Where are post indicator valves required?
A listed indicating valve at each connection into the building that is located at least 40′ from the building (if space permits) Control valves in a cutoff stair tower or valve room accessible from the outside. Valves located in risers with indicating posts arranged for outside operation.
Is a PIV required?
The PIV’s Pivotal Role The NFPA technically does not require a PIV as long as the control valve of the fire sprinkler’s water supply is both listed and has an indicator on it.
What is the post indicator valve?
Installed in the main water line serving a building, the Post Indicator Valve (PIV) is a valve used to control the water supply to the fire sprinkler system. The PIV has a display that shows whether water is being pumped into the system (“OPEN”) or not (“CLOSED”).
What is the purpose of a post indicator valve?
Purpose of Post-Indicator Valves Post-indicator valves have long been used to stop the flow of water into a building during developed stages of a fire. Exterior wall collapse of a burning building poses a threat to break water supply mains as well as create many openings to the water supply.
How do you perform a valve inspection?
Valve Shell Test The valve shall be partially open and be able to hold pressure for a certain time. The pressure shall not be less than 1.5 times of maximum working pressure. No leakage is allowed. Leakage check points are body, bonnet, stem, plugs/fittings and flange connections.
Should sprinkler valves be open or closed?
Make sure the sprinkler valve is closed, unless it’s the valve farthest from the main water source. You’ll want to leave this valve open and remove the sprinkler nozzle to allow air to escape when you turn on the water.
What type of valve is a butterfly valve?
The butterfly valve is classified as a quarter-turn valve. It works like a ball valve for quick shutoff, but unlike a ball valve, the butterfly valve can also open and close incrementally. This difference means that the disc is always present in the flow and allows for a drop in pressure.
Which valve is better for on off control?
When you need precise control over your application, a globe valve will be more accurate than a ball valve. Globe valves are considered the industry standard for control valves because they are good at regulating flow, whereas ball valves are better for on/off control without pressure drop.
What is difference between ball valve and butterfly valve?
Generally speaking, a ball valve is a ball with a hole through it. A butterfly valve generally consists of a disk mounted on a rotating shaft. When using a ball valve, turning the valve handle moves the hole in the ball to either block, partially block or open the flow of gas or liquid through the valve.
What is difference between gate valve and butterfly valve?
The gate valve is a kind of cut-off valve, which can only be fully open or fully closed, and the flow cannot be adjusted. Butterfly valve, also known as flap valve. Its opening and closing member is a disc-shaped disc which is fixed on the valve stem and rotates around the stem valve shaft to open and close.
Which is better butterfly or ball valve?
At larger diameters, butterfly valves are generally regarded as cheaper than ball valves. They have the least amount of parts and are relatively lightweight, requiring less support. The weight advantage of butterfly valves to ball valves can be significant at larger pipe diameters.
Which is better butterfly valve or gate valve?
Advantages and Disadvantages of Butterfly and Gate Valves. Pressure differential: gate valves are generally better than butterfly valves at performing under pressure. Their construction means that flow can keep going without creating any undue pressure fluctuations. And their use doesn’t take much effort.
What is butterfly valve not suitable for?
Butterfly valves do have limitations that make them unsuitable for flow control in some applications. These include a limited pressure drop capability compared to globe ball valves with greater potential for cavitation or flashing.
What controls the butterfly valve?
A butterfly valve controls flow through a pipe using a single disc mounted on a central shaft. A resilient seated butterfly valve includes a rubber seat between the outer diameter of the disc and the inner wall of the valve.
Can a butterfly valve regulate flow?
Unlike gate valves, butterfly valves can be used for throttling or regulating flow as well as in the full open and fully closed position. The pressure loss through a butterfly valve is small in comparison with the gate valve. The L/D ratio for this type of valve is approximately one-third of that of a gate valve.