What usually activates a sprinkler head that results in a discharge of water?

• A. Smoke
• B. Low Pressure
• C. Heat
• D. Fire Detection Devices

Answer: (C)

Sprinkler heads are designed to discharge water when their heat-sensitive element is activated. Each head contains a mechanism—such as a glass bulb with a liquid or a fusible link—that is rated to break or melt at a specific temperature. When the surrounding heat reaches that rating, the element fails and the head releases, allowing water to spray out to control the fire. Smoke doesn’t directly trigger the sprinkler head, and low pressure won’t cause discharge by itself. Fire detection devices may start the overall fire response or open downstream valves, but the actual water release from a standard sprinkler head is caused by heat at the head itself.