Firefighting systems typically utilize several types of valves to control the flow of water or other extinguishing agents. These valves are crucial for maintaining proper pressure, directing water flow, and shutting off the supply in emergency situations. These valves are critical components that help firefighters manage water distribution, pressure, and direction.Here are some common types of valves used in fire fighting systems:
Gate valves are commonly used in fire protection systems for their full-flow characteristics and reliable shut-off capabilities. They have a flat closure element (gate) that slides up and down to control the flow of water. When the gate is fully open, it allows maximum water flow, and when fully closed, it stops the flow completely. These valves are typically used to isolate sections of the system and are often found at the inlets and outlets of fire hydrants, fire pumps, standpipe, and water mains. Gate valves may have either rising or non-rising stems, where the stem moves up and down or stays in place during operation, respectively.
OS&Y (Outside Screw and Yoke) Valve
OS&Y valves are a type of gate valve that provides visible indication of whether the valve is open or closed. When the valve is open, the valve stem protrudes from the yoke, and when it’s closed, the stem is not visible. This feature is useful for firefighters to quickly identify the status of the valve during emergency operations.
Ball valves are another prevalent type of valve in fire protection systems. They have a spherical ball with a hole in the center, which controls water flow by rotating the ball within the valve body. When the ball’s bore aligns with the pipeline, the valve is fully open, allowing water to flow freely. Conversely, a 90-degree turn of the handle closes the valve completely. Ball valves are widely used in hydrants, standpipes, and hose connections.
Ball valves are commonly used in fire protection systems due to their quick and reliable on/off operation.
Butterfly valves are versatile and lightweight, making them suitable for use in fire protection systems. These valves have a disk that rotates on a shaft to control water flow. When the disk is parallel to the flow direction, it allows water to pass through, and when it’s perpendicular, it closes the valve. These valves are often used in large-diameter piping, such as in fire pump discharge lines and water storage tanks where quick operation and low pressure drop are essential.
Pressure Reducing Valve (PRV)
Pressure-reducing valves are essential for maintaining optimal water pressure in the fire protection system. They automatically reduce the incoming water pressure to a Pre-set level, ensuring the system operates within safe and efficient parameters. PRVs are frequently installed in fire sprinkler systems to prevent damage to the system and control the water flow to individual sprinkler heads. This is crucial to protect the system components and prevent unnecessary water wastage due to excessive pressure.
Pressure Relief Valves
Pressure relief valves are safety devices that open automatically when the pressure exceeds a predetermined limit. In fire protection systems, they prevent over-pressurization, which can lead to system damage or failure. Pressure-relief valves are commonly found in fire pump discharge lines and in systems where pressure fluctuations are a concern.
Check valves, also known as non-return valves, are designed to flow in one direction only. They are installed to prevent back-flow in fire protection systems, ensuring water doesn’t flow back into the supply line. Check valves are commonly used in fire pump discharge lines and sprinkler systems.
Alarm Check Valve
An alarm check valve combines a check valve with a water flow alarm system. It triggers an alarm when there’s water flow in the system, indicating the activation of sprinklers or other firefighting devices.
Deluge valves are used in deluge systems, which are designed to protect high-hazard areas or objects that require a large amount of water quickly. Deluge valves stay open at all times, and the system relies on activation of fire detection devices (smoke or heat detectors) to release water into the protected area. These valves are commonly used in industrial facilities and areas with a high risk of fast-spreading fires.
Preaction valves are used in preaction fire protection systems, which combine features of both dry pipe and deluge systems. Preaction systems use automatic detection devices, but they require a supplemental activation signal before water is released into the piping. Preaction valves allow for quicker response times and reduce the risk of accidental water release in areas sensitive to water damage, such as data centers and museums.
Pressure-regulating valves are used to maintain constant water pressure in specific sections of the fire protection system. These valves are particularly helpful in buildings with varying water supply pressures or where the elevation changes significantly. Pressure-regulating valves ensure that water reaches all sprinkler heads with consistent pressure, enhancing the effectiveness of the system.
Angle valves are used for making changes in direction within the fire protection piping network.
Water Motor Gong (WMG) Valve
Water motor gong valves are used to provide an audible alarm in fire protection systems. They use the water flow to drive a turbine, producing a loud noise that alerts occupants about a fire event.
The selection of valves in a fire fighting system depends on various factors such as the type of extinguishing agent used, building size, occupancy type, fire risk, and local building codes. It’s essential to consult with fire protection engineers and comply with local fire codes and regulations when designing and installing fire fighting systems.
Regular maintenance and testing of these valves are critical to ensure their proper functioning during emergencies and to comply with relevant safety standards.