The MECH threaded b.f.v tamper red, model XD311X, sizes 1″ – 2″ (DN25 – DN50), working pressure 175 PSI, UL / FM approved. An indicating control valve that opens and closes in a quarter turn through a gear operator that shows its position. This guide explains what it does and how it works, related models, technical data, the critical point in selection and installation, and common mistakes. For more, read the guide butterfly valves in fire protection.
At a glance
- A butterfly valve controls flow with a disc that rotates on a shaft inside the body: parallel to the flow when open, across it when closed.
- Sizes 1″ – 2″ (DN25 – DN50).
- Working pressure 175 PSI.
- Approvals: UL / FM.
- Connection: Thread ASME B1.20.1.
- Operating temperature: 0 – 80 °C.
Butterfly valve: what it does and how it works
A butterfly valve controls flow with a disc that rotates on a shaft inside the body: parallel to the flow when open, across it when closed. It is driven by a handwheel gear operator so it closes slowly, with an indicator showing its position (open / shut).
In fire systems it is used as a control valve on supplies, risers and valve rooms. Many models carry a supervisory (tamper) switch that signals the alarm panel when the valve is moved from fully open, because fire-protection standards require control valves to be supervised.
Related models
| Model | Product | Sizes | Pressure | Approvals |
|---|---|---|---|---|
| D371X | WAFER BUTTERFLY VALVE UL/FM RED | 2″ – 12″ | D371X-300 / D371X80 / D371X9-300: 300 ps | UL / FM |
| D381X | GROOVED BUTTERFLY VALVE UL/FM RED | 2″ – 12″ (DN50 – DN300) | D381X-300 / D381X80-300: 300 psig; D381X | UL / FM |
| XD371XG | WAFER BUTTERFLY VALVE NORMALLY CLOSED TAMPER SWITCH UL RED | 2″ – 12″ (DN50 – DN300) | 300 PSI | UL |
| XD381XC | GROOVED BUTTERFLY VALVE TAPPED BODY TAMPER SWITCH UL RED | 2″ – 12″ (DN50 – DN300) | 363 PSI | UL |
| XD381XG | GROOVED BUTTERFLY VALVE NORMALLY CLOSED TAMPER SWITCH UL RED | 2″ – 12″ (DN50 – DN300) | 363 PSI | UL |
| XD381X | GROOVED BUTTERFLY VALVE WITH TAMPER SWITCH UL/FM RED | 2″ – 12″ (DN50 – DN300) | 300 / 363 PSI | UL / FM / VdS |
| XD311X — this product | THREADED B.F.V TAMPER RED | 1″ – 2″ (DN25 – DN50) | 175 PSI | UL / FM |
| D81X4 | GROOVED B.F.V LEVER RED | 2″ – 12″ (DN50 – DN300) | 300 PSI | — |
| XD371X | WAFER B.F.V TAMPER UL/FM ANSI RED 3″ M: XD371X | 2″ – 12″ (DN50 – DN300) | 300 / 363 PSI | UL / FM / VdS |
Technical data
| Item | Specification |
|---|---|
| Connection ends | Thread ASME B1.20.1 |
| Working pressure | 175 PSI |
| Temperature | 0 – 80 °C |
| Coating | FBE — ANSI/AWWA C550 |
| Approvals | UL / FM |
| Sizes | 1″ – 2″ (DN25 – DN50) |
Dimensions for every size are in the size table at the top of the page.
Disc clearance when open
When open, the disc projects beyond the body on both sides. Fitted directly against a check valve, strainer or narrow fitting it may strike it and not open fully. Check the disc dimensions on the datasheet and add a spacer where needed.
Caution
Wire the supervisory switch to the alarm panel per NFPA 72 and the project drawings, and never leave the valve partly closed.
Installation steps
- Check the end type (wafer, grooved or threaded) and flange standard match the line.
- Open the valve slightly before fitting so the seat is not damaged, then install between flanges or with grooved couplings as applicable.
- Check disc clearance with adjacent fittings, then cycle the valve fully open and shut after installation.
- Wire the supervisory switch and test that the signal reaches the alarm panel.
Common mistakes
- Fitting it against a component the disc strikes.
- Tightening flange bolts with the valve fully shut, damaging the seat.
- Leaving the supervisory switch unwired or untested.
Files and ordering
On this page: Product datasheet, Installation & operation manual, MECH Fire Protection Valves Catalogue (UL/FM), Material Safety Data Sheet (MSDS). Add the product to your request list with size and quantity and we send a quotation, or build a submittal PDF for the consultant. Fu-Mech is the exclusive MECH agent in Saudi Arabia.
Frequently asked questions
Why is it gear-operated?
Fast closure causes water hammer, and standards require indicating control valves to close slowly. The gear operator slows the movement and shows the position.
What does the supervisory switch do?
It sends a supervisory signal to the alarm panel when the valve is moved from fully open, so any unintended closure is known. See pressure and supervisory switches.
What is the working pressure of model XD311X?
175 PSI per the product data. The pressure for each size or listed model is in the size table and datasheet.
What approvals does it carry?
UL / FM per the product data. Check the size and listed model in the approval listings, and see how to verify UL and FM approvals.
What end connection does it have?
Thread ASME B1.20.1. Choose the connection that matches the adjacent pipe and fittings.
References
- ASME B1.20.1 — Pipe Threads, General Purpose, Inch (NPT)
- AWWA C550 — Protective Interior Coatings for Valves and Hydrants
- MECH catalogue — Fire fighting valves
This guide is general information to help with selection. Figures come from the product data on this page and the MECH catalogue; final design is by the project’s approved designer to the applicable standards and the project specification.
