TPI (Third-Party Inspection)
/glossary/tpiIndependent inspection by a named agency against an inspection and test plan, not a mill MTC.
TPI is independent inspection of a named lot against the PO and ITP. Kanpur PWD, JJM, and sugar-mill buyers name SGS, Bureau Veritas, Lloyds, or TUV when the tender requires it. It is not an MTC and not Form III-C; IBR tubes take Form III-B. RP Sales coordinates TPI at Bartan Bazar when the RFQ names the agency, and prices the inspection line at GST 18% extra with the tax invoice carrying the rate actually in force.
In detail
Third-Party Inspection (TPI) is independent verification of a named lot against the purchase order and inspection plan. Indian projects may name SGS, Bureau Veritas, Lloyds, or TUV. TPI is not automatic on every API, PWD, or IBR order. TPI witnesses or reviews the tests; it does not sign the IBR tube form itself. RP Sales coordinates TPI at the Kanpur yard when the RFQ names the agency.
What TPI is, and what it is not
A third-party inspector works for the purchaser or for an official regulation, not for the rolling-mill production desk. The inspector examines the ordered lot against the contract, the product specification, and the agreed inspection and test plan. ISO/IEC 17020:2012, already named on the TPI process page, describes inspection-body competence and impartiality, including Type A third-party bodies.
TPI is an activity: witness, review, or release. It is not the mill test certificate; the mill still issues chemistry and mechanical results on an MTC. Ask specifically for EN 10204 Type 3.2 when the ITP needs an independent countersignature, since a plain Certificate of Conformity from the same visit may not meet that specification; name the document on the PO rather than the visit.
TPI is not an IBR form by default; the recognised authority for that duty must sign the applicable form through the official route before it counts. Form III-A covers steam pipes, Form III-B covers tubes, and Form III-C covers boiler mountings and fittings. See the TPI process walkthrough for the full stage-by-stage booking sequence.
TPI is not a BIS licence and not an ISI mark. It does not turn the wrong grade into the right grade. A Kanpur stock walk-around cannot recreate a mill tensile or hydrotest that already happened.
Who should specify TPI, and who should not
Specify TPI when the tender, PO, inspection plan, purchaser, or applicable authority requires independent inspection. Oil and gas line pipe takes TPI when the contract names PSL 2 or a nominated agency. Public-sector PWD and JJM lots take TPI when the tender document names it. First orders from a new mill or grade take TPI when the buyer names it on the RFQ.
Sugar-mill and Panki boiler tubes follow the IBR inspecting-authority path on the approved plan. Hydraulic and printing-cylinder shops in Dada Nagar should specify TPI only when the drawing or end customer names dimensional or material witness. Fire-system and borewell contractors add TPI when the municipal engineer names an agency.
Do not add TPI automatically to an ordinary stock pickup of IS 1239 Medium at Bartan Bazar whose approved document set already defines mill certification and receiving checks. Do not add TPI to hide an incomplete specification. The inspector measures the PO, not a trade nickname.
Do not treat SGS, Bureau Veritas, Lloyds, or TUV as a standing roster. Indian projects may also name IRClass, RINA, or DNV. Use the organisation and individual accepted by the purchaser and any governing authority.
Inspection documents for a Kanpur PO
Keep the activity, the mill certificate, and the IBR form on separate lines. The table below reuses the EN 10204:2004 types already compared on the quality hub and the TPI process page.
| Document | Who validates it | Test results | Typical Kanpur use |
|---|---|---|---|
| EN 10204 Type 2.2 | Manufacturer | Non-specific | Not a lot certificate |
| EN 10204 Type 3.1 | Mill authorised inspector | Specific to the lot | Standard B2B when the PO accepts it |
| EN 10204 Type 3.2 | Mill plus independent inspector | Specific to the lot | When the ITP names 3.2 |
| TPI Certificate of Conformity | Named TPI agency | Checks witnessed or reviewed under the ITP | Only if the PO names this paper |
| Applicable IBR form | Recognised authority for the duty | Results recorded on III-A, III-B, or III-C | III-A pipe, III-B tube, III-C mounting |
Type 3.1 is the mill inspection document commonly named on industrial POs. Type 3.2 adds independent validation. A TPI visit can support Type 3.2 when the inspector signs that certificate. The same visit can issue only a Certificate of Conformity. Those papers are useful, but they are not Type 3.2 unless they meet EN 10204.
How to specify TPI on an RFQ
Book TPI on the PO before the mill dates the heat. A late nomination cannot witness a test that already happened. RP Sales turns around a technical and commercial RFQ response inside 4 working hours, then coordinates mill access and dispatch after the TPI release note when the RFQ names the agency.
- Product: process, grade, NB or OD, wall or class, length, end finish, coating, quantity.
- Agency: SGS, Bureau Veritas, Lloyds, TUV, or the buyer-nominated body. Name the office and inspector scope.
- Document: Type 3.1, Type 3.2, Certificate of Conformity, and the IBR form if the line is boiler-related (III-A steam pipe, III-B tube, III-C mounting or fitting).
- ITP: visual, dimensional, marking, chemistry sample, tensile, bend, impact, hydrotest, NDE. Mark each as review, witness, or hold.
- Location: mill works for process tests; Bartan Bazar yard for stock, marking, and papers.
- Who pays: inspector fee, travel, waiting, retest, cancellation. TPI is a separate line on the quotation.
- Delivery: name ex-warehouse Kanpur or a defined FOR destination. GST 18% extra. Packing and heat identity preserved for the inspector.
Worked mass check for a TPI lot
The theoretical plain-end steel mass formula is W = (OD − t) × t × 0.02466 kg/m, with OD and wall in millimetres. The inspector uses the same arithmetic to sanity-check billed metres against the wall on the MTC.
Take 50 NB Medium IS 1239 from the site class chart and pipe-weight table: OD 60.3 mm, wall 3.6 mm. W = (60.3 − 3.6) × 3.6 × 0.02466 = 5.03 kg/m. A 6 m length is 30.2 kg. One hundred lengths are 3.02 MT before coating or threading.
The MS ERW price list band for 50 NB Medium is ₹53-60 per kg ex-warehouse Kanpur as of 24 May 2026, GST 18% extra. That steel line is about ₹1.60 lakh to ₹1.81 lakh before GST and freight (3.02 × 53,000 = 160,060; 3.02 × 60,000 = 181,200). TPI sits on a separate quotation line. Do not fold an invented percentage into the rupee-per-kg band.
The inspector matches heat number, OD, wall, length count, and MTC to that 3.02 MT. A large mass shortfall on the weighbridge is a hold. The underlying stock window for a Kanpur-yard TPI lot is 3-7 days as listed on the glossary lead-time entry; inspection scheduling determines the lot's actual release. Ask the quotation to state the inspector's available date.
Common TPI mistakes on pipe orders
The most common failure is booking after rolling. Specific inspection has to see the tests. A Type 3.2 request on a finished Kanpur bundle is too late for mill witness.
The second failure is calling every paper a TPI certificate. Write Type 3.2 or the exact IBR form when required. A short Certificate of Conformity is not automatically either.
The third failure is applying one wall tolerance to every product. The inspector must use IS 1239 class tables, IS 3589, ASTM A53, or the precision-tube standard on the PO. Do not import a seamless mill offer onto class pipe.
The fourth failure is using an inspector without the required IBR recognition. A global brand does not replace the approval required for Form III-B on a tube heat. Verify the authority record before the visit.
The fifth failure is treating a Kanpur yard walk-around as mill Type 3.2. Stock inspection can check marking, OD, wall, length, and papers. It cannot recreate tensile or hydrotest witness.
Standards and compliance for TPI
EN 10204:2004 defines Type 2.1, Type 2.2, Type 3.1, and Type 3.2 inspection documents. Type 3.1 is validated by the manufacturer's authorised inspection representative independent of manufacturing. Type 3.2 adds validation by the purchaser's representative or an inspection representative designated under official regulations.
ISO/IEC 17020:2012 covers inspection-body competence and impartiality. ISO/IEC 17025 covers testing laboratories. A 17025 lab report is not the same document as a 17020 inspection release. Keep those accreditations distinct on the PO.
The Indian Boiler Regulations, 1950 forms index puts steam pipes on Form III-A, tubes on Form III-B, and boiler mountings and fittings on Form III-C. For IBR work, the inspector must be the recognised Inspecting Authority for that duty.
API 5L line-pipe contracts add TPI when the quality plan names PSL 2 or a nominated agency. That requirement comes from the contract, not from the three letters TPI. See the TPI process walkthrough and EN 10204 Type 3.1 vs 3.2.
Buying TPI inspection in Kanpur
The Bartan Bazar / Basanti Nagar yard (208014) is the stock hold point. Mill inspection happens at the producing works. Name both locations on the ITP. Panki is about 12 km, Dada Nagar about 8 km, and Jajmau about 10 km from that yard.
PWD and JJM contractors should follow the agency and hold points named by the tender. Sugar-mill boiler tubes follow the IBR path. Hydraulic and printing-cylinder shops around Dada Nagar should attach the dimensional ITP their drawings require.
RP Sales coordinates pre-dispatch inspection by Bureau Veritas, SGS, TUV, Lloyds Register, or any buyer-nominated agency. We arrange mill access, witness the dimensional and hydrostatic tests named on the ITP, and dispatch only after the TPI release note is issued.
RP Sales dispatch coverage from Kanpur spans Uttar Pradesh, Bihar, Madhya Pradesh, Delhi NCR, and Uttarakhand daily. See steel pipes in Kanpur, MS ERW in Kanpur, seamless pipes in Kanpur, and the Kanpur steel market. Send the ITP with the RFQ.
Mill witness versus Kanpur yard check
Mill TPI watches the tests the product standard requires: chemistry sample, tensile, flattening, hydrotest, NDE. Those events happen at the works before the bundle is painted or packed. Book the agency before the mill dates the heat.
Kanpur yard TPI checks identity. The inspector matches stencil, heat number, OD, wall, length, end finish, and quantity to the PO and the MTC. That check is useful for stock already in Bartan Bazar. It is a different activity from mill witness.
If the lot is already in Kanpur stock, a TPI agency can still check marking, dimensions, and papers. For tensile or hydrotest witness, book TPI at the mill on the next heat. Do not promise Type 3.2 on a finished yard bundle.
A mixed load to Lucknow or Patna can carry more than one heat. Reconcile each heat with its own MTC and, if named, its own TPI release. A single CoC covering two heats is a discrepancy.
Hold points on the inspection plan
The ITP should list hold points before the mill dates the heat. A hold point stops work until the named inspector releases it. A witness point runs only if the inspector attends. A review point is a document check after the test.
Chemical and mechanical sampling follow the product standard's requirement, not a free choice on the inspection day; the TPI process walkthrough sets out the full stage sequence from pre-inspection meeting through release, including how hydrotest pressure and hold time trace back to that same standard or the PO.
Dimensional checks use the pipe or tube standard on the order, since class-pipe and precision-tube limits are not interchangeable. The inspector measures against that named standard and the PO, never against a figure copied over from a different product family.
Write the hold points on the RFQ so the quotation can price attendance, waiting, and retest. TPI cost and timing sit on that quotation. Do not treat a 5-10 day adder as a standing commercial rule.
Release note and the dispatch pack
The TPI release note is the inspector's permission to pack and load. RP Sales dispatches a TPI lot only after that note is issued. Keep the release with the MTC, packing list, and challan.
The dispatch pack for a Kanpur TPI lot is the MTC (Type 3.1 or 3.2 as named), the TPI release or CoC, Form III-B when the line is an IBR tube, Form III-C when the line is a mounting or fitting, the dispatch challan, and the e-way bill or railway receipt.
For the inspection invoice, GST is 18% extra as the budgeting basis; the tax invoice applies the rate in force. TPI fees, if billed through RP Sales, appear as a separate line. Bank charges on an LC stay on the credit, not on the inspection invoice.
Failed material stays segregated at the yard. Raise a rejection note with heat number, failed check, and governing requirement. Retest, concession, or replacement follows the PO and the approved quality plan.
Where you'll meet this in procurement
You will meet TPI (Third-Party Inspection) in inspection plans, dispatch packs, and tender checklists. Keep heat identity, certificate type, and any third-party witness tied to the order so TPI (Third-Party Inspection) is usable evidence at site acceptance—not a loose attachment after delivery.
Related terms
Related resources
Key points
- TPI is independent witness, review, or release against a named ITP, not mill QA and not a BIS licence.
- Type 3.2 and IBR Forms III-A, III-B, and III-C are named documents; a CoC is not automatically any of them.
- Book the agency and hold points on the PO before the heat is tested.
- Kanpur stock inspection cannot replace mill witness of tensile or hydrotest.
- RP Sales coordinates SGS, Bureau Veritas, Lloyds, or TUV when the RFQ names the agency, and dispatches after the release note.
Frequently asked questions
Sources
- EN 10204:2004. Metallic products. Types of inspection documents (2.1, 2.2, 3.1, 3.2) (European Committee for Standardization (CEN))
- ISO/IEC 17020:2012. Conformity assessment. Requirements for the operation of various types of bodies performing inspection (Type A third-party bodies) (International Organization for Standardization)
- ISO/IEC 17025. General requirements for the competence of testing and calibration laboratories (International Organization for Standardization)
- Indian Boiler Regulations, 1950. Forms index: III-A steam pipes, III-B tubes, III-C boiler mountings and fittings (Central Boilers Board, Government of India)
- RP Sales TPI process guide. Third-Party Inspection Process — SGS / BV / Lloyds / TÜV walkthrough (RP Sales Corporation)
- RP Sales MTC guide. How to Read a Mill Test Certificate — field-by-field guide for Indian buyers (RP Sales Corporation)