Air Valves are essential components complete pipeline design. The designed pipeline flow capacity will not be achieved without essential air valves because of air pocket buildups which can cause flow capacities to be reduced by 5% to 15% of designed flow.... unfortunately reduced capacities may go unnoticed because air is an invisible culprit in pipelines. Air pockets increase energy consumption because pumping operation will be at higher heads to overcome air constricted flow.



Air valves are not expensive and more than pay their way by greatly improving pipeline efficiency. Air Valves represent low cost insurance to protect expensive Pipelines and Pump Stations. It is a well known fact; air pockets are a major cause of pressure surges and water hammer in pipelines.

There are many different kinds of backflow valves. Check out for which kind of valves you can use in your area. Atmospheric vacuum breaker, a cheaper valve installed on the pipe right after the control valve. It needs to be installed higher than the highest sprinkler head operated by that valve-check with local officials to find out if there's a code. You probably need to use this kind if you have six or more valves.

Pressure vacuum breakers are similar to the ones above except that you only need to install one of them along the mainline leading to the control valves.

Anti-siphon valves, the most common type, have a built-in atmospheric vacuum breaker and also must be installed higher than the highest sprinkler head.

Reduced pressure backflow preventers are more expensive, used mostly in commercial irrigation installations. If you want a top-quality valve, this is the one. Double check backflow preventers; they're legal in many places, illegal in others.