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Brand: Weflo
Weflo Fig. 5311 Double Interlocked Pre-Action Valve
Description
Double interlocked pre-action valve for water-sensitive areas
The Weflo Fig. 5311 is a pneumatically actuated, double interlocked pre-action valve. It combines a deluge dry-pipe valve with a pneumatic pilot system: pressure is held in the release circuit, and supervisory air pressure is held in the sprinkler pipework. Water enters the pipes only when a detection signal and a fall in air pressure from an open sprinkler both occur, which makes it a fit for data centres, archives, electrical rooms, museums, cold stores and other sites where an accidental discharge is costly.
Besides pneumatic release the valve can be operated electrically and manually in an emergency, and it can be installed vertically or horizontally with flanged or grooved connections.
Technical specifications
Values are from the Weflo Fig. 5311 data sheet.
| Parameter | Specification |
|---|---|
| Main valve | Same as Fig. 9266 deluge valve (ductile iron, diaphragm type) |
| Operation | Pneumatically actuated; also electric and manual emergency operation |
| Release | Double interlocked: needs both a detection signal and loss of air pressure in the sprinkler pipework |
| Rated pressure | 300 psi |
| Maximum air supply pressure | 30 psi |
| Connections | Flanged or grooved |
| Orientation | Vertical or horizontal installation |
| Approvals | UL listed in sizes 2, 2-1/2, 3, 4, 5, 6, 8, 10 and 12 in. |
Trim components
The data sheet lists 24 trim items. The main ones are shown here; optional items are marked in the sheet.
| Item | Function |
|---|---|
| Automatic water control valve, emergency manual release station, water relay | Core release hardware |
| Automatic drain valve, low-pressure drain valve, drain valve, check valve | Drainage and non-return |
| Y-strainer, trim valve, alarm test valve | Strainer and testing |
| Supply and system gauges, 0 to 300 psi | Indication |
| Water motor alarm, pressure supervisory switch (optional) | Alarm and supervision |
| Dry pilot and sprinkler piping pneumatic actuators, hydraulic actuator, air regulator, slow and fast fill valves, restrictor | Pneumatic release and air supply |
| Accelerator, pilot-line and sprinkler-pipe air supervisory switches, solenoid valve (optional) | Options |
Selection notes
Decide the release logic with the fire engineer: double interlock requires both detection and sprinkler operation before water flows, which differs from a single interlock. Check the available compressed air supply because the maximum air supply pressure is 30 psi, and confirm the optional supervisory switches and alarms required by the authority. The main valve is described in more detail under the Fig. 9266 deluge valve data.
Documents and quotation
The attached data sheet shows the trim schematic and the numbered parts list. For a quotation, send the size, connections, release arrangement, options and quantity. Further fire protection valves are under Fire Fighting.
Datasheets & Documents
- Datasheet Weflo Fig. 5311 Double Interlocked Pre-Action Valve data sheet Download
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About brand
Fire protection contractors meet the Weflo name on gate valves, hydrants and check valves for sprinkler and hydrant mains. Weflo Valve is based in Qingdao, China, and makes industrial and fire protection valves. Seven Star LLC lists the Weflo Fig. 1209 flanged balancing valve and supplies Weflo valves for building services and fire water projects in Oman on inquiry.
Weflo valve families
The manufacturer program covers OS&Y and NRS gate valves, fire hydrants, check and alarm check valves, butterfly valves, deluge, pre-action, pressure relief and pressure reducing valves, Y and basket strainers, and air relief valves. Weflo states that its OS&Y and NRS gate valves are UL listed and FM approved through 24 inches. Products are identified by figure number, as with the Fig. 1209 balancing valve in our listing.
Ordering Weflo valves: what we need
Send the figure number, size, end connection and flange standard, pressure rating, the medium, and the listing or approval the project specification demands. Approvals apply per figure and size, so we check each line against the manufacturer datasheet. GCC civil defense requirements should be quoted in the request.
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Frequently Asked Questions
What does double interlocked mean?
Water is admitted to the sprinkler pipework only when both the detection system operates and sprinkler piping air pressure is lost.
What is the rated pressure of the Fig. 5311?
The rated pressure is 300 psi, with a maximum air supply pressure of 30 psi.
Which sizes are UL listed?
The data sheet lists UL approval in 2, 2-1/2, 3, 4, 5, 6, 8, 10 and 12 in.
Can it be operated manually?
Yes. It can be operated electrically and manually in an emergency through the emergency manual release station.
Is the main valve the same as the Fig. 9266?
Yes. The data sheet states that the main valve is the same as Fig. 9266.
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