Air Release Valve

There are two types of air release valve commonly used 

  • Single Chamber air release valve
  • Double Orifice / Chamber air release valve

Single Chamber air release valve:-

Air release valves, also called single function air valves, are designed only to release air pockets accumulated during working conditions. Something important we must take into account about this model is that they don’t have any capacity of air inflow during pipe draining, and outflow during filling, due to the limited passage through the nozzle, therefore they won’t provide any protection for the pipeline against negative pressure conditions.

Single Chamber air release valve kinetic type Air Valve with Tamper proof design offers solution for releasing and adding air to water pipelines, protecting pipe line systems and improving efficiency. Our air valves are made in ductile cast iron body with floats in stainless steel.

Air/Vacuum release valves 

Vacuum air valves,  also called double function air valves, are designed to protect the pipeline during pipe draining and filling operations.

In case of pipe draining we must allow the entrance of large volumes of air, when the pressure drops below atmospheric values, to avoid negative pressure conditions and damages to the system.

In case of pipe filling we must discharge large volumes of air to avoid the creation of air trapped in dead ends, with possible upsurges, and to speed up the filling process saving time and money

Advantage of Air Release Valve :

  • A single chamber full bore combination air valve, to avoid the problems typical of the double float design allowing at the same time for reduced space and weight with a PN 40 bar product; – high flow capacity thanks to shapes and passages into the body studied with advanced computational fluid dynamics calculations.
  • Cylindrical floats and obturator in solid polypropylene to avoid deformation, calcium deposits and jamming, typical problems of spherical floats.
  • Air release subset in stainless steel AISI 316 with gasket compression control to minimize the risk of leakage.
  • Air release valves protect the pipeline system and maintain its efficiency. These valves are perfect for quickly venting large volumes of air during filling or startup. They also allow air back into the pipeline during emptying. This is important because some pipe materials can collapse under negative pressure. Once an air release valve is installed, it constantly operates automatically.


If a pipeline is filled or emptied too quickly, an air release valve does not always keep up with the air flow demands. You must size the valve correctly for your application.

Now you know that an air release valve is important for many piping system applications. Do you have a pipeline that might need an air release valve? Make sure you get the right valve for the job by talking to an experienced engineer.

Installation of air release valve :

Before installation make sure to accurately clean the pipeline to avoid that any foreign bodies like stones or building material may damage the air release valves. Air release valves must be positioned in locations wide enough and easily accessible to allow maintenance, operations nd inspection. They must be placed in a perfectly vertical position, and on a “T” piece to allow for air accumulation in order to improve the air valves performances. The pit must be equipped with a drainage system for cleaning operations, and ventilation pipes to allow air intake and outflow for the proper air recirculation. A sectioning device, being either a gate valve or a butterfly valve, must be provided.

Air valves location installation

  • An example of how to deal with high points. A three function air valve has to be placed on top of an accumulation chamber, it is important to install the air valve on the  ownstream side of the high point due to the position of the air pocket which, pushed by the hydrodynamic force of water from one side and the buoyancy and friction force from the other, will be likely to remain near the change in slope. These locations are often exposed to water hammer effects therefore antislam air valves are recommended.
  • On descending changes in slope we always design on conservative assumptions, therefore air pockets are expected to accumulate on the change in slope due to low velocity conditions. Three functions air valves will be necessary.
  • On ascending changes in slope air vacuum air valves will be needed since the air pockets will be always flushed upstream, these points are often exposed to water hammer conditions therefore air valves with anti-slam technology are highly recommended

Air release  valves installation effect on pipe Line 

Application of air release valve

Water pipelines and sewer force mains are popular areas to find air release valves. If correctly installed, you should see them at the peaks and high points of the system. Sometimes they might be slightly downstream or paired with a combination air valve. Air release valves are ideal for any type of closed loop or pressurized piping that can entrap air.

Double Orifice / Chamber air release valve :

Double Orifice / Chamber air release valve combine both large and small orifices within one valve and offers solution for releasing and adding air to water pipelines, protecting pipe line systems and improving efficiency. The three function automatic air valve discharge the large volume of air during charging of the pipeline, admit air during emptying of the pipeline and discharge air accumulated under normal operating conditions. Air valve offered with a kinetically designed large orifice and float to avoid premature closing of the valve by the discharging air. The small orifice is sealed by a float at all pressure above atmospheric except when air accumulates in the valve body. Air valves are made in ductile iron body with floats in stainless Steel. Valves are suitable for clean and neutral water to a maximum temperature of 70° C.

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