What factors should be considered when estimating demand pressure for fire operations?

When estimating demand pressure for fire operations, elevation and hose length are critical factors to consider. As fire operations typically involve pumping water through hoses to deliver it to an emergency scene, both of these elements directly affect the pressure required to ensure that water reaches the desired location effectively.

Elevation plays a significant role because as the height increases, the pressure must also increase to overcome the gravitational pull. For every story a fire is above ground level, the pressure needed to deliver water effectively rises, often calculated at approximately 5 psi per floor. This increase in pressure is necessary to ensure that the hose can maintain adequate flow rates and reach the intended destination.

Hose length is another important factor because the longer the hose, the more friction loss occurs as water travels through it. Each length of hose has a specific friction loss based on its diameter and the flow rate being used. Additional hose length results in reduced water pressure at the nozzle, which can seriously impact firefighting effectiveness. Therefore, both elevation and hose length have to be carefully calculated and adjusted for when estimating demand pressure during fire operations to ensure proper water delivery under firefighting conditions.