How to read a valve datasheet

The first section of any datasheet identifies the product: manufacturer name and model reference, valve type, nominal size range, and the applicable standard (for example, EN 1074-1 for isolation valves, or API 6D for pipeline valves). Verify that the standard listed matches your project specification. A valve may comply with a similar but not identical standard and still not meet your project requirements.

Check the revision level and date. Datasheets are revised when products change, and an old datasheet revision may not reflect current production. If in doubt, request the current revision from the manufacturer or distributor.

The pressure-temperature (P-T) rating table is the most critical section of the datasheet. It gives the maximum allowable working pressure at each temperature, for each body material. Do not assume that the PN or Class rating on the nameplate applies at your operating temperature: ratings fall off as temperature rises, and the reduction can be significant above 100°C.

Check that the listed P-T table covers your operating temperature. If your medium is steam at 180°C or a hot fluid at 200°C, confirm that the valve has a rated pressure at that temperature that exceeds your design pressure with adequate margin. The standard design practice is to check at the highest operating temperature, not just at ambient.

Some datasheets list a single maximum operating pressure without a full P-T table. This is only acceptable if your application is genuinely at or near ambient temperature. For any elevated-temperature application, require the full P-T table.

A well-structured datasheet lists materials for each component: body, bonnet, gate or disc, stem, seat rings, packing, bolting and gaskets. Each should reference an EN, ASTM or equivalent material standard. "Stainless steel" is not a specification; "ASTM A351 Gr. CF8M" is.

Cross-check the listed materials against your fluid service. A carbon steel body rated for -20°C minimum design temperature, a bronze body in a system carrying ammonia, or a standard EPDM seat in a hydrocarbon service are all specification errors that a material cross-check will catch before the order is placed.

For valves going into drinking water, confirm that wetted materials carry the appropriate approval: WRAS in the UK, ACS in France, KTW in Germany, or the relevant national standard for your installation country.

The datasheet should specify the end connection standard: EN 1092-1 for European flanges (with face type: raised face, flat face, or tongue-and-groove), ASME B16.5 for American flanges, BSP or NPT for threaded ends. Confirm the face type matches your piping and gasket specification.

Face-to-face dimension is defined by EN 558 (for European valves) or ASME B16.10 (for American). Check that the face-to-face matches the standard series your pipe layout is designed around: a valve with a non-standard face-to-face will require custom spool pieces.

For wafer or lug-body valves, confirm the flange drilling dimensions match your pipe flange standard. Wafer butterfly valves drilled for EN 1092-1 PN10 will not fit an EN 1092-1 PN16 flange at large bores because the bolt circle changes between pressure classes.

The datasheet should identify the test standard applied to the valve: EN 12266-1 for industrial valves, API 598 for API-compliant valves, or equivalent. It should specify the test pressures for shell, seat and backseat tests, and the acceptable leakage rate for each.

For certifications required by your project (WRAS, fire-safe API 607 or API 6FA, DNV, ATEX, ABS, Bureau Veritas), confirm they are listed on the datasheet and request the certificate itself rather than relying on the datasheet notation. Certifications can lapse, be withdrawn, or apply only to specific product configurations.

Material traceability certificates (EN 10204 3.1 or 3.2) are separate from the product datasheet and are ordered at the time of purchase. The datasheet tells you what is available; the purchase order specifies what must be supplied.