Firefighter 2 Practice Exam 2026 – Complete Preparation Guide

Deluge systems keep the distribution piping dry until activation, and every sprinkler head is open. When the system is activated, water is released into the entire piping network and flows from all heads at once. This setup provides immediate, total coverage because there are no closed heads waiting to vent water individually.

This differs from wet-pipe systems, where the pipes themselves are full of water from the start, so a single heated head releases water instantly but not all heads are open. In dry-pipe systems, the pipes are filled with pressurized air or nitrogen and water only enters after the dry-pipe valve is triggered, with heads remaining closed until that happens. In preaction systems, water is kept out of the piping until a detection device triggers water into the pipes, and then the heads release water only after a sprinkler is activated.