Air Release Valve
An air release valve is a special type of valve used in water supply, wastewater, and pipeline systems to automatically release trapped air from the pipeline during filling and normal operation, and sometimes to admit air during draining.
Why is an Air Release Valve Needed?
Air can enter pipelines during:
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Initial filling of the pipeline
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Pump start/stop operations
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Leakage or maintenance work
Trapped air can cause:
Reduced flow capacity
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Increased head loss
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Pipe corrosion
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Water hammer and pipe bursts
Functions of an Air Release Valve
- Releases accumulated air at high points in the pipeline.
Prevents air locking, which restricts water flow.
Reduces surge and water hammer effects.
Maintains smooth and continuous flow.
Types of Air Valves
Air Release Valve (Small Orifice):
Releases small pockets of air during normal operation.-
Air/Vacuum Valve (Large Orifice):
Releases large volumes of air during filling and admits air during draining. -
Combination Air Valve:
Combines both small and large orifice functions in one unit.
Where are Air Release Valves Installed?
At high points of pipelines
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Near pumps and pumping mains
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At changes in slope
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At long pipeline sections
