Valve procurement documentation: EN 10204 certificates, API 598 testing and MSS SP-25 marking.
- EN 10204
- API 598
- MSS SP-25
Valve procurement paperwork answers three questions: what material is this — EN 10204 certificates; was it tested — API 598 reports; and what am I looking at — MSS SP-25 markings. This guide explains each document, who issues it, and what a Malaysian buyer should require on the purchase order, because paperwork requested after delivery is far harder to obtain than paperwork required up front.
The three documents in one view
Every valve that matters arrives with three questions attached, and each has its own document. What is this made of? — answered by an EN 10204 material certificate, issued for the metal before it ever became a valve. Was it tested? — answered by an API 598 test report, issued for the finished valve after assembly. What am I looking at? — answered by the markings on the body and nameplate, standardised by MSS SP-25 so that a valve on a rack in Subang Jaya reads the same as one in a laydown yard offshore.
The three are not interchangeable and none implies the others. A perfect test report says nothing about material grade; a 3.1 certificate says nothing about whether the seats hold; a nameplate proves neither. Procurement that treats them as one “cert pack” discovers the difference at the worst possible time — during a client audit, after installation.
EN 10204 material certificates: 2.1, 2.2, 3.1, 3.2
EN 10204 defines four inspection document types, in rising order of independence. The working difference is who verified the material and against what: the low types declare compliance, the high types report actual test results from the specific material supplied, with an increasingly independent signature over them.
| TYPE | DOCUMENT | RESULTS SHOWN | VALIDATED BY |
|---|---|---|---|
| 2.1 | Declaration of compliance | None — statement only | Manufacturer |
| 2.2 | Test report | Non-specific — typical production tests | Manufacturer |
| 3.1 | Inspection certificate 3.1 | Specific — tests on the material supplied | Manufacturer’s inspection representative, independent of production |
| 3.2 | Inspection certificate 3.2 | Specific — tests on the material supplied | Manufacturer’s representative AND the purchaser’s or a third-party inspector |
For valve procurement the practical band is narrow: 3.1 is the routine ask for pressure-retaining parts, and 3.2 is reserved for the critical service that justifies paying an independent inspector to countersign. Choosing between them — and resisting the reflex to write 3.2 everywhere — is the subject of the 3.1 vs 3.2 memo.
API 598 test reports
API 598 is the inspection and testing standard the valve world defaults to: it defines the shell test that proves the pressure boundary, the closure tests that prove the seats, the test pressures and durations by size and class, and the leakage a given valve type is permitted to show. The report that answers it states what was tested and to what pressure, for how long, in what medium, with what result — a page of numbers tied to a serial number.
Read one properly once and it becomes a thirty-second check forever: pressures against the class, duration against the size, leakage against the acceptance column, serial number against the nameplate in front of you. The walkthrough — line by line, with what each figure is allowed to be — is in the API 598 memo. Note also what the report is not: proof of material, which remains the certificate’s job from DETAIL 02.
MSS SP-25 markings and the nameplate
Paper can be filed in the wrong cabinet; the marking travels with the valve. MSS SP-25 is the standard practice that says what a valve must carry on its body and nameplate and how: manufacturer’s identification, material designation, rating, size — cast or forged into the body where practice requires it, stamped on the nameplate with the rest. It is the reason a valve’s identity survives twenty years after its file has gone missing.
For procurement the marking is the reconciliation point where the paper meets the metal. The material grade on the 3.1 certificate should be the grade readable on the body; the rating on the nameplate should be the class on the test report and the purchase order. Ten seconds at goods-inwards closes that loop. How to read every field — and what the common abbreviations denote — is in the nameplate memo.
Who issues what
The chain has three links. The mill or foundry issues the material certificate — it existed before the valve did, which is precisely why nobody downstream can create one later. The valve manufacturer performs the API 598 testing, issues the report, and applies the MSS SP-25 markings as the valve leaves the works. A stockist such as NF Teguh issues neither: its job is to obtain the documents with the goods and pass them through against your order lines — which is why documents are requested on the order, where the counter can secure them from the source, not after delivery, when the source has moved on.
Paperwork required on the purchase order costs one line of text. Paperwork chased after delivery costs weeks — and sometimes cannot be produced at all.
That asymmetry is the whole economics of this memo. Nothing in the chain is expensive at origination time; everything is expensive, or impossible, in retrospect.
Wording to put on the purchase order
The order wording does not need legal drafting; it needs the document, the standard and the scope named per line. Three patterns cover most cases. For material: “EN 10204 type 3.1 inspection certificates required for pressure-retaining parts.” For testing: “API 598 test reports required, referenced to valve serial numbers.” For identity: “Valves to be marked in accordance with MSS SP-25; nameplate details to match certificates supplied.” Add a delivery condition that does quiet work: “documents to be supplied with the goods” — so certificate and crate cannot arrive a month apart.
Write the requirement on the enquiry as well as the order, so it is priced in from the first quotation — the route those documents travel through is on how ordering works. And keep scope honest: a utility drain valve carrying 3.2 certification is money spent on paper the service never asked for. The companion guide, specifying industrial valves, covers the rest of the order line.
Where to go deeper
Each document above has a memo behind it, and the pattern-selection memos below carry the same discipline into the hardware itself — read the one your current order is stuck on.
3.1 vs 3.2 certificates
What procurement actually needs, and when 3.2 earns its cost.
MEMOAPI 598 testing explained
What a shell and seat test report shows, line by line.
MEMOReading a nameplate
MSS SP-25 marking explained, field by field.
MEMOTrunnion or floating
Choosing a ball valve mounting as size and class climb.
MEMOWafer, lug or flanged
Choosing a butterfly valve body for the job it must do.
MEMOCheck valve types
Swing, dual-plate and piston — where each pattern fits.
Standards named in this memo are published reference data — confirm against the current edition; your purchase order governs. Questions: the counter.