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Technical Parameters of Wafer Type Valves
| Parameter | Typical Specification |
|---|---|
| Design | Wafer, with centring holes or lugs; concentric (resilient seated) or double offset |
| Body material | CF8, CF8M, CF3M (A351); ductile iron with stainless disc on request |
| Disc material | 304, 316L, duplex, PTFE-coated or rubber-lined disc |
| Stem material | 304, 316, 17-4PH, 2205 duplex |
| Seat material | EPDM, NBR, FKM (Viton), silicone, PTFE, RPTFE, metal |
| Size range | DN40 to DN600 (1.5 inch to 24 inch) |
| Pressure rating | PN10, PN16, Class 150 (about 10 to 16 bar), double offset higher |
| Working temperature | -10 °C to +120 °C EPDM; -20 °C to +180 °C PTFE; higher with metal seat |
| Flange compatibility | ASME B16.5 Class 150, EN 1092-1 PN10 / PN16, JIS 10K, DIN |
| Face-to-face length | EN 558 Series 20, API 609, ISO 5752 |
| Top flange | ISO 5211 for actuators, with square or double-D stem drive |
Seat selection guide
| Seat | Best For | Avoid |
|---|---|---|
| EPDM | Water, steam to about 120 °C, cleaning agents, many chemicals | Mineral oils and fats |
| NBR | Oils, fuels, compressed air | Strong acids, ozone |
| FKM | Oils, many acids, higher temperature | Steam, strong alkalis |
| PTFE / RPTFE | Aggressive chemicals, wide temperature range | Highly abrasive media |
| Silicone | Food and pharmaceutical, neutral media | Steam, abrasive media |
Match the flange. Disc travel needs clearance, and some flange types, such as thick-lined pipe, weld neck flanges with a small bore or schedule 80 pipe, can touch the disc as it opens. Please tell us the pipe schedule and flange type so we can confirm there is enough space.
Torque and sizing note: concentric butterfly valves are sized by flow and differential pressure, but the torque value is what decides the actuator. We supply torque tables for each seat material and pressure, so you can select a suitable actuator and avoid undersizing, which is a common cause of incomplete closing.
Wafer Valve Range and System Supply
Wafer valves are often combined with other products to complete a flanged system. We supply them with the flanges, gaskets and bolts that go with them, and with the actuators and accessories that automate them. The table below lists the wafer products used most often.
| Product | Size Range | Typical Use |
|---|---|---|
| Wafer butterfly valve, lever operated | DN40 to DN200 | Water, HVAC, general fluids |
| Wafer butterfly valve, gear operated | DN200 to DN600 | Large lines, cooling water, process |
| Wafer butterfly valve, pneumatic actuated | DN40 to DN600 | Automated process lines |
| Wafer butterfly valve, electric actuated | DN40 to DN600 | Remote control, building automation |
| Wafer dual-plate check valve | DN40 to DN600 | Pump discharge, backflow prevention |
| Wafer single-disc check valve | DN15 to DN300 | Compact non-return, small lines |
| Wafer strainer and spacer | DN40 to DN300 | Protection of equipment, spacing |
| Flanges, gaskets, studs and nuts | DN15 to DN600 | Complete installation sets |
Where wafer valves fit best
- Space-limited installations: skid frames, plant rooms and ship machinery spaces.
- Cost-sensitive projects: lower weight and material cost than flanged body valves.
- Frequent operation: quarter-turn operation is quick and needs low torque.
- General service: water, air, steam to moderate temperature, chemicals and food-grade media.
Where a wafer valve will be used at the end of a pipeline, a lug type or flanged valve is usually better, and we are happy to advise.
Buyer tip: list the flange standard, pressure class, pipe schedule, medium, temperature and operator for each valve in your inquiry. Spending a few minutes on this table makes the quotation faster and more accurate, and avoids problems such as a disc that touches the pipe bore or a seat that is not suitable for the medium.
Design and Flange Standards for Wafer Valves
A wafer valve is clamped between flanges, so it must match both the flange standard and the face-to-face standard of the system. The following references are those we use most often for wafer butterfly and wafer check valves.
| Area | Standard Reference |
|---|---|
| Butterfly valve design | API 609 (Category A), EN 593, MSS SP-67, ISO 5752 |
| Wafer check valve design | API 594, EN 12334 |
| Face-to-face length | EN 558 Series 20, ISO 5752 Basic Series 20, API 609 |
| Compatible flanges | ASME B16.5 Class 150, EN 1092-1 PN10 / PN16, JIS B2220 10K, DIN 2501 |
| Actuator mounting | ISO 5211 |
| Pressure-temperature ratings | ASME B16.34 (where applicable), EN 12516, manufacturer ratings for rubber seats |
| Body material | ASTM A351 CF8 / CF8M / CF3M, ASTM A182 where forged |
| Testing | API 598, EN 12266-1, ISO 5208 |
Rubber-seated valves and shutoff class: resilient seats give bubble-tight shutoff in both directions when new, which is generally tested under Rate A of ISO 5208 or EN 12266. Metal-seated and double offset valves have different leakage classes, so please specify the leakage requirement for your application.
If your project requires another standard, such as GOST or JIS dimensions, tell us in advance and we will check whether the valve can be supplied in that format.
Reference note: API 609 and EN 593 are the two main design standards for butterfly valves, and they differ in wall thickness rules, test procedures and marking. If your project calls for one of them, state it in the inquiry, so we select the right design and prepare the matching test documentation before production begins.
Certificates and Approvals for Wafer Valves
Wafer valves are used in water supply, building services, process plants and food factories, each with its own documentation requirements. We prepare a certificate package that fits the application and confirm the contents before production.
- Material certificate: EN 10204 3.1 for body, disc and stem, with chemical and mechanical data.
- Seat compliance documents: FDA and EU food contact statements for EPDM, silicone and PTFE seats, where required.
- Drinking water approvals: WRAS, NSF 61 or equivalent for selected EPDM seats, on request.
- Pressure test report: shell and seat test per API 598 or EN 12266-1.
- Torque report: operating torque values for actuator sizing.
- CE and PED: for qualifying models and sizes.
- Fire safe or anti-static design reports: for selected models.
- Quality management: ISO 9001 style procedures and batch records.
Match approvals to market: a building services contractor in Europe may need WRAS and CE, while a United States buyer may ask for NSF 61 and ASME-related documents. Tell us the country and application, and we will propose models and documents that fit.
Not all approvals apply to every size, so please confirm requirements early in the order process.
Audit tip: keep the seat compliance statement together with the material certificate for each shipment. Building services and water utility auditors often ask for both, and a matching set prevents delays when a project engineer asks for proof that the seat is approved for drinking water or food contact. We can add the lot number to each document so it is easy to match to the delivered goods, and send electronic copies before shipment.
Traceability for Body, Disc, Stem and Seat
A wafer butterfly valve contains a small number of key parts, and each one affects performance. The disc and stem decide strength and corrosion resistance, and the seat decides sealing and chemical compatibility. We trace all of them, so each valve has a clear record.
- Body casting: heat number, material grade and size are cast or stamped on each body.
- Disc and stem: bar and castings are received with certificates and checked by PMI before machining.
- Seat moulding: rubber compound batch, cure date and hardness are recorded for each seat lot.
- Assembly: the assembly sheet lists body heat number, disc lot and seat batch for each valve serial number.
- Testing: pressure test and torque test results are filed against the serial number.
- Packing: cartons are labelled with size, class, seat material and lot, matching the packing list.
| Part | Record | Why It Matters |
|---|---|---|
| Body | Heat number and certificate | Proof of grade and pressure integrity |
| Disc | Heat number, PMI result | Resistance to corrosion and pitting |
| Stem | Lot and mechanical properties | Strength and torque capacity |
| Seat | Compound batch, cure date, hardness | Sealing and chemical resistance |
| Valve | Serial number and test reports | Evidence for audit and warranty |
Seat compound records are especially useful, because rubber properties change with age. If a seat issue is reported, the batch record allows us to check the cure date and material and take action quickly.
Why seat records matter: rubber ages with time and temperature, so the cure date and compound batch tell you how long a seat has been in stock, and whether it comes from a controlled lot. If you hold valves in your warehouse for months, this record helps you plan rotation of stock and avoid fitting aged seats in important duties.
Testing Capability for Wafer Valves
Wafer valves are tested for shell strength, seat sealing and operating torque. In addition, we check the features that decide how well the valve fits between flanges, such as seat face width and body centring features.
| Test | Method | Frequency |
|---|---|---|
| Shell test | Hydrostatic at 1.5 times rated pressure | 100% of valves |
| Seat test | Hydrostatic at 1.1 times rated pressure in both directions where specified | 100% of valves |
| Low-pressure air test | Compressed air under water to detect bubbles | 100% of resilient-seated valves |
| Operating torque | Torque tester at the stem or actuator pad | Sampling, 100% for actuated valves |
| Dimension inspection | Face-to-face, flange face, centring holes, stem square | First article and sampling |
| Seat hardness test | Shore A durometer | Per seat lot |
| Disc and stem check | PMI and visual inspection | Incoming and sampling |
| Cycle test | Repeated open-close operation to check torque change | Type test or on request |
Torque matters for actuators. The torque needed to turn a butterfly valve depends on seat material, differential pressure, medium and temperature. We measure it and supply values with a safety factor, which helps you choose an actuator that is neither too weak nor wastefully large.
Witnessed tests are welcome, and we can send photos or videos of testing when you cannot attend in person.
Sealing in both directions: for isolation duty, we recommend specifying bidirectional shutoff, so that the seat is tested from both sides. Some buyers only test one direction, which can hide a weakness. We follow the test direction written in your specification and can run both directions on all valves when asked.
Frequently Asked Questions about Wafer Type Valves
Q: What is the difference between wafer and lug type?
A wafer valve has no bolt holes of its own and is held between flanges by long through-bolts. A lug valve has threaded lugs, so it can be bolted to each flange separately and can be used at the end of a pipeline.
Q: Can a wafer valve be used as an end-of-line valve?
Not safely. Removing the downstream flange would leave the valve unsupported and the seat and body under pressure. Use a lug type or flanged valve with a blind flange instead.
Q: Which flanges can a wafer valve fit?
The body is designed for a specific standard, such as PN10 / PN16 or Class 150, and many valves are dual-drilled to fit both. Please tell us the flange standard so we can confirm.
Q: Do I need extra gaskets with a wafer butterfly valve?
Usually not. The rubber seat extends over the valve faces and acts as a gasket. For PTFE seats or metal-seated valves, a flange gasket may still be recommended, and we will tell you.
Q: Will the disc touch the pipe when opening?
It can if the pipe bore is smaller than the disc travel, for example with heavy-walled pipe or lined pipe. Please give us the pipe schedule and flange type so we can check clearance.
Q: Can wafer valves handle steam?
Standard EPDM seats handle saturated steam to about 120 to 130 °C for short periods. For continuous steam or higher temperatures, a PTFE seat or double offset design is more suitable.
Q: How do I choose between lever and gear operation?
Lever operators are suitable for small sizes, usually up to DN150. Larger sizes use a gearbox for easier operation and better control of position.
MOQ and Pricing for Wafer Valves
Wafer valves are sold in many sizes and configurations, so we allow mixed-size orders to meet minimum quantities. Prices depend most on size, disc material and seat.
| Item | Typical Terms |
|---|---|
| Sample order | 1 to 3 pieces per model |
| Standard MOQ | 20 to 50 pieces per size for stock models; mixed sizes accepted |
| Actuated valves | Small quantities accepted; actuator brand and voltage to be specified |
| Custom disc or seat | 100 pieces or more, depending on tooling |
| Pricing basis | EXW, FOB Ningbo, CFR or CIF in USD |
| Quote validity | 30 days, adjusted for stainless steel price changes |
| Payment | 30% T/T deposit, 70% before shipment; L/C at sight for approved accounts |
What affects the price
- Size: weight and material cost rise quickly above DN200.
- Disc material: 316L, duplex and coated discs cost more than 304.
- Seat material: PTFE and FKM seats cost more than EPDM or NBR.
- Operator: gear, pneumatic and electric operators add significant cost.
- Documentation: special approvals and witnessed testing are extra.
Saving tip: for water and general service, an all-stainless body with a 304 disc and EPDM seat often gives the best value. Upgrade the disc or seat only where the medium requires it.
Ordering advice: for projects with many sizes, ask for a package quotation with mixed sizes, a common seat material and standard lever or gear operators. This reduces the number of variants, lowers unit price, and makes spare parts planning easier for the operations team after commissioning. A short spare list is available on request.
Lead Time, Customisation, Packaging and Trade Terms
Lead time and stock
Standard wafer butterfly valves in popular sizes can ship in 15 to 25 days. Actuated assemblies, special seats and large sizes usually need 30 to 50 days. We can ship partial lots if you need the urgent sizes first.
Customisation
We can customise flange drilling, centring features, disc material, seat material, stem material, operator, handle colour, actuator interface, coating and marking. We can also supply valves pre-mounted with actuators, solenoids and limit switches.
Packaging
- Valve packed with the disc slightly open, to avoid seat compression during transport
- Foam or carton protection on both faces to protect the seat
- Individual cartons for small sizes, and wooden cases or pallets for larger ones
- Labels with size, class, seat material and lot number
- Neutral packing or customer-branded packaging on request
Shipping and trade terms
| Term | Details |
|---|---|
| Incoterms | EXW, FOB Ningbo, CFR, CIF, DAP |
| Port | Ningbo-Zhoushan; Shanghai as an alternative |
| Transport | Sea freight, air freight for urgent items, express courier for samples |
| Documents | Invoice, packing list, bill of lading, origin certificate, material and test certificates |
Wafer valves are light and compact, so containers can be loaded efficiently, especially when combined with other stainless valves from our range.
Handling advice: do not store valves with the disc fully closed for a long time, as this can compress the seat. Keep them dry, away from direct sunlight and ozone sources, and fit them within a reasonable period. We include a one-page storage and installation note with each shipment on request.
