Guide to Butterfly Valve for Fire Protection

What Is a Butterfly Valve

A butterfly valve is a quarter-turn valve that uses a rotating disc to regulate flow. When the disc is parallel to the pipe, the valve is open. A 90° turn closes the valve by placing the disc perpendicular to the flow.

Butterfly valves can be manual (operated by a lever or gear) or automatic (operated by electric or pneumatic actuators). In fire protection, they are often used for isolation and control in sprinkler systems, standpipes, and fire pump installations.

Why Use Butterfly Valves in Fire Protection

• Space-saving design – Their compact body requires less space, making them ideal for tight installations.

• Quick operation – The quarter-turn mechanism ensures fast opening or closing in emergencies.

• Lower cost – They are generally more economical than gate valves of similar size.

• Visual position indication – Many fire protection butterfly valves come with tamper switches and position indicators that integrate with fire alarm systems.

• Reliable sealing – Designed with elastomer seats, they provide bubble-tight shutoff.

Types of Butterfly Valves in Fire Protection

1. Wafer-style butterfly valves – Lightweight and cost-effective, installed between two flanges. Best for smaller systems with limited space.

2. Lug-style butterfly valves – Feature threaded inserts for secure bolting, suitable for dead-end service and higher reliability.

3. Grooved-end butterfly valves – Common in fire protection piping because of easy installation with grooved couplings.

4. OS&Y (Outside Screw & Yoke) indicators – Provide visual confirmation of open/closed position, critical for fire system inspection.

5. Supervisory switch-equipped butterfly valves – Connected to alarm panels to monitor valve status and alert if the valve is closed.

Where Are They Used in Fire Protection Systems

• Sprinkler system risers – As control valves to isolate sections of the system.

• Standpipe systems – To regulate water supply across multiple floors.

• Fire pump discharge lines – For controlling water flow from pumps to distribution systems.

• Zone isolation – Allowing maintenance on one section of the system without shutting down the entire building.

Installation and Maintenance Considerations

• Correct orientation – Install valves with disc rotation clear of obstructions.

• Accessibility – Place valves in easily reachable locations for inspection and operation.

• Supervisory integration – Always connect tamper switches to the fire alarm system.

• Regular testing – Follow NFPA 25 guidelines, which require periodic operation and inspection of control valves.

• Corrosion prevention – Use coatings or select valve materials suitable for the environment.

Advantages Over Gate Valves

• Lighter weight → easier installation.

• Quarter-turn operation → quicker response.

• Built-in supervisory features → simpler compliance with NFPA standards.

• Lower cost for larger diameters → cost efficiency in big systems.

  
  

Choosing the Right Butterfly Valve

• Confirm it meets UL/FM approvals for fire service.

• Choose the correct end connection (grooved, wafer, lug) for your piping system.

• Verify it has a supervisory switch for alarm integration.

• Match the size and pressure rating to your system requirements.

• Consider environmental conditions (corrosive water, outdoor exposure) when selecting body and disc materials.