Which is a release mechanism in a sprinkler head?

• A. Deluge
• B. Large volume
• C. Fusible link
• D. Pyrophoric action

Answer: (C)

The release mechanism in a sprinkler head is the heat-activated element that holds the head closed until heat from a fire triggers it. A fusible link is a temperature-sensitive metal alloy that melts at a designated temperature. When heat reaches that point, the link melts and releases the sprinkler’s sealing plug, allowing water to flow through the head. This directly describes how the head is opened in response to fire. The other terms describe system types or actions rather than the mechanism inside the head: deluge refers to a system where all sprinklers discharge, large volume isn’t a release mechanism, and pyrophoric action isn’t used as a standard sprinkler head release method.