What is the minimum required residual pressure established by fire protection engineers when calculating available water for area flow?

The minimum required residual pressure established by fire protection engineers when calculating available water for area flow is essential for ensuring adequate fire protection. A residual pressure of 20 psi is considered the standard minimum because it ensures that there is sufficient pressure available in fire hydrants and standpipe systems to deliver an effective flow of water during firefighting operations. This pressure level is critical for maintaining a proper water supply, especially in urban areas where fire risk is higher and where building heights may increase the necessary elevation to reach fire suppression sprinkler systems.

Setting the minimum at 20 psi allows for the required flow rates necessary for effective fire control without compromising the safety and effectiveness of firefighting efforts. It accommodates pressure losses that can occur due to friction in the plumbing systems and ensures that enough pressure is available even when multiple hydrants or sprinklers are in use simultaneously. This standard helps in creating a reliable and efficient response plan for firefighters in real emergencies.