What type of system usually requires an Atmospheric Relief Valve?

An Atmospheric Relief Valve is primarily utilized in systems that experience variations in pressure, particularly to ensure that negative pressure does not cause issues such as siphoning or collapse of system components. In this context, single equipment systems often require an Atmospheric Relief Valve to prevent vacuum conditions that can occur if the equipment operates in a closed loop while drawing fluids or gases.

For example, in a single piece of heating equipment or a hot water storage tank, as water is drawn off or heated, the potential for a negative pressure situation can arise. The Atmospheric Relief Valve allows air to enter the system, thereby preventing a vacuum and allowing for proper fluid flow without damaging the equipment.

Other system types, such as multiple equipment systems or complex plumbing systems, may utilize different types of valves and pressure management strategies due to their inherent complexity and interconnections. However, a single equipment system remains a straightforward application where an Atmospheric Relief Valve serves a critical role in maintaining operational integrity and safety.