California Alarm Company Operator Licensing Practice Exam 2026 – The All-in-One Guide to Exam Success!

Sprinkler heads with a fusible link use a metal that melts at a specific, low temperature to release the valve when heat is reached. Wood's metal, also called Lipowitz alloy, is a fusible alloy chosen for this role because its melting point is relatively low (about 70°C / 158°F). When the surrounding temperature hits that point, the alloy melts and the sprinkler head activates, allowing water to flow. Tin solder melts at a much higher temperature, Bronze and Aluminum have even higher melting points, so they wouldn’t serve as reliable low-temperature fusible links for sprinkler heads. That’s why Wood's metal is the correct material.