Industrial Ball Valve RFQ: Size, Class, Materials and Test Requirements
An industrial ball valve RFQ should describe the service, not just ask for “a ball valve”. A supplier such as carilovalves can only quote accurately when the buyer states the fluid, design pressure, design temperature, normal and maximum operating conditions, pipe size, valve type, end connection, material grade, seat/seal requirements, operation mode, testing and document requirements.
Start with design and operating conditions
| RFQ field | Example entry | Why it matters |
|---|---|---|
| Fluid | Natural gas, cooling water, solvent, steam, slurry or corrosive chemical. | Determines body, trim, seat and seal compatibility; final compatibility should be confirmed by the project engineer or material specialist. |
| Design pressure and design temperature | The pressure and temperature basis used for valve rating and specification. | Controls pressure class, pressure-temperature rating and material limits. |
| Normal and maximum operating conditions | Expected operating pressure/temperature plus upset or maximum values. | Helps the supplier check torque, seat selection, actuator sizing and service margin. |
| Line size and bore | NPS / DN, full bore or reduced bore. | Affects pressure drop, pigging and cost. |
| End connection | RF flange, RTJ, butt weld, threaded or socket weld. | Must match piping design and site installation practice. |
| Operation | Lever, gear, pneumatic, electric or hydraulic actuator. | Changes torque, space envelope, wiring and fail-safe logic. |
Choose the valve construction
Floating ball valves are common in smaller or moderate-pressure applications. Trunnion-mounted ball valves are often used for larger sizes or higher pressure because the ball is mechanically supported. Fully welded body valves may be chosen for buried or long-distance pipeline service where external leakage paths and maintenance access are major concerns. The RFQ should name the expected construction instead of leaving the supplier to guess.
Use standards carefully
API standards development procedures describe API standards as consensus-based documents. ASME B16.34 covers pressure-temperature ratings, dimensions, tolerances, materials, nondestructive examination requirements, testing and marking for flanged, threaded and welding end valves. A public API 6D addendum publicly describes specification categories such as design, manufacturing, materials, testing, marking, documentation and process controls for several valve types, including ball valves. A buyer should not write “API / ASME” as a slogan. The RFQ should state the exact standard, edition if required by the project, and whether the requirement is design, testing, marking, documentation or certification.
Teaching RFQ paragraph
The following example is only a teaching template. It is not complete enough for direct procurement until the missing project parameters, material grades, seat/seal compatibility and governing standard/edition are confirmed by engineering.
“Please quote two trunnion-mounted ball valves, NPS 8, Class 600, full bore, RF flanged ends, carbon steel body to the project-specified grade, stainless trim, seat/seal material confirmed for dry natural gas at the stated design and operating pressure/temperature range. Include datasheet, general arrangement drawing, material certificates, pressure test procedure, painting and packing details, delivery time, spare seat/seal kit option and any deviations from the requested standard.”
Ask for deviations in writing
- If the supplier proposes a reduced bore, ask for pressure drop impact.
- If the material grade or seat material changes, ask for engineering confirmation of pressure-temperature and media compatibility.
- If the delivery time depends on casting or forging availability, ask for the critical path.
- If certification is claimed, ask for the certificate scope and whether it applies to the quoted product.
- If actuator sizing is included, ask for torque basis and safety factor.
A clear RFQ prevents the wrong valve from being “technically close but commercially painful”. The best quotation is not the shortest one; it is the one that states the assumptions, standards, tests and exceptions clearly enough for engineering review.