Pilot-Operated Safety Valves: A Chinese Maker's ASME UV and NB Certification, Witnessed in the US
A Chinese maker's pilot-operated safety valve samples have passed capacity and performance testing witnessed by ASME and NBBI, earning UV and NB certification — the US market-access layer for pressure relief valves.
Lead
Pilot-operated safety valve samples from Wujiang Dongwu Machinery Co. (DWMC) have passed capacity and performance tests witnessed by ASME and the National Board of Boiler and Pressure Vessel Inspectors, earning ASME UV and NB certification, the company announced.
Facts
The tests. The witnessed testing covered set pressure, blowdown (reseat) pressure, discharge capacity and the discharge coefficient, with all stated indicators verified against ASME requirements. (Source: the company's announcement, carried by trade media, September–October 2026.)
The product class. Pilot-operated safety valves serve duties with high back pressure, high set pressure, high sealing requirements and large relieving capacity — the complex end of the safety-valve family. (Source: the same.)
The maker's record. The company previously obtained UV and NB certification for spring-loaded safety valves in liquid service, and last month extended the certificates' scope to gas and steam media after sampling tests. (Source: the company's own site.)
A note on timing. The certification was reported by trade media from 21 September, with continued industry coverage through October. (Sources: the trade reports.)
Where this connects on this site
- What a certification does and does not say about the valve's seat tightness: ISO 5208 Rate A: What a Valve Seat-Leakage Class Does and Does Not Promise
- The order the inputs are read in — function first, class second, material third: Valve Selection Guide: From Function to Class to Material
- The selector: industrialvalveselect.com
Sources
| # | Basis |
|---|---|
| 1 | The UV and NB certification of the maker's pilot-operated safety valves after ASME/NBBI-witnessed capacity and performance tests; the parameters covered (set pressure, reseat pressure, discharge capacity, discharge coefficient); the product class's duty profile; the earlier spring-loaded certificates and their scope extension to gas and steam — 中国控制阀网（来源：东吴机械）, 2026-09-22 — http://cs.chinacvw.com/News_Show.aspx?id=41341 ｜ 东吴机械官网（英文版） — https://en.w-va.com.cn/index.php?c=show&id=68 |
Note on sourcing. This item reports a manufacturer's certification announcement carried by trade media. We record the verifiable layer — the certification, the witnessed tests and the parameters covered. We do not rank or recommend suppliers.
What the source does not state
The reports do not state the valve models or sizes certified, the test pressures and capacities achieved, the certificate numbers, or the validity period.
Update note
This item is a dated record of a publicly reported certification. We append corrections rather than rewrite history; corrections are marked Correction with the date.