Minimum RFQ Fields
| Data group | Minimum information | Missing-data risk |
|---|---|---|
| Fluid | Name, composition, phase, water, corrosive components, solids | Wrong body, trim, seat, seal, packing, or lubricant |
| Pressure | Normal, maximum operating, design, opening differential, closing differential | Wrong pressure rating or undersized actuator |
| Temperature | Normal range, design minimum and maximum, cleaning, ambient limits | Seat deformation, packing leakage, or excessive torque |
| Function | Isolation, ESD, blowdown, pigging, throttling, drain, bypass | Wrong bore, seat, actuator, or valve type |
| Sealing | Pressure direction, cavity relief, leakage rate, test method | Valve seals in the wrong direction or fails acceptance testing |
| Actuator | Minimum, normal, maximum supply; fail position; stroke time | Valve cannot complete the required movement |
| Testing | Test name, standard, medium, pressure, duration, percentage | Late price increase, retesting, or delivery delay |
| Documents | Drawings, BOM, torque, certificates, ITP, deviation list | Design differences remain hidden before production |
Standard and Edition
| Standard | Use in the RFQ |
|---|---|
| API Specification 6D | Pipeline and related piping valves within its scope |
| ISO 14313 | Requirements that supplement API 6D for applicable pipeline valves |
| API Standard 608 | Metal ball valves for petroleum, petrochemical, and industrial service within its scope |
| ASME B16.34 | Pressure-temperature ratings, materials, construction, examination, testing, and marking |
| API Standard 598 or ISO 5208 | Inspection, shell testing, and closure testing |
ASME B16.34 applies to new valve construction and covers pressure-temperature ratings, dimensions, materials, examination, testing, and marking for the valve types within its scope.[1]
API Specification 6D is in its 25th edition. API lists Addenda 1, 2, and 3 and Errata 1, 2, and 3 for that edition. State the exact contractual document set instead of writing only “latest edition.”[2]
ISO 14313:2025 supplements API Specification 6D, 25th edition, for the pipeline valves covered by its scope.[3]
API Standard 608, 7th edition, became effective on October 2, 2025. Its size, class, material, construction, and end-connection limits must be checked before it is specified.[4]
API lists API Standard 598, 11th edition, as the current published edition of its valve inspection and testing standard.[5]
ISO 5208:2015 covers pressure-boundary integrity, closure tightness, and the strength of the closing mechanism. Use it with the selected valve product standard.[6]
Use this document order when requirements conflict:
- Purchase order
- Approved valve data sheet
- Project valve specification
- Piping material specification
- Inspection and test plan
- Referenced valve standard
- Manufacturer’s standard
Fluid and Contaminants
| Fluid item | RFQ entry | Parts affected |
|---|---|---|
| Main fluid | Name and concentration range | All wetted parts |
| Fluid phase | Liquid, gas, vapor, slurry, or two-phase | Seats, cavity, flow path, actuator torque |
| H₂S and CO₂ | Concentration or partial pressure | Body, ball, stem, seats, bolting, welds |
| Water | Water content and possible free water | Corrosion and sour-service assessment |
| Chlorides | Normal and maximum concentration | Stainless steel, duplex, overlay, springs, fittings |
| Viscosity | Value at minimum and maximum temperature | Operating torque and flow loss |
| Vapor pressure | Value at operating temperature | Flashing and two-phase flow review |
| Treatment chemicals | Methanol, glycol, inhibitor, solvent, detergent | Seats, O-rings, packing, gaskets, lubricant |
| Temporary fluids | Steam, nitrogen, flushing water, cleaning chemicals | Temperature and chemical compatibility |
Do not write only “natural gas,” “produced water,” “amine,” or “seawater.” Material selection changes when water, H₂S, chlorides, solvents, oxygen, or solid particles are added to the same base fluid.
For side-entry valves, compare the body, ball, stem, seat ring, overlay, bolting, and soft-part materials against the fluid data in the side-entry ball valve material guide.
Operating Cases
| Case | Valve position | Upstream pressure | Downstream pressure | Temperature | Must operate? |
|---|---|---|---|---|---|
| Normal operation | Open or closed | Normal value | Normal value | Normal range | State requirement |
| Start-up | State position | Start-up value | Start-up value | Start-up value | Yes or no |
| Emergency shutdown | Moving to fail position | Maximum possible | Minimum possible | Emergency value | Yes |
| Depressurization | Open, closed, or moving | Falling | Falling | Minimum expected | State requirement |
| Steam-out | Open, closed, or cycling | Cleaning pressure | Cleaning pressure | Steam temperature | State requirement |
| Long shutdown | Open or closed | Residual pressure | Residual pressure | Ambient or maintained | Breakaway after storage |
Use the worst value from each case for material limits, seat design, torque, actuator sizing, cavity relief, and testing. The highest pressure, highest temperature, and highest operating differential pressure may come from three different cases.
Pressure and Temperature
| Pressure item | Illustrative value |
|---|---|
| Normal operating pressure | 55–78 barg |
| Design pressure | 92 barg |
| Downstream pressure during normal closing | 65 barg |
| Normal closing differential pressure | 13 bar |
| Downstream pressure during emergency closing | 0 barg |
| Emergency closing differential pressure | 78 bar |
The emergency closing differential pressure in this example is six times the normal closing value. Valve torque and actuator sizing must use the 78-bar case when emergency closure is required.
| Temperature item | Illustrative value | Required check |
|---|---|---|
| Normal operating range | 15–80°C | Continuous material and torque limits |
| Minimum design temperature | −29°C | Body impact properties and soft-part flexibility |
| Maximum design temperature | 100°C | Body and seat pressure-temperature ratings |
| Steam-out condition | 180°C at 3 barg | Seat, packing, gasket, lubricant, and valve position |
| Minimum ambient temperature | −10°C | Actuator, accessories, coating, and lubricant |
| Maximum ambient temperature | 50°C | Actuator seals, solenoid, switches, and electronics |
If the valve is exposed to 180°C steam, state whether it is pressurized, whether it must operate, how long the condition lasts, and whether the normal soft seats remain installed.
ISO 28921-1:2022 covers applicable low-temperature and cryogenic isolation valves with design temperatures from −50°C to −196°C.[7]
For LNG, liquid nitrogen, liquid oxygen, or other very cold fluids, state the minimum temperature, bonnet extension, insulation thickness, packing position, test temperature, cold leakage limit, and cold torque. The available construction can be checked against the forged cryogenic ball valve range.
Solids, Flow, and Cycling
| Solid item | Illustrative RFQ entry |
|---|---|
| Material | Rust and sand |
| Normal particle size | 50–150 μm |
| Maximum particle size | 300 μm |
| Normal concentration | 100 mg/L |
| Upset concentration | 500 mg/L |
| Valve operation | Must close while particles are present |
| Commissioning flush | Clean water before normal operation |
Do not use the example values as a universal soft-seat or metal-seat limit. Seat choice also depends on particle hardness, shape, velocity, pressure drop, cycling, and permitted leakage.
| Valve duty | Additional RFQ data |
|---|---|
| Isolation | Shutoff direction, differential pressure, leakage limit |
| Emergency shutdown | Worst differential pressure, fail position, stroke time |
| Blowdown | Flow, pressure drop, temperature drop, noise, discharge time |
| Pigging | Minimum clear bore, pig size, internal steps, valve position |
| Partial opening | Flow, upstream and downstream pressure, opening angle, duration |
| Frequent cycling | Cycles per hour, day, and year; pressure during each cycle |
| Long static period | Maximum time without movement and required breakaway torque |
For heat, hard particles, or frequent severe operation, compare the required leakage and service limits with the forged metal-seated ball valve. Clean service requiring tighter shutoff may use a soft-seated trunnion ball valve when its pressure, temperature, and chemical limits are suitable.
Valve Construction
| Design choice | Use when | RFQ data needed |
|---|---|---|
| Floating ball | Smaller sizes and duties within the manufacturer’s pressure and torque limits | Size, class, differential pressure, torque, seat material |
| Trunnion-mounted ball | Larger size, higher pressure, supported ball, defined seat arrangement | SPE/DPE setup, cavity relief, drain, vent, torque |
| Side entry | Standard pipeline or process installation with line removal for major service | Body pieces, bolting, maintenance clearance |
| Top entry | Internal maintenance is required without removing the body from the line | Access space and maintenance procedure |
| Fully welded | Buried or long-term pipeline service with no body joint | Burial, coating, welding, stem extension, repair plan |
| Full bore | Low pressure loss or pigging is required | Minimum finished bore and pipe internal diameter |
| Reduced bore | Smaller flow area is acceptable and pigging is not required | Permitted pressure loss and velocity |
Use the actual size, pressure, torque, and maintenance requirement when comparing floating and trunnion-mounted ball valves.
State whether the valve needs:
- Blowout-resistant stem
- Antistatic connection
- Locking device
- Mechanical travel stops
- Drain and vent connections
- Seat or stem sealant injection
- Lifting lugs or support feet
- Stem extension
- Marked installation direction
Ends and Bore
| Connection | RFQ fields |
|---|---|
| Flanged | Standard, class, facing, finish, drilling, face-to-face, gasket, bolting |
| Butt weld | Pipe OD, wall thickness, grade, corrosion allowance, bevel, root face, taper |
| Socket weld | Socket dimensions, pipe size, material, welding and examination requirements |
| Threaded | Thread standard, size, pressure limit, sealant restriction |
For butt-weld valves, also state:
- Maximum internal mismatch
- Field-welding procedure
- Post-weld heat-treatment cycle
- Maximum permitted temperature at the seats and packing
- Need for factory-welded pup pieces
- Tests repeated after field welding
For pigging, give the smallest permitted finished opening through the end connection, seat area, and ball port. “Full bore” does not prove that the selected pig can pass.
Materials and Soft Parts
| Part | Information required |
|---|---|
| Body and closure | Material specification, grade, heat treatment, impact requirements |
| Ball and stem | Base material, overlay or plating, hardness, surface finish |
| Seat rings | Material, hardness, spring arrangement, pressure direction |
| Seat inserts | Exact polymer and filler, pressure-temperature limit |
| O-rings and seals | Exact elastomer, rapid gas decompression requirement |
| Packing and gaskets | Material, temperature range, fire and emission requirement |
| Bolting | Material, grade, coating, temperature and sour-service limit |
| Springs and fittings | Material, corrosion resistance, heat-number traceability |
ISO 15156-1:2020 provides general principles for selecting cracking-resistant metallic materials in H₂S-containing oil and gas production and natural-gas treatment environments.[8]
ISO 17945:2015 applies to metallic materials used in sour petroleum-refining environments where sulfide stress cracking can affect pressure containment or equipment operation.[9]
Replace “NACE compliant” with the applicable standard, water phase, H₂S level or partial pressure, temperature, pH, chloride content, material grade, and hardness limit.
| Soft-part group | Possible materials | Checks required |
|---|---|---|
| Seat inserts | PTFE, modified PTFE, reinforced PTFE, PCTFE, PEEK, UHMWPE, nylon | Creep, extrusion, wear, chemical compatibility |
| Elastomer seals | FKM, FFKM, HNBR, NBR, EPDM | Swelling, decompression damage, low-temperature hardness |
| Packing and gaskets | Flexible graphite, PTFE-based packing, metal-reinforced gaskets | Temperature, fire backup, emissions, adjustment limits |
Seat Direction and Leakage
| Question | Required answer |
|---|---|
| Which seat seals normal upstream pressure? | State upstream side and seat type |
| Must the valve seal with reversed pressure? | Yes or no, with test pressure and leakage limit |
| Can the body cavity be vented with both ends pressurized? | State operating sequence and permitted leakage |
| Where does excess cavity pressure go? | Upstream line, downstream line, or external relief device |
An SPE seat can provide an internal cavity-pressure relief path toward the lower-pressure line side. A DPE seat can seal against pressure from the line or body cavity and may require a separate relief device.
Use the sectional drawing to verify the seat springs, SPE/DPE direction, vents, drains, and relief path. The layouts are shown in the trunnion valve DBB structure. For compact instrument connections, check the same pressure and bleed details when specifying a DBB compact manifold.
| Leakage-test field | Required entry |
|---|---|
| Standard | API 598, ISO 5208, API 6D, or project requirement |
| Acceptance | Leakage rate or leakage class |
| Medium | Water, air, nitrogen, helium, or specified fluid |
| Pressure | Exact pressure or standard clause |
| Duration | Exact hold time or standard clause |
| Direction | Upstream, downstream, or both directions |
| Cavity condition | Vented, drained, isolated, or monitored |
| Quantity | Every valve or stated sample percentage |
Actuator Sizing
| Actuator input | Illustrative value |
|---|---|
| Minimum air supply | 4.5 barg |
| Normal air supply | 7 barg |
| Maximum air supply | 8 barg |
| Fail position | Fail closed |
| Emergency closing time | 8–12 seconds |
| Maximum closing differential pressure | 78 bar |
| Full operating cycles | 4 per year |
| Partial-stroke tests | 12 per year |
Request these six valve-torque values:
- Break-to-open torque
- Running-to-open torque
- End-to-open torque
- Break-to-close torque
- Running-to-close torque
- End-to-close torque
Apply the project sizing factor to the highest required valve torque. Compare the result with actuator output at the minimum supply pressure through the complete stroke.
At maximum supply pressure, actuator output must remain below:
- Maximum allowable stem torque
- Ball drive and key limit
- Coupling limit
- Gearbox limit
- Bracket and mounting-kit limit
ISO 12490:2011 covers mechanical integrity and sizing of electric, pneumatic, and hydraulic actuators and mounting kits used on pipeline valves manufactured under ISO 14313 and API 6D.[10]
Site and Installation
| Installation | RFQ fields |
|---|---|
| Outdoor | Ambient range, rain, UV, dust, ingress protection, coating |
| Coastal or offshore | Salt exposure, marine coating, external fasteners, tubing |
| Buried | Depth, soil, groundwater, coating, cathodic protection, stem extension |
| Insulated | Insulation thickness, stem extension, packing position |
| Heat traced | Tracing temperature and maximum local valve temperature |
| Flooded or submerged | Water depth, duration, sealing, breather and enclosure rating |
| Elevated platform | Stem height, access, actuator support, lifting limit |
Also state the stem orientation, flow direction, maintenance clearance, external piping loads, actuator weight, lifting points, and support arrangement.
Directive 2014/68/EU applies within its scope to pressure equipment and assemblies with a maximum allowable pressure above 0.5 bar. Check its exclusions and conformity route for equipment placed on the European Union market.[11]
Tests and Inspection
| Test type | Meaning | RFQ entry |
|---|---|---|
| Routine production test | Test applied to production valves | Standard, percentage, acceptance |
| Type test | Qualification of a representative design | Certificate and qualification range |
| Order-specific test | Additional purchaser requirement | Procedure, quantity, cost, schedule |
| Witnessed test | Test attended by purchaser or inspector | H/W/R point and notice period |
| Inspection or test | Illustrative scope |
|---|---|
| Hydrostatic shell test | 100% of valves |
| Bidirectional seat test | 100% of valves |
| Low-pressure gas closure test | 100% of valves |
| Functional cycle test | 100% of automated assemblies |
| PMI | Every listed alloy part on every valve |
| Radiographic examination | Specified casting or weld areas |
| Purchaser witness | First valve and selected additional units |
The example scope is not a universal requirement. Set the percentage from the product standard, service risk, material, manufacturing method, and project specification.
Final pressure and closure tests should use the final body bolting, gaskets, packing, seats, and seals. State which tests must be repeated after repair, adjustment, disassembly, or replacement.
Each test report should record:
- Valve serial number
- Test medium
- Pressure and duration
- Temperature
- Pressure direction
- Cavity condition
- Instrument IDs and calibration status
- Measured leakage or pass/fail result
- Inspector and date
Put hold points, witness points, review points, test percentages, and release documents into the valve inspection and test plan.
Special Tests
| Requirement | RFQ fields |
|---|---|
| Fire test | Standard, edition, certificate, tested design, qualification range |
| Fugitive emissions | Standard, leakage class, temperature, cycles, test gas, production percentage |
| Cryogenic test | Temperature, medium, cooling, soak time, cycles, leakage, cold torque |
| PMI | Included parts, test method, every valve or sampling |
| Hardness | Parts, locations, maximum value, test method |
| Impact test | Material, temperature, specimen and acceptance |
| NDE | Method, part, area, stage, percentage, acceptance |
| Test-water control | Chloride, inhibitor, draining, drying, preservation |
API lists API Standard 607, 8th edition, as the current published fire-test standard for quarter-turn valves and valves equipped with nonmetallic seats within its scope.[12]
ISO 15848-1:2015 covers classification and qualification procedures for valve fugitive-emission type testing.[13]
ISO 15848-2:2015 covers production acceptance testing where fugitive-emission requirements are specified.[14]
API lists API Standard 641, 2nd edition, as the current published API type-test standard for fugitive emissions from quarter-turn valves within its scope.[15]
Do not accept “fire-safe design” or “low-emission packing” as proof. Match the certificate to the offered manufacturer, product family, body design, size, class, seat, packing, gasket, temperature, and cycle range.
The difference between type qualification and production acceptance is covered in the fugitive-emission testing guide.
Documents and Deviations
| Document with quotation | What to check |
|---|---|
| Completed data sheet | No blank process, pressure, temperature, or test fields |
| General arrangement drawing | Dimensions, weight, ends, operator, orientation |
| Cross-sectional drawing | Materials, seats, springs, seals, vents, drains, relief path |
| Bill of materials | Exact material grades for every important part |
| Pressure-temperature limits | Body, seats, seals, packing, gaskets |
| Torque data | Six torque points, pressure, temperature, safety factor |
| Actuator calculation | Minimum supply, full-stroke output, maximum output, MAST |
| Type-test certificates | Qualification range matches offered valve |
| Preliminary ITP | Tests, percentages, H/W/R points, records |
| Deviation list | Every exception and its technical, cost, and schedule effect |
| RFQ requirement | Supplier offer | Status | Effect |
|---|---|---|---|
| PEEK seat | Reinforced PTFE | Deviation | Different temperature and differential-pressure limit |
| Gas-seat test on every valve | Sample testing | Deviation | Reduced inspection scope |
| Maximum 8-second closing time | 8–10 seconds | Deviation | Process and safety review required |
| PMI on all listed alloy parts | Body and ball only | Partial compliance | Stem, seats, bolting, and fittings excluded |
| Specified emission qualification | Low-emission packing only | Not compliant | No matching type-test evidence |
Question these phrases before acceptance:
- Suitable for service
- Vendor standard
- Fire-safe design
- NACE compliant
- Zero leakage
- Bubble-tight
- Full bore
- Low-emission packing
- 100% NDE
- Cryogenic design
- Standard testing included
Complete RFQ Example
Quantity: 4
Valve: NPS 8, ASME Class 600, full-bore, trunnion-mounted ball valve
Product standard: API Specification 6D, 25th edition, including the addenda and errata listed in the purchase specification
End connection: ASME B16.5 Class 600 raised-face flanges
Service: Wet natural gas; full composition attached
Normal operating pressure: 55–78 barg
Design pressure: 92 barg
Normal operating temperature: 15–80°C
Minimum design temperature: −29°C
Maximum design temperature: 100°C
Steam-out condition: 180°C at 3 barg, valve fully open, no operation required during steam-out
Maximum normal-closing differential pressure: 13 bar
Maximum emergency-closing differential pressure: 78 bar
Solids: Rust and sand; normal particle size 50–150 μm; maximum 300 μm; normal concentration 100 mg/L; upset concentration 500 mg/L
Function: Emergency isolation, normally open
Cycles: 4 full cycles and 12 partial-stroke tests per year
Closing time: 8–12 seconds at the emergency condition
Seat arrangement: SPE/SPE. Each seat shall seal pressure from its line side. Excess body-cavity pressure shall relieve toward the lower-pressure line side.
Closure acceptance: ISO 5208 Rate A for the selected soft-seat design, tested in both directions under the approved procedure
Body: ASTM A105N, subject to pressure-temperature and impact-property verification
Ball and stem: Exact corrosion-resistant grades stated in the supplier BOM
Seats and seals: Exact materials selected from the attached fluid, temperature, pressure, solids, and decompression data
Actuator: Pneumatic spring return, fail closed
Air supply: 4.5 barg minimum, 7 barg normal, 8 barg maximum
Actuator sizing: Based on 78 bar emergency differential pressure, minimum air supply, highest service torque, and project sizing factor. Maximum output shall remain below MAST and all drive-part limits.
Site: Outdoor coastal installation; ambient temperature −10°C to 50°C
Routine tests: Shell, bidirectional seat, low-pressure gas closure, cavity relief, functional, stroke-time, torque, antistatic, drain, and vent tests
Test percentage: Shell, seat, gas closure, and functional tests on 100% of valves; PMI on every listed alloy part; NDE according to the approved component list
Bid documents: Completed data sheet, GA drawing, cross-section, BOM, pressure-temperature limits, six torque values, MAST, actuator calculation, certificates, preliminary ITP, and deviation list
Bid rule: List every assumption, exclusion, alternative, and deviation. Silence shall not be treated as compliance.
Finally
Do not release a ball valve order until ten items agree: fluid data, operating cases, five pressure values, design and temporary temperatures, seat direction, leakage test, six torque values, actuator output, material list, and test scope. In the example above, emergency differential pressure rises from 13 bar to 78 bar, so sizing from normal operation alone would use only one-sixth of the required pressure case. Check the data sheet against the cross-section, BOM, torque sheet, actuator calculation, ITP, and certificates. Resolve every mismatch and deviation in writing before material purchasing or machining begins.
