What is the purpose of entrained air in a pressured line?

Entrained air refers to small bubbles of air that are mixed into a fluid, and its presence in a pressured water line can have several functional implications. When considering the purpose of entrained air in a pressured line, it primarily serves to minimize the risk of negative pressure conditions and potential system collapses by providing a means for the air to escape if needed. In scenarios involving changes in water flow or in the event of a pressure drop, entrained air allows the water system to manage these fluctuations more effectively, thereby reducing the risk of damage to the infrastructure.

On the other hand, while some might think that entrained air could improve water pressure or allow for continuous flow, these functions are not directly related to the concept of entrained air in pressured lines. In fact, too much air can cause issues like cavitation or noise in the system, highlighting that the management of air within the system is critical. As for preventing freezing, while entrained air can contribute slightly to insulation against freezing temperatures, its primary necessity revolves around facilitating pressure management and system integrity.