Double Interlock Preaction System with Electric/Pneumatic Release
Viking Electric/Pneumatic Double Interlocked Preaction Systems utilize a Viking deluge valve controlled by a pneumatic actuator, normally held closed by supervisory pressure maintained in the automatic sprinkler system, AND a normally closed electric solenoid valve (controlled by an approved system control panel with compatible detection system. BOTH the electric detection system must activate AND supervisory pressure must be relieved from the sprinkler system before the deluge valve will open to fill the sprinkler system with water. If the electric detection system (alone) operates due to fire, damage, or malfunction, an alarm will activate but the deluge valve will NOT open. If the sprinkler piping is damaged or a sprinkler is broken or fused, but the detection system has not activated, an alarm will activate but the deluge valve will NOT open.
Electric/Pneumatic Double Interlocked Preaction Systems are commonly used as refrigerated area systems. They are also commonly used where flooding of the pipe can have serious consequences, and where it is important to control accidental water discharge due to damaged sprinkler piping.
Care should be taken because Double-Interlocked Preaction Systems may not produce flow from opened sprinklers as quickly as Single or Non-Interlocked Preaction Systems. Activation of a releasing device alone, or operation of a sprinkler alone, will sound an alarm, but will NOT cause the system to fill with water.