Most of the time, a properly-sized standard air valve does exactly what you need it to: it releases trapped air or lets air in to prevent vacuum – protecting your line and keeping your system running smoothly.
But every now and then, we come across an application that pushes the limits. Surge prone systems with high pressures or particularly corrosive environments can chew through air valves that otherwise should hold up just fine. When that happens, it’s time to look at something built for more extreme conditions – like Cla-Val’s 39 Series Air Valve.
Why Do We Need Air Valves?
Every water system, no matter how well designed, needs to account for the air that’s already present in water, which is roughly 2% air by volume. Air also sneaks in through pumps, joints, and fittings, collects at high points, and causes all kinds of headaches if not managed.
Air valves are installed to:
let air escape so the pipeline can charge properly (during filling)
release small amounts of entrained air that would otherwise rob your system of efficiency (during operation)
draw air back in so the line doesn’t collapse under vacuum (during draining)
When air is not properly managed, it can cause surges, reduce efficiency, stop flow entirely, and in extreme cases, it can collapse your pipeline.
When Standard Air Valves Fall Short
In most systems, standard AWWA-compliant air valves are the right choice. But while they are proven, cost-effective, and reliable, there are certain scenarios where they just can’t keep up:
High pressures that exceed standard valve ratings
Frequent surge or slam events from pump trips or rapid valve closures
Lines that are regularly (or quickly) filled and drained – such as irrigation systems
Corrosive or harsh environments where stainless steel is a must
Applications where other air valves have failed – sometimes repeatedly
When we talk with operators and engineers facing these kinds of challenges, the pattern is familiar: they’ve tried the typical air valves, but the problems keep coming back. That’s when it makes sense to look at something built for more extreme conditions.
The Cla-Val 39 Series: Built for Extreme Conditions
Cla-Val’s 39 Series Air Valve isn’t your everyday combination air valve. Most combination air valves handle air release and vacuum. The 39 Series goes further, adding surge protection and high-pressure capability in a single package.
The valve performs four functions in one:
High-volume air discharge during filling: allowing air to escape at the same rate water enters the line
Anti-slam air discharge during surge events: protecting pipelines from damage when conditions change rapidly
Pressurized air release through a small orifice: preventing air pockets and maintaining efficiency once the line is charged
Vacuum break during draining: allowing air back in as fast as the water exits
Stainless steel materials, precision-machined components, and a true anti-slam float mechanism all work together to handle high pressures and dynamic conditions that push standard air valves beyond their comfort zone.
The 39 Series in an investment, and not every system needs it. But for high-pressure, high-surge conditions where standard valves fail, it’s the option that pays off in durability and long-term reliability.
Is the 39 Series Right For You?
If your system runs high pressures, sees frequent surges, or has already burned through other air valves, it might be time to consider the 39 Series.
Our team works with operators and engineers across the Pacific Northwest to match the right valve to the right applications. Often that’s a standard air valve, but sometimes a specialty solution like the 39 Series is exactly what’s needed.
Reach out to our team to talk through your system. We’ll help you determine what makes the most sense for your application.