An ITP (Inspection and Test Plan) is a project quality control document used to define inspection activities, test requirements, acceptance criteria, responsible parties, and release rules before valve manufacturing begins. In most valve procurement projects, the manufacturer or vendor prepares the ITP based on the purchase order, project specification, applicable standards, and purchaser inspection requirements. The document is then submitted to the purchaser, owner, end user, or authorized third-party inspection agency for review and approval.
A practical valve ITP should not only list inspection stages. It should also define when production must stop, when the inspector must be notified, which records must be reviewed, and what evidence is required before the valve can proceed to the next operation. ISO 10005 provides guidance for quality plans and is a useful reference when preparing project-specific quality control documents[1].
| Inspection Point | Control Strength | Release Rule |
|---|---|---|
| Hold Point (H) | Highest | Work cannot proceed until the defined party has inspected, accepted, and released the activity. |
| Witness Point (W) | Medium | The manufacturer notifies the inspector before the activity. If attendance is waived or the inspector does not attend within the agreed notice rule, work may proceed only if the approved ITP allows it and complete records are retained. |
| Review Point (R) | Document control | Records are submitted for review, confirmation, and archiving according to the approved document review scope. |
ITP Fundamentals
Three Inspection Point Types
Valve ITPs commonly use Hold Points, Witness Points, and Review Points to classify inspection control. The exact wording and authority should always be defined in the approved ITP, contract, and project specification. General definitions of hold and witness points are also widely used in construction and quality control procedures, where a hold point prevents work from continuing without authorization, while a witness point gives the designated party the opportunity to attend after notification[2].
- Hold Points (H): A hold point is a mandatory stop. The manufacturer cannot continue past the defined operation until the responsible party has verified the activity and released it. Hold points are normally used where the activity is safety-critical, code-critical, not easily repeatable, or difficult to inspect after the next manufacturing step.
- Witness Points (W): A witness point is a planned inspection opportunity. The manufacturer must notify the responsible inspector within the agreed notice period. If the inspector attends, the activity is witnessed and recorded. If attendance is waived or no attendance occurs within the agreed rule, continuation is allowed only when the approved ITP permits it and objective evidence is retained.
- Review Points (R): A review point is a document-control milestone. Records such as MTCs, welding records, NDE reports, calibration certificates, pressure test reports, dimensional reports, and NCR close-out evidence are submitted for review and retention.
ISO 9001:2015 defines quality management system requirements and emphasizes controlled operation, documented information, nonconforming output control, and corrective action. It does not prescribe a fixed valve ITP format, but it supports the need for controlled production, evidence of conformity, and traceable release records[3].
The selection of H, W, and R points should be based on manufacturing risk, valve design, pressure class, material criticality, service condition, project specification, and purchaser inspection requirements. API 6D is widely used for pipeline valves and defines manufacturing requirements for pipeline valve products[4]. For API 6D pipeline ball valves, the ITP should also align with the valve data sheet, approved drawings, quality plan, and purchaser inspection assignment.
- Pressure boundary tests are commonly controlled as H Points in critical oil and gas valve projects because failed results directly affect release.
- Material receiving inspection may be controlled as W, R, or H depending on material criticality, traceability risk, and contract requirements.
- Document review points should be strong enough to verify traceability but should not replace mandatory physical inspection when the approved ITP requires on-site release.
Further reading: API 6D High-Pressure Ball Valve Standard page.
Where H Points Should Stop the Process
Any manufacturing step that can permanently affect pressure integrity, sealing performance, material traceability, or in-service safety should be evaluated for H Point control.
Hold points should be used carefully. They are powerful quality control gates, but excessive hold points can delay production because each one requires formal release before the next operation begins. Hold points are most useful when the result cannot be fully verified later, when the cost of rework would be high, or when the activity directly affects pressure boundary safety.
For valve manufacturing, common H Point candidates include shell hydrostatic testing, final seat testing where required by the purchaser, critical welding repair release, post-repair pressure testing, and final inspection before shipment. Material release before machining may also be assigned as an H Point for special alloys, low-temperature service, sour service, or end-user-critical applications.
A common failure mode occurs when a supplier performs a hold-point activity and then continues assembly before the owner or third-party inspector arrives. Once the valve is assembled, it may become difficult to confirm whether the required test was performed under the correct pressure, duration, medium, calibration condition, and acceptance criteria. In that situation, the purchaser may require re-testing, additional witness inspection, or formal concession review.
| Common H Point | Reason for Holding | Typical Requirement |
|---|---|---|
| Shell hydrostatic test | Confirms pressure boundary strength | For many steel and alloy valves, API 598 and ASME B16.34 are commonly referenced for shell test requirements. ASME B16.34 covers pressure-temperature ratings, materials, nondestructive examination requirements, testing, and marking for applicable valve types[5]. The exact test pressure, hold time, and acceptance criteria should be confirmed against the applicable standard edition and project specification. |
| Low-pressure closure test | Confirms seat sealing performance before release | API 598 covers inspection, examination, supplementary examinations, and pressure test requirements for several valve types, including ball, gate, globe, plug, check, and butterfly valves[6]. For many steel and alloy valves, industry summaries commonly list low-pressure closure testing at 80 +/- 20 psig and high-pressure closure testing based on 110% of the applicable pressure basis, but final values must be checked against the purchased official standard and project requirements[7]. |
| Critical welding repair release | Prevents nonconforming pressure-retaining repair from being hidden by later work | Repair welding should follow approved WPS/PQR/WPQ, applicable material requirements, NDE requirements, repair maps, heat treatment requirements where applicable, and purchaser approval rules. |
| Final inspection before shipment | Confirms readiness for packing and dispatch | Final dimensional inspection, marking, nameplate, coating, documentation, test reports, NCR status, and packing condition should be verified before release. |
H Point quantity should be risk-based rather than fixed by a universal number. A small valve package with standard service may need fewer hold points, while a critical pipeline valve package with special materials, welding, fire-safe requirements, or fugitive emission requirements may need more. The ITP should avoid both extremes: too few hold points can miss irreversible risks, while too many hold points can create unnecessary schedule bottlenecks.
Further reading: WCB vs Forged Duplex Stainless Steel Valves comparison page.
What Happens If No One Witnesses a W Point?
Witness Points are designed to keep inspection visibility without stopping every production step. The manufacturer should notify the inspector in writing according to the notice period defined in the contract, approved ITP, purchase order, or project specification. The notice period should not be presented as a universal standard value. Some projects use 24 to 48 hours, while international procurement projects may require several working days depending on travel, inspector availability, and agency assignment.
If the inspector does not attend, or formally waives attendance, the manufacturer may continue only when the approved ITP allows continuation after the agreed notice rule. The manufacturer must still keep objective evidence. A defensible W Point record should include the inspection date, operation number, applicable acceptance criteria, calibrated instrument details where applicable, measured results, inspector or operator name, photos where useful, and reference to related drawings or reports.
- The supplier sends the W Point notification in writing.
- The owner, purchaser, third-party inspection agency, or inspector confirms attendance, waives attendance, or does not respond within the agreed period.
- If the approved ITP allows continuation, the supplier performs the activity and records the results.
- The supplier submits the completed record package for later review.
- The purchaser or TPI reviews the evidence at the next R Point or final document review stage.
W Points should not be used as a shortcut for critical activities that require mandatory release. If the purchaser wants the activity to stop until inspection is completed, the point should be defined as an H Point. Upgrading a W Point to an H Point, or downgrading an H Point to a W Point, should be treated as an ITP change and approved in writing before implementation.
- If the inspector attends, conduct witnessing and sign the record according to the approved ITP.
- If the inspector cannot attend and the ITP permits continuation, submit complete operation records and test data.
- If the W Point evidence is incomplete, the purchaser may require additional inspection, re-testing, or NCR review.
Further reading: Heavy-Duty Small-Port Ball Valve Export Cases page.
Inspection Items
Raw Material Receiving Inspection
Raw material receiving inspection is one of the earliest control gates in the valve ITP chain. If incorrect material, incomplete traceability, or nonconforming chemistry enters machining, welding, or assembly, the error may become difficult and expensive to correct later.
For pressure-containing valve parts, the ITP should require material grade confirmation, heat number verification, MTC review, traceability marking, and any project-required PMI or laboratory testing. ASTM A216/A216M covers carbon steel castings for valves, flanges, fittings, and other pressure-containing parts for high-temperature service, including grades WCA, WCB, and WCC[8]. When ASME material specifications are required by the project, ASME BPVC Section II-A provides ferrous material specifications for pressure equipment applications[9].
The ITP should not rely on a generic “PMI check” statement when carbon content is important. Common handheld XRF PMI can identify many alloying elements, but it cannot measure carbon because carbon is lighter than magnesium. For carbon steel grade separation or carbon-limit verification, the ITP should require a suitable method such as laboratory chemical analysis, portable OES, or carbon-capable LIBS/OES equipment, depending on accuracy requirements and project acceptance rules[10].
| Inspection Item | What to Check | Typical Record |
|---|---|---|
| MTC verification | Heat number, material grade, chemical composition, mechanical properties, heat treatment condition, and supplementary requirements | Mill test certificate and heat number traceability record |
| Traceability check | Heat number transfer, casting identification, stamping, tagging, and link between part marking and MTC | Receiving inspection report and traceability map |
| PMI spot check | Instrument type, calibration status, tested elements, test location, material grade, and acceptance basis | PMI report and test point photos |
| Carbon verification | Carbon content where grade acceptance depends on carbon limit | OES/LIBS report or laboratory chemical analysis report |
| Mechanical testing review | Tensile properties, impact testing where specified, hardness where required, and heat treatment condition | Tensile test report, impact test report, and hardness report where applicable |
| Visual and dimensional inspection | Surface condition, casting quality, machining allowance, dimensions, and identification marks | Receiving inspection report |
Raw material inspection is often assigned as a W Point or R Point. For critical pressure-containing parts, special alloys, sour service, cryogenic service, low-temperature service, or end-user-critical applications, the purchaser may require H Point release before machining.
Further reading: Forged Soft-Seated Ball Valve page.
Welding NDE
Welding is one of the main defect-generating processes in valve manufacturing. The ITP should control welding procedure qualification, welder qualification, welding consumables, preheat, interpass temperature, weld identification, repair welding, NDE method, NDE extent, acceptance criteria, and record review.
WPS, PQR, and WPQ review should be completed before welding starts. ISO 15614-1 specifies how preliminary welding procedure specifications are qualified by welding procedure tests and defines qualification ranges for welding procedures within its scope[11]. The applicable welding qualification route should be confirmed against the project specification, material type, welding process, and governing code.
- WPS/PQR/WPQ review is commonly controlled as an R Point, W Point, or H Point depending on project risk.
- Pressure-retaining weld NDE is commonly controlled as a W Point unless the contract requires hold before release.
- Weld repair acceptance may require H Point release when the repair affects the pressure boundary or sealing performance.
For pressure-retaining welds, the ITP should clearly define the required NDE method and coverage according to drawings, material, weld configuration, applicable standard, service risk, and purchaser requirements. Avoid stating universal wall-thickness thresholds for RT or UT unless the project specification defines them. NDE method selection depends on defect type, geometry, accessibility, wall thickness, material, sensitivity, safety constraints, and acceptance criteria.
| NDE Method | Best For | Typical Application |
|---|---|---|
| RT radiography | Volumetric internal defects such as porosity, slag inclusion, and lack of fusion in suitable geometries | Often used for butt welds or shell welds where geometry, thickness, access, radiation safety, and acceptance criteria support radiographic examination |
| UT ultrasonic testing | Planar defects and thicker sections where ultrasonic access is suitable | Often used for heavier butt welds, pressure-retaining welds, or cases where RT is limited by thickness, access, or safety conditions |
| PT liquid penetrant testing | Surface-breaking defects on nonporous materials | Commonly used after welding, machining, cleaning, repair, and final surface preparation |
| MT magnetic particle testing | Surface and near-surface defects in ferromagnetic materials | Commonly used for carbon steel and low-alloy steel welds after surface preparation |
The ITP should also specify who reviews NDE reports, who approves repair maps, which acceptance standard applies, and whether re-examination is required after repair. For critical welds, the release record should link the weld map, welder ID, WPS number, NDE report number, repair status, and final acceptance conclusion.
Further reading: Forged Metal-Seated Ball Valve page.
Final Testing
Final testing is the last major quality gate in the valve ITP chain. It provides direct evidence of pressure boundary integrity, sealing performance, assembly quality, and release readiness. API 598 covers inspection, examination, supplementary examinations, and pressure test requirements for several valve types, while API 6D and project specifications may add pipeline valve requirements, documentation requirements, or purchaser-defined tests[6][4].
Final pressure testing is commonly assigned as an H Point for critical oil and gas valves. However, the inspection point designation should always follow the approved ITP, contract, and project specification. A standard should not be interpreted as automatically creating a purchaser hold point unless the approved ITP or contract requires it.
| Test Item | Typical Requirement | Use Condition |
|---|---|---|
| Shell hydrostatic strength test | Confirm pressure boundary integrity using the test pressure, medium, hold time, and acceptance criteria required by the applicable standard and project specification. | Required where applicable by valve standard and project specification |
| High-pressure closure test | Confirm seat sealing under the applicable high-pressure closure test condition. Test direction depends on valve design, seat arrangement, and standard requirements. | Required where specified by valve type, standard, or project requirement |
| Low-pressure closure test | Confirm low-pressure sealing performance using the applicable gas test condition and hold time. | Required where specified by valve type, standard, or project requirement |
| DBB double-block-and-bleed verification | Verify independent sealing and bleed function for valves designed and specified for DBB service. | Where applicable |
| API 607 fire-safe test | API 607 specifies fire testing requirements and methods for confirming pressure-containing capability of quarter-turn valves with nonmetallic or metallic seats and other operated valves within its scope[12]. | Where contract, valve design, or service condition requires fire-safe qualification |
| ISO 15848 fugitive emission test | ISO 15848-1 specifies type testing and classification procedures for evaluation of external leakage of valve stem seals and body joints of isolating and control valves intended for volatile air pollutants and hazardous fluids[13]. | Where fugitive emission control is specified |
| Cryogenic test | Verify sealing and operation under the required low-temperature condition. | Where cryogenic service is specified |
Before final testing, the ITP should require confirmation that pressure gauges, pressure transducers, temperature instruments, torque tools, timers, and test benches are within valid calibration. Test records should identify the valve tag number, serial number, test medium, test pressure, test duration, test temperature where required, instrument ID, calibration status, acceptance criteria, leakage result, and inspector release status.
If leakage, pressure drop, abnormal deformation, gasket displacement, or seat damage is found during final testing, the valve should not be released by informal correction alone. The supplier should document the nonconformity, identify the cause, define corrective action, perform repair or replacement under approved procedure, and repeat the required test before release.
Further reading: Ball Valve Testing FAQ page.
Sign-Off and Release
Who Signs at Each Step
The signatory authority for each ITP inspection point depends on the approved ITP, contract, purchase order, project specification, purchaser inspection assignment, and third-party inspection arrangement. It should not be attributed to a valve product standard alone unless that standard clearly requires the specific record or release action.
| Point Type | Who Signs | Release Logic |
|---|---|---|
| H Point | Owner, purchaser, end user, or owner-authorized third-party inspection agency according to the approved ITP | The next operation cannot proceed until the activity is released. |
| W Point | Inspector signs if attending; manufacturer may continue after waiver or non-attendance only where the approved ITP allows it | The record is submitted for purchaser or TPI review. |
| R Point | Manufacturer prepares records; purchaser, owner, or TPI reviews according to the approved document review scope | The record package is reviewed and archived. |
Each sign-off record should be traceable and complete. At minimum, the record should identify the operation number, inspection item, applicable drawing or standard, inspection date, inspector name, organization, result, deviation description where applicable, signature, and linked report number.
- Operation number and inspection item
- Applicable drawing, procedure, standard, or acceptance criterion
- Inspection date and inspection location
- Inspector name, title, organization, and signature
- Inspection result, including PASS, FAIL, or accepted with concession where applicable
- Reference to related report, NCR, test certificate, calibration certificate, or photo record
Quality sign-off and production schedule control should be separated where practical. If the same person is responsible for both release authority and schedule pressure, the project has a higher risk of premature release, back-signing, or incomplete record review. If an audit identifies same-handwriting back-signatures, sign-off dates earlier than inspection dates, or records that conflict with the production timeline, the issue should be treated as a quality system risk and investigated.
Further reading: Carilo Technical Inquiry Contact page.
Third-Party Witness Arrangement
Third-party inspection agency engagement is common in international oil and gas valve procurement, especially for critical service, high-value packages, export projects, or end-user-mandated inspection programs. The third-party inspector’s authority should be defined by the contract, approved ITP, purchase order, project specification, and inspection assignment.
The ITP should define which points are witnessed, who sends notifications, how much advance notice is required, how waivers are handled, what records must be submitted, and whether the inspector has authority to stop work, reject nonconforming items, or require re-testing. ASME BPVC Section II-A and ASTM material standards can support material acceptance requirements, but they do not by themselves define the commercial authority of a third-party inspection agency[9][8].
| Witness Strategy | Coverage | Cost and Schedule Impact |
|---|---|---|
| Full H Point coverage | All approved H Points are witnessed and released before continuation. | Strong control for critical operations but requires careful scheduling. |
| Selected W Point sampling | W Points are witnessed based on batch risk, activity criticality, inspector availability, and purchaser requirements. | Balances inspection visibility with production efficiency. |
| Batch-end document review | R Points are reviewed in a consolidated document session before final release. | Reduces repeated visits but requires complete and traceable records. |
| Resident inspection | Inspector remains at the manufacturing facility during critical production stages. | Useful for high-risk packages but increases inspection cost. |
Inspection cost should not be stated as a fixed percentage of valve value. It varies by country, inspection agency, inspector qualification, daily rate, travel cost, standby time, batch size, production schedule, and number of H/W points. For small batches, third-party inspection may represent a high percentage of order value. For large valve packages, the percentage may be much lower.
Non-Conformance Report Closure
NCR (Non-Conformance Report) closure is one of the most heavily audited parts of the ITP lifecycle because it shows how the supplier controls deviations after they are discovered. ISO 9001:2015 includes requirements related to control of nonconforming outputs and corrective action, but the exact NCR format should be defined by the supplier QMS, contract, project specification, and approved ITP[3].
Every NCR should follow a standardized recording format.
- Sequential NCR number
- Discovery date and originating operation
- Valve tag number, serial number, heat number, weld number, or affected batch identification
- Detailed non-conformance description with quantified deviation data where applicable
- Requirement reference, such as drawing, procedure, standard, ITP item, or project specification
- Immediate correction or containment action
- Root cause analysis where required
- Corrective action and preventive action where applicable
- Verification evidence after corrective action is completed
- Closure approval by the authorized party after verification
NCR closure must happen after correction or corrective action is completed and verified. Closing an NCR before the repair, replacement, re-test, or engineering disposition is completed creates a record conflict and can become a major audit finding.
NCR closure is not a paperwork step. It is evidence that the nonconforming condition has been controlled, corrected, verified, and released according to the approved rule.
NCR closure should be controlled according to risk. NCRs affecting pressure boundary, sealing performance, material traceability, welding quality, testing validity, or safety should require formal purchaser or TPI review where the approved ITP requires it. Minor document NCRs may be closed through R Point review if the contract allows it and the missing evidence is later supplied and verified.
Simple NCRs may be closed quickly when the correction is clear and verification evidence is available. Major NCRs involving replacement, re-testing, welding repair, engineering concession, or owner approval should follow an approved corrective action schedule and should not be closed until objective evidence confirms acceptance.
Further reading: Ball Valve Selection FAQ page.
An ITP is not only a quality document. It is an execution plan for managing valve manufacturing risk.
A qualified valve ITP defines inspection points, release authority, acceptance criteria, document requirements, and NCR control in a way that matches the actual risk of the manufacturing process.
- High-risk operations are controlled through H Points with mandatory release before continuation.
- Medium-risk operations use W Points to balance inspection visibility and production efficiency.
- Low-risk documentation items are consolidated through R Points.
- Raw material receiving inspection secures traceability at the source.
- Welding NDE verifies process control and weld quality.
- Final testing provides direct evidence of pressure and sealing performance.
- Clear signatory authority, practical third-party witness planning, and disciplined NCR closure turn the ITP into a working execution document.
