The Drainplug® is used in the ENERGY Firecover® (fire box), ENERGY Fireshield® (fire panel), fire protection systems, valves and flanges. The ENERGY Drainplug® is designed and tested to react when it’s exposed to fire. The Drainplug is always open when it’s in service, but when exposed to fire, the internal mass expands and prevents heat transfer through the drain hole.