Which sprinkler head is activated by a fixed temperature, causing discharge without manual operation?

Which sprinkler head is activated by a fixed temperature, causing discharge without manual operation?

• A. Frangible Head
• B. Link Head
• C. Glass Bulb Head
• D. Electronic Head

Answer: (C)

Activation by a fixed temperature means the sprinkler will release water automatically once the surrounding temperature reaches a set rating, with no manual action needed. The glass bulb head does this through a small glass bulb filled with a heat-sensitive liquid. When heat reaches the bulb’s rated temperature, the liquid expands until the bulb ruptures. That break frees the plug and opens the sprinkler, allowing water to discharge immediately. Other temperature-activated options use different mechanisms—some rely on a frangible element that breaks, some on a fusible link that melts, and others on electronic sensors. These are all automatic, but the glass bulb head is the classic example of a fixed-temperature activation, which is why it’s the best answer here.

Activation by a fixed temperature means the sprinkler will release water automatically once the surrounding temperature reaches a set rating, with no manual action needed. The glass bulb head does this through a small glass bulb filled with a heat-sensitive liquid. When heat reaches the bulb’s rated temperature, the liquid expands until the bulb ruptures. That break frees the plug and opens the sprinkler, allowing water to discharge immediately.

Other temperature-activated options use different mechanisms—some rely on a frangible element that breaks, some on a fusible link that melts, and others on electronic sensors. These are all automatic, but the glass bulb head is the classic example of a fixed-temperature activation, which is why it’s the best answer here.