Pressure test witnessing
Shell, backseat, high-pressure seat and low-pressure air seat tests to API 598, API 6D, EN 12266-1 or ISO 5208 as named in your PO.
What is made in Wenzhou
Wenzhou is China’s largest industrial valve cluster. Workshops around Oubei (Yongjia County), Longwan and Rui’an typically make gate, globe, check, ball and butterfly valves, and petrochemical valves for export. It is the main area where buyers ask us to witness API 598 and API 6D tests.
- Gate, globe and check valves (cast and forged)
- Floating and trunnion ball valves
- Butterfly valves
- Petrochemical and pipeline valves
We do not publish or recommend factory names. We inspect the factory you have chosen, against your PO.
At a glance
- Base
- Ningbo High-tech Zone, Zhejiang
- Inspector
- Kevin Lyu (吕中国), independent valve & machinery inspector
- Rate
- USD 220–260 per man-day plus travel, quoted in writing first
- Report
- English, normally within 24 hours of the visit
Inspection services in Wenzhou
The factory performs pressure tests on its own bench; we witness, time and record them.
Pre-shipment inspection
AQL sampling, markings, dimensions, documents and packing, when 100% finished and at least 80% packed.
DUPRO
Castings, heat numbers and critical dimensions while bodies are still unpainted.
Factory audit
Capability, test bench, gauge calibration and MTC handling before a first order.
Getting to Wenzhou from Ningbo
Indicative only. Road distances and times are estimates; train times are the fastest scheduled services.
| Location | Road distance | Driving | High-speed rail |
|---|---|---|---|
| Wenzhou — Oubei (Yongjia) | ~292 km | ~4.5 h | fastest ~1 h 38 min to Wenzhou South |
| Wenzhou — Longwan / Rui’an | ~300–330 km | ~4.6–5 h | via Wenzhou South |
For a single PSI we usually take an early high-speed train to Wenzhou South and transfer by road to the factory, returning the same day. Larger jobs, long test-witness schedules or several factories on consecutive days are planned with an overnight stay. Either way, the travel cost — actual cost or a fixed surcharge — is quoted in writing before you confirm.
See all coverage and travel times, the Zhejiang valve clusters buyer’s map and pricing.
We report facts from the samples inspected; we do not issue product certificates or accreditation marks.
Last updated: 2026-11-14