Air Release Valve

Name: Air Release Valve
Brand: Ayso Fire Protection

An air release valve is a float-type valve that automatically discharges air accumulating at high points of the pipeline or in the pump casing while the system operates under pressure. Mounting point, working pressure and drain connection are considered when selecting an automatic air release valve.

Cla-Val 34 Series Automatic Air Release Valve

According to Cla-Val, air accumulating in lines without an air release valve reduces flow capacity over time, increases energy consumption and can eventually cause air locking. Large air pockets also amplify the pressure surges that occur when the system starts and stops.

The Cla-Val 34 Series operates normally open. When accumulated air displaces the water in the body, the float drops and opens the discharge orifice. After the air is released the valve fills with water, the float rises and the orifice closes. This cycle repeats automatically as air accumulates.

The valve is offered with an epoxy-coated ductile iron body, a 316 stainless steel float and a 400 psi pressure class, and can be serviced without removal from the line. Cla-Val's model 3410-AR116.400 is listed in UL Product iQ under 'Air-release Valves for Fire Pumps'. Air release valves can also be supplied under the Weflo brand.

Air Release Valve Technical Specifications

Specification	Value
Listed Size	1″ (with 1/2″ and 3/4″ reducing bushings)
Inlet / Outlet	1″ NPT / 1/2″ NPT (1/16″ orifice)
Pressure Class	400 psi
Temperature	Water service, up to 180 °F
Body and Cover	Epoxy-coated ductile iron, ASTM A536 65-45-12
Float / Internals	316 stainless steel / stainless steel and Delrin
Elastomer	Buna-N
UL Listing	Air-release Valves for Fire Pumps – EX26932 (Model 3410-AR116.400)

Technical values are based on manufacturer documents; confirm against the current data sheet before ordering.

Air Release Valve Applications

Releasing air accumulated in the fire pump casing

High points of fire protection piping

Sprinkler systems (installed in accordance with NFPA 13 / 13D / 13R)

Seawater and heavy-duty applications (with optional materials)

Related Fire Pump Accessories

Other equipment considered together with the Air Release Valve in the fire pump room:

Frequently Asked Questions

Why is an air release valve needed?

Air accumulating in the line reduces flow capacity, increases energy consumption and amplifies pressure surges. The air release valve discharges this air automatically while the system is running.

Where is the valve installed?

It is installed vertically at the highest point of the pipeline or pump casing. An isolation valve is fitted below it for ease of service.

Where should the discharge line be routed?

According to the manufacturer, the valve may discharge some liquid as it closes. The discharge line should therefore be routed to an open drain.

Is the 34 Series UL listed?

The manufacturer's model 3410-AR116.400 is listed in UL Product iQ under 'Air-release Valves for Fire Pumps' (EX26932).

Does the valve need to be removed from the line for maintenance?

No. The 34 Series is designed to be serviced without removal from the line.

Can it be used in seawater applications?

Yes. Optional materials such as NAB, Monel, 316 stainless and super duplex are offered for seawater and heavy-duty service.