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Valve and Flange Specification Checklist
Confirm these points before the purchase order and the valve will fit the line, suit the fluid and pass inspection on arrival.
Valves are the most frequently mis-ordered item in industrial procurement
A valve can carry the correct size and the correct pressure class and still be rejected on arrival. The usual causes are a face-to-face dimension that does not match the gap in the line, a flange face type that does not match the mating flange, or a trim that does not suit the produced fluid.
Run through these points before issuing the purchase order. Each one takes seconds to confirm and each one has held up a project when it was assumed instead.
1. Size and rating
- Nominal size confirmed against the line, not the drawing revision
- Pressure class confirmed for the design pressure and temperature together
- Design temperature range including start-up and upset conditions
- Bore type confirmed as full or reduced
- Schedule and wall thickness of the mating pipe recorded
2. Connection and dimensions
- End connection type: flanged, butt weld, socket weld or threaded
- Flange face type: raised face, ring type joint or flat face
- Flange facing finish confirmed where specified
- Face-to-face dimension and the standard it follows
- Overall envelope checked against the available space, including insulation
- Bolting and gasket requirements listed with the valve
3. Materials and service
- Body and bonnet material specified
- Trim material selected for the actual produced fluid
- Sour service requirement confirmed and documented under NACE MR0175 where it applies
- Corrosion allowance and any coating or lining requirement
- Fire safe requirement stated where the service demands it
- Fugitive emission requirement stated where applicable
4. Operation
- Operator type: handwheel, lever, gear, or actuated
- Actuator type and supply, including failure position
- Orientation and access confirmed against the installation
- Locking, position indication and limit switch requirements
- Stem type confirmed as rising or non-rising
5. Testing and documentation
- Test standard and test pressures stated on the order
- Witnessed testing requirement and who witnesses it
- Material test reports required for the pressure boundary
- Certification package format agreed with the receiving quality department
- Marking and tagging requirements confirmed
- Preservation and export packing requirements included in the order
How to use this list
- Confirm each point against the installation rather than the last purchase order for a similar item.
- Where a data point is unknown, say so on the requisition. An identified gap is cheap and a wrong assumption is not.
- Send photographs of the existing installation with the requisition where a valve is being replaced.
Want us to check a line list against this?
Send your details and we will review the specification with you before anything is ordered.