What is Fusible Loop?

What is a fusible loop charge panel? A fusible loop charge panel is a pneumatic panel that monitors a fusible loop system for the detection of fire. Fusible loop system are installed on offshore platforms to detect fire. The installation of the fusible loop are in accordance with API RP 14C recommendation.

The charge panel will regulate and meter a fix amount of instrument air to the fusible loop. During a fire, the heat generated by the fire will melt one or more of the fusible plug located in or near the fire. The ‘melting’ of the plug will cause a release of air from fusible loop through the plug. Since the release of this regulated air exceeds the amount of regulated/metered air supply, the pressure in the loop will decrease significantly. This decrease in pressure is monitored by a pressure switch on the charge panel. The signal from the switch is then utilized to signal an alarm to the Fire and Gas System. In addition, an additional pneumatic output is tied to the deluge valve pilot valve where it is use to open the deluge valve.

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