What does head pressure refer to in fire service operations?

Head pressure refers to the pressure created by the vertical height of water above a specific point, which plays a critical role in fire service operations. This concept is essential when considering how altitude affects water delivery in firefighting scenarios.

When water is elevated, such as in a storage tank or in the hoses leading to a higher elevation, the weight of that water exerts pressure downward. This is measured in terms of feet of water, where every 1 foot of elevation corresponds to approximately 0.433 psi (pounds per square inch) of pressure. As firefighters position their hoses and equipment at various elevations, understanding head pressure allows them to ensure they have sufficient water pressure to effectively combat fires.

Understanding this principle is vital for pump operators who must account for elevation changes when calculating the necessary pump discharge pressure to deliver water effectively to the fire scene.