Which sprinkler head mechanism is a standard fusible link?

• A. Fusible link - quick response
• B. Fusible Link - Standard
• C. Chemical Pallet
• D. Frangible Bulb

Answer: (B)

Sprinkler heads rely on a heat-activated element to release water. The standard fusible link is a metal alloy that melts at a defined temperature, releasing the plug and allowing water to flow through the head. This is the traditional, non-rapid-response mechanism used in many systems. Quick-response heads use a more sensitive element to react faster; frangible bulbs rely on a glass bulb that breaks when heated; chemical pallets use a pellet that expands with heat to drive the mechanism. Because the question asks for the standard fusible link, the mechanism described is the classic fusible link that melts at its rated temperature, not the faster-responding or alternative types.