It depends. There are three common ways that liquid water can enter through a breather valve: submersion in water, directed streams of water (washdowns), and wind-driven rain.
For submersion, the valve will not open if the reseal pressure of the valve exceeds the .hydrostatic pressure of the water plus any vacuum that has built up inside the container. Submerging a warm container in cold water will develop a vacuum inside the container. If your container is subject to this condition, contact us for assistance in calculating its effect on your container.
For washdown, the breather valve’s cover configuration and vacuum setting determine whether it is susceptible to water ingress. Our AGM breather valves with a solid cover and a nominal cracking pressure in the vacuum direction of at least 1.0 psid will repel water entry from a directed stream of water. AGM valves with a solid cover include the following: TA333-R, TA330, TA770-R, and TA225.
Finally, for the condition of wind-driven rain, our AGM breather valves with a solid cover will repel wind-driven rain even when the valve is inhaling. AGM’s unique cover design forces the airstream through two 180° turns, thereby causing most water droplets to fall out of the air stream.
Note that the passage of liquid water through a valve is only one way moisture can enter a container. The more common way for moisture to enter a container is in the form of water vapor. Contact us for assistance in determining how to protect your container’s contents against this type of water ingress.