How is a sprinkler system typically activated?

• A. Heat from a fire.
• B. Smoke detector sensors trigger activation.
• C. A manual pull station is required to activate automatically.
• D. Water pressure loss activates sprinkler systems.

Answer: (A)

Sprinkler systems release water in direct response to heat at the sprinkler head. Each head contains a heat-sensitive element (like a glass bulb or fusible link) that must reach its rated temperature to open and allow water to flow. When heat from a fire reaches that head, water discharges from it, and in most systems only the activated head (or heads in that zone) releases water. Smoke detectors are used for detection and alarms, not automatic sprinkler activation. Manual pull stations exist in some setups for manual activation, but they aren’t the automatic trigger in a standard system. A drop in water pressure isn’t what starts the discharge; it may indicate a problem or that water has been released, but it isn’t the activating mechanism.