The Viking LPCB SUREFIRE® SIngle Interlock Preaction TRIMPAC® Model D-3 and D-3B used with the Model E Deluge Valve (A.1), a Viking Easy Riser check valve (F.1), a VFR400 Release Control Panel (G.1) and all associated trim piping form a unique operating system. The system piping is normally dry and pnuematically pressurized to supervise the integrity of the piping, fitting and sprinklers and provide the failsafe operation of the system upon loss of the primary and secondary power supplies. Preaction systems are commonly used to help minimize accidential water damage and still provide fast water discharge during a fire emergency.