What Is a Valve Data Sheet? VDS Explained
A Valve Data Sheet (VDS) is a standardized engineering document that specifies the technical requirements for each valve in a piping system. It contains the design conditions, material specifications, end connections, actuator requirements, and testing criteria that manufacturers must meet. The VDS is the primary document used for valve procurement, manufacturing, and inspection in EPC projects.
Every valve on a P&ID is linked to a VDS through its tag number. A project with 500 valves may have 80-120 unique VDS documents, each covering a specific valve type, size, pressure class, and service condition.
VDS Contents
| Section | Information Specified |
|---|---|
| Tag number | Unique valve identifier (e.g., XV-1001, PCV-2005) |
| Service | Fluid type, corrosivity, H2S content, solid particles |
| Design pressure | Maximum allowable working pressure (e.g., 42 barg) |
| Design temperature | Max and min operating temperatures (e.g., -29 to 200 deg C) |
| Valve type | Gate, globe, ball, butterfly, check, plug |
| Size | NPS or DN (e.g., 6” / DN 150) |
| Pressure class | ASME class 150, 300, 600, 900, 1500, 2500 |
| Body material | ASTM grade (e.g., A216 WCB, A351 CF8M, A352 LCC) |
| Trim material | Seat, stem, disc materials and hardness |
| End connections | Flanged RF, flanged RTJ, butt-weld, socket weld, threaded |
| Actuator | Manual, pneumatic, electric, hydraulic; fail position (FC/FO/FLP) |
| Applicable standards | API 600, API 6D, API 608, BS 1868, ASME B16.34 |
| Testing requirements | API 598, hydrostatic shell and seat test pressures |
| Special requirements | NACE MR0175, fire-safe per API 607, fugitive emission per ISO 15848 |
Who Prepares the VDS
The piping/materials engineer creates the VDS using process data from the P&ID, line list, and pipe class. Instrument engineers add control valve requirements (Cv calculations, rangeability, positioner specs). The VDS goes through a design review before issue to procurement.
| Discipline | VDS Input |
|---|---|
| Process engineering | Operating conditions, fluid properties, Cv sizing |
| Piping engineering | Valve type, size, class, end connections, pipe class reference |
| Materials/corrosion | Body and trim material selection, NACE compliance |
| Instrument engineering | Actuator type, fail position, control signal, accessories |
| Project specifications | Company-specific valve requirements, approved manufacturers |
VDS in the Procurement Cycle
The VDS is attached to the RFQ package alongside the valve summary (a tabulation listing all valves by tag number, type, size, and class). Vendors quote against the VDS and submit their proposals on vendor data sheets—returning the same form with their offered construction details filled in.
During technical bid evaluation, engineers compare the vendor-returned VDS against the project VDS line by line. Deviations—a different body material, a non-compliant seat material, or a missing NACE certification—must be formally accepted or rejected.
VDS vs Valve Specification
The VDS defines requirements for individual valves (or groups of identical valves). The valve specification is the overarching project document that sets general requirements: approved manufacturers, inspection levels, painting, tagging, and documentation. The VDS references the valve specification for these general requirements and adds tag-specific details.
| Document | Scope | Level of Detail |
|---|---|---|
| Valve specification | All project valves | General requirements, QA/QC, approved vendors |
| Valve data sheet (VDS) | Specific valve tag or group | Exact design conditions, materials, actuator, testing |
Accurate VDS documents prevent procurement errors, reduce manufacturing non-conformances, and ensure that every valve delivered to site matches the engineering design. For valve material specifications and testing requirements, see the detailed guides.
Leave a Comment
Have a question or feedback? Send us a message.