How should vacuum relief valves be installed according to standard practices?

Vacuum relief valves are essential in plumbing systems, particularly in preventing vacuum conditions that can lead to siphoning or collapse of pipes and systems. Installing vacuum relief valves in multiples is a standard practice because it allows for redundancy and enhanced reliability in the plumbing system. When multiple valves are installed, they can provide better protection against potential vacuum scenarios that might occur due to variations in system operation or larger drafts on the plumbing layout.

Having several valves ensures that if one valve fails or gets blocked, others can still function, significantly reducing the risk of system failure. Additionally, in larger systems or those with significant elevation changes, a single vacuum relief valve may not be sufficient to manage the varying pressure conditions throughout the system. Therefore, by installing vacuum relief valves in multiples, plumbers can ensure the integrity and safety of the entire plumbing system under different operating conditions.

While a vacuum relief valve should also be installed at the highest point of the system to effectively release any built-up vacuum, relying solely on a single valve may compromise the system during peak operations. Thus, multiple installations help cater to the dynamic nature of plumbing systems and ensure they operate smoothly without creating dangerous vacuum conditions.