What should atmospheric type vacuum breakers not be subjected to?

Atmospheric type vacuum breakers are specifically designed to prevent back siphonage by creating a physical barrier against contaminants. They operate effectively under atmospheric pressure and are meant to break the vacuum condition that can occur in a plumbing system.

When subjected to back pressure, atmospheric vacuum breakers may fail to function correctly as they rely on atmospheric pressure to operate. This condition can compromise their ability to prevent the backflow of contaminated water into potable water supplies, which could pose a serious health risk. Therefore, ensuring that they are not subject to back pressure is crucial for maintaining the integrity and safety of the plumbing system. This is why the focus is on the importance of avoiding back pressure in the use of atmospheric type vacuum breakers.