line
Two columns, not one. The 'responsible' party executes the activity (welder, painter, technician); the 'verifying' party signs off (QC inspector, third-party inspector, client representative). List them by role, not by name — 'Vendor QC Level II', 'TPI ASNT Level II UT', 'Owner's Engineer' — so the ITP survives personnel changes. Every hold and witness point needs a nominated attendee, not just a 'client' placeholder.
- Step 06ISO 9001:2015 · 7.5 · 8.5.1(e)
Specify the record — form number, revision, and where it lives
For every line, name the exact record: welder qualification WPQR, WPS, PQR, heat treatment chart, hydrotest chart, NDE report, visual report, punch list. Include the form number and revision, and state whether the record ships with the item, goes into the manufacturing data book, or into the project quality dossier. A record you cannot name is a record you will not find at handover.
- Step 07ISO 9001:2015 · 7.5.3 · 8.3.4
Route the ITP for review, approval and revision control
The vendor issues the ITP; the EPC engineer reviews; the owner's engineer approves as Code 1 / Approved. Every revision carries a new revision number, a change bar or revision cloud, and a change log. Work executed against a superseded ITP revision is work executed against an uncontrolled document — a classic Clause 7.5.3 finding. The approved ITP is the baseline against which every NCR, deviation and concession is judged.
The twelve columns every ITP should carry
Use this as the master column set. Individual projects will add columns for sampling rate, batch traceability or client-specific hold points, but these twelve are the minimum viable ITP header row.
| Column | What it contains |
|---|---|
| Item / Step | Numbered activity in strict process sequence. |
| Activity Description | One sentence, unambiguous — what is being done. |
| Reference / Procedure | Project spec section, WPS number, internal procedure ID. |
| Acceptance Criteria | The exact clause, table, tolerance or limit — no 'per code'. |
| Verification Method | Visual, dimensional, NDE method, functional test, documentation review. |
| Responsible | The party executing the activity, by role. |
| Inspection Point | H (Hold), W (Witness), R (Review), S (Surveillance) — one per line. |
| Vendor QC | H / W / R for the vendor's own quality control. |
| EPC / Contractor | H / W / R for the EPC or main contractor. |
| Owner / TPI | H / W / R for the owner or third-party inspection. |
| Record | The exact form number and revision generated at this step. |
| Remarks | Notification period, sampling rate, special instructions. |
Seven ITP mistakes that cause NCRs and schedule loss
Vague acceptance criteria
'Per code' or 'to standard' — with no clause. Defensible only until the first dispute.
Hold points on everything
Inspectors attend three times a day, work stops, schedule collapses. Reserve H for genuinely unrecoverable steps.
Missing notification periods
H and W without a written notice window (e.g. 48 hours) become de-facto surveillance points.
One line for 'welding'
Fit-up, root, fill, cap, PWHT and hydrotest each need their own line — different criteria, different records.
Signed off by the wrong role
A shop foreman signing a client hold point closes nothing. Verify signatures match the nominated role.
Records not traceable to heat / serial / weld number
The record exists but cannot be tied to the specific item — fatal at manufacturing data book handover.
Revision drift between shop and site
The shop is working to Rev 3, the inspector is auditing to Rev 4. Control ITP revisions at point-of-use.
An ITP the client, the regulator and the data book all accept.
On high-consequence projects — energy, infrastructure, pressure equipment, pharmaceuticals — the ITP is the contract between the vendor, the EPC and the owner about what will be verified and by whom. A weak ITP is discovered at handover, when the data book is short and the item is already installed.
Independent third-party inspectors prepare and review ITPs against the governing code, the project specification and the sector norms they see across dozens of similar projects — before fabrication starts, not after the NCR is written. That is the difference between an ITP that controls quality and an ITP that documents its absence.
Inspection and Test Plan questions we answer most often
- What is an Inspection and Test Plan (ITP)?
- An Inspection and Test Plan (ITP) is a controlled document that lists every inspection, test and verification activity for a scope of work — in sequence — with the acceptance criteria, reference standard, responsible party, record required, and the hold, witness or review point at each step. It is the single source of truth that tells the fabricator what to build, the inspector what to verify, and the client what to sign off before work continues.
- What is the difference between a hold point, witness point and review point in an ITP?
- A hold point (H) stops work — the activity cannot proceed until the nominated party has attended and signed. A witness point (W) invites attendance with notice, but work can proceed if the party does not attend within the notification window. A review point (R) or surveillance point (S) is a documentation check only — the record is reviewed after the fact. Mixing these three up is the most common ITP failure we see; it either grinds a project to a halt or lets critical activities slip past unverified.
- Who prepares the ITP — the contractor, the vendor or the owner?
- The party performing the work prepares the ITP — usually the fabricator, contractor or vendor — because they own the process, the sequence and the acceptance evidence. The owner or owner's engineer reviews and approves it, adds their own hold and witness points, and issues it as a Code 1 / Approved document before manufacturing or construction begins. On EPC projects the EPC contractor typically consolidates vendor ITPs into a master ITP for the package.
- What standards should an ITP reference?
- Every activity line should reference the specific clause of the applicable code, standard or project specification — not a general title. Common references include ASME B31.3 for process piping, AWS D1.1 for structural welding, API 650 / 620 for storage tanks, ASME Section IX for welder qualification, ASTM E165 for liquid penetrant, ASTM E709 for magnetic particle, and ISO 9001:2015 Clause 8.5 for production and service provision. Project specifications override where they are more stringent than the code.
- How detailed should an ITP be?
- Detailed enough that a qualified inspector who has never seen the job can pick it up and verify each step against unambiguous acceptance criteria. That usually means one line per discrete activity — not one line per phase. A structural weld package might run 40 to 80 lines; a pressure vessel 100+. If your ITP fits on one page and covers a month of work, it is a schedule, not an ITP.
- Do we need a separate ITP for each vendor and each package?
- Yes. ITPs are scope-specific and process-specific. A single vendor supplying two different products needs two ITPs. A fabrication shop and the installation contractor need separate ITPs even if the item is the same, because the inspection points, acceptance criteria and standards differ between shop and site. The master project ITP indexes these package ITPs; it does not replace them.
Need help preparing or reviewing an ITP?
Our inspectors and quality engineers prepare, review and approve ITPs for owners, EPCs and vendors across North America — with India and the UAE coming soon.