When supplying automatic sprinkler systems, pressure should be built up slowly to how many psi at the fire department connection?

When supplying automatic sprinkler systems, it is important to build up the pressure slowly to ensure the system is not subject to hydraulic shock, which can damage the pipes or fittings. The correct pressure at the fire department connection should be set to 150 psi. This pressure is typically high enough to adequately supply the sprinkler system while also allowing for a safe increase that will prevent any sudden surges in water flow.

Choosing 150 psi optimizes performance for most sprinkler systems, allowing them to operate effectively while maintaining the structural integrity of the system. Pressures that are too low may not adequately activate all the sprinkler heads, while too high pressures can lead to potential failure points in the system, making 150 psi a balanced and generally accepted standard in fire service practices.