Valves and wellhead equipment control pressure and flow, so a hidden fault rarely stays small. It shows up as a leak, a failed commissioning test or an unplanned shutdown, and by then the equipment is installed, the schedule is tight and the supplier is thousands of kilometres away. For importers, EPC contractors and procurement teams buying from China and the rest of Asia, the cheapest moment to find a problem is before the order ships.
This guide explains what an independent inspection of valves and wellhead equipment covers, why each check matters, which defects turn up most often, and how to choose the right inspection stage for your order. It is based on the checklists our inspectors use on valve and wellhead equipment inspection projects.
Key Takeaways
- A valve that looks fine on the outside can still leak through the seat, stick halfway open or carry the wrong pressure rating, so each unit must be checked against your purchase order and test records.
- Each equipment type has its own checklist: gate, globe and check valves, ball and butterfly valves, wellhead and Christmas tree equipment, and actuators and accessories fail in different ways.
- Material certificates, dimensions, casting condition, pressure tests, operation, marking and packing are the core areas to verify before shipment.
- Most buyers combine two or more inspection stages across a production run, because material and casting problems are cheapest to fix before testing and painting.
Why Valves and Wellheads Need Their Own Checks
A quick visual check is not enough for pressure-containing equipment. Many of the risks sit inside the product or in the paperwork behind it: a body casting with porosity, a seat that does not seal, a stem that binds, or a pressure class or material that does not match the order. None of these is obvious when a crate is opened on site.
That is why each unit has to be checked against three things:
- Your purchase order: the type, size, pressure class and material you actually ordered.
- The referenced standard and approved datasheets and drawings: the dimensions and requirements your supplier agreed to meet.
- The test records: and, where the order requires it, the pressure and function tests witnessed by the inspector.
An on-site inspection does this at the factory, before the equipment is preserved, crated and shipped. If something is wrong, the supplier can still repair or replace it, and you are not negotiating after the goods have arrived.
Every Equipment Type Needs Its Own Checklist
A gate valve, a ball valve and a wellhead assembly are built differently and fail in different ways. A generic checklist misses things, so our inspectors work to the list that matches what you are buying.
Gate, globe and check valves
These cast and forged valves handle isolation, regulation and backflow prevention. The checks focus on body and bonnet casting quality, face-to-face and end connection dimensions, the condition of the seat, disc and stem, and shell and seat test results.
Ball and butterfly valves
These quarter-turn valves include floating and trunnion-mounted ball valves. Here the emphasis is on smooth operation across the full stroke, seat and seal condition, flange drilling and face finish, and pressure class and material marking.
Wellhead and Christmas tree equipment
This group covers wellheads, Christmas trees, spools and related flow-control equipment. Inspectors look at material certificates and traceability, dimensions and connection interfaces, pressure test records or witnessing, and marking, rating and nameplate data.
Actuators, gearboxes and accessories
Manual gear operators, actuators and valve accessories are part of the same order and need checking too. We check that the model and rating suit the valve, that operation and position indication work, that mounting, fasteners and wiring are correct, and that coating, marking and packing are acceptable.
What Inspectors Check and Why It Matters
Every inspection is set up against your purchase order, the referenced standard and the approved datasheets and drawings. A typical valve and wellhead checklist covers the following areas.
Material verification
Certificates are checked against heat numbers, the specified grade and the order. This matters because a wrong material is invisible to the eye but can make the equipment unsuitable for its duty. It also confirms that the paperwork belongs to the equipment in front of you.
Dimensions and end connections
Face-to-face dimensions, end connections, flange drilling and overall dimensions are compared with the datasheet. A valve that does not fit the pipework or mating flange causes delays on site.
Body and casting condition
Inspectors look for porosity, cracks, sand holes and repair marks on bodies and bonnets. These are the parts that contain pressure, so casting flaws deserve close attention.
Pressure testing
Shell and seat tests are witnessed, or the test records are reviewed, where the order requires it. A shell test shows whether the body holds pressure, and a seat test shows whether the valve seals when closed. Tell us what your specification calls for and we confirm what is possible at your supplier.
Operation, internals and trim
Valves should open and close smoothly over the full stroke, with any actuator or gear function checked. Where the design allows inspection, we also check the seat, disc, ball, stem and seal condition. Stiff or uneven operation is much easier to correct at the factory than in the field.
Marking, nameplate, coating and packing
Size, pressure class, material, serial number and standard should appear on every unit. Paint condition, port protectors, preservation and crating are checked as well, since heavy equipment can be damaged on the way to site even when it left the factory in good order.
Whether you need a one-off check or ongoing oversight across a valve package, the checklist is built around your purchase order and the standards it references.
Defects Found Before the Order Ships
These are the findings that most often turn into rejected equipment, failed commissioning tests or delays on site when nobody looks before shipment:
- Material or heat number that does not match the certificate
- Face-to-face or flange dimensions outside the datasheet
- Porosity, cracks or sand holes in the body or bonnet casting
- Seat leakage or a failed shell test
- Stem or gland packing leakage
- Stiff, incomplete or uneven operation over the stroke
- Wrong actuator, gearbox or accessory for the valve
- Missing or incorrect nameplate data and marking
- Missing port protectors, damaged coating or inadequate crating
Notice how many of these are documentation or specification mismatches rather than dramatic failures. A wrong heat number or missing nameplate data may not stop a valve working, but it can stop the equipment being accepted at the receiving end. Catching these points early protects both the schedule and your relationship with the end user.
Which Inspection Stage Do You Need?
Material, casting and assembly problems are cheapest to fix before the equipment is tested and painted. Most buyers combine two or more stages across a production run.
If you are still choosing a supplier, a factory audit can help you assess the factory before you place the order. For related energy products, see our pages on pipe, fitting and flange inspection and pressure vessel and tank inspection.
What to Expect From a Third-Party Inspector
Independence matters when the inspector is checking equipment that your project depends on. The Inspection Company (TIC) was founded in 2007 with European management and works with more than 700 professional inspectors across Asia, with service coverage in more than 25 countries. TIC is an ISO/IEC 17020 accredited Type A inspection body, ISO 9001:2015 certified and ISO/IEC 27001 certified, and a member of Sedex and CNAS. Where sampling applies, inspectors use ISO 2859 (AQL) sampling.
In practice, this means:
- On-site inspection at your supplier's factory, set up against your purchase order, datasheets and referenced standards.
- A detailed, photo-backed report within 24 hours of the inspection, so you can approve, reject or ask for rework without losing days. A quick report is also provided the same day.
- Integrity controls: inspectors sign an anti-bribery contract after every inspection.
Before booking, send your purchase order or datasheet and tell us whether you need pressure tests witnessed or test records reviewed. Our team confirms the scope and what is possible at your supplier. Pricing is usually per man-day and depends on equipment type, quantity and location.
For a wider view of the sector, you can also browse our oil, gas and power equipment inspection and steel structure inspection pages.
Conclusion
Valves and wellhead equipment are buying decisions where hidden faults carry a real cost. Checking materials and certificates, dimensions, casting quality, pressure test results, operation, marking and packing at the factory is far cheaper than finding the same problems at commissioning. Choose the inspection stages that fit your order, build the checklist around your purchase order, and check that what ships matches what you ordered.
If you are planning an order of valves or wellhead equipment from Asia, our valve and wellhead inspection team is ready to help. Get a free quote or contact our team to book your inspection.
