What type of pressure is typically lower than fire suppression pressure in a water system?

Residual pressure refers to the pressure that remains in a water system after water is drawn from it, such as during firefighting operations. This pressure is typically lower than the static pressure, which is the pressure in the system when water is not flowing. Fire suppression systems require a certain pressure to effectively deliver water to fight fires, and this pressure is often higher than the residual pressure encountered once a significant volume of water is extracted from the supply.

When firefighters pull water from a hydrant or a system, the act of drawing water decreases the overall pressure available at that source, resulting in the residual pressure. This pressure is significant because it indicates how much lower the available flow pressure is compared to the potentially higher static pressure, ultimately impacting the available flow rate and effectiveness during firefighting efforts. Understanding residual pressure—and how it influences firefighting operations—is essential for effective water supply management in emergencies.