What a valve inspection covers
Most valve problems found at the factory are paperwork and traceability problems, not leaks. A body cast from a different heat, a certificate copied from another order, or a test held for half the required time will not show up on a photo report. Our inspectors check the documents against the parts in front of them, then watch the tests.
The inspection plan follows your PO and ITP. Where you do not have one, we propose an ITP based on API 598 or API 6D and the valve type, and you approve it before the first visit.
Valve types we inspect
Gate, globe and check valves to API 600 and API 602, floating and trunnion ball valves to API 6D and API 608, butterfly valves to API 609, plug valves, control valves and pressure safety valves. For control valves and safety valves we witness the functional tests and set-pressure tests specified in your order.
Where valves are made in China
The largest valve cluster is in Wenzhou and Yongjia in Zhejiang province. Shanghai, Suzhou, Tianjin and Shenyang also have major manufacturers of large-bore and high-pressure valves. Tell us the vendor’s address and we will confirm the nearest inspector.
Non-conformances we find most often
- Heat numbers stamped on the body do not match the material certificate.
- Shell test held for less than the minimum duration in API 598 for the valve size.
- Test gauge out of calibration or with a range too large for the test pressure.
- Casting repairs welded without an approved repair procedure or record.
- Seat leakage above the allowable rate for the test class.
- Hardness of trim not reported where the PO calls for NACE MR0175 compliance.
- Flange facing or surface finish different from the PO (RF vs RTJ, wrong roughness).
Questions buyers ask
What does a third-party inspector check during a valve pressure test?
The inspector confirms the test medium, test pressure and hold time against API 598 or API 6D, checks that the gauge is calibrated and correctly ranged, watches for shell leakage and records seat leakage for each closure test before signing the test report.
Can you perform PMI on valves before shipment?
Yes. We use handheld XRF analysers to verify the alloy of bodies, bonnets, stems and trim on stainless, duplex and alloy valves, and record the readings against the specified grade.
How long does a valve inspection take?
A final inspection of one batch at one factory is usually one inspector-day. Large orders, 100% witnessing or multiple test benches take longer. We confirm the man-days after reviewing your PO and inspection and test plan.
Do you review fire-safe and fugitive emission certificates?
We review the API 607, API 6FA or ISO 15848-1 type test certificates and check that the valve design, size and pressure class are covered. These are type tests, so they are not repeated for each order.