Technical data

11.
1.2.3 Model DDX Electrical Actuation Single Interlock
Where electrical actuation of the system is preferred over wet or dry pilot lines, or where otherwise re-
quired by project specifications, a listed normally-closed (de-energized) solenoid valve is installed on
the outlet of the Model DDX Deluge Valve push-rod chamber. The solenoid provides a separation be-
tween the hydraulically pressurized push-rod chamber and atmospheric pressure drain tubing. Upon
receipt of a signal from the electric detection system, the release panel opens (energizes) the solenoid
valve. Pressure is released from the push-rod chamber allowing the Model DDX Deluge Valve to open
and fill the system piping in the protected area. Alarm devices are activated upon the flow of water into
the sprinkler system piping. In the event the fire continues to grow, individual fire sprinklers in the pro-
tected area will be activated similar to a wet pipe system. For supervised systems (required when there
are more than 20 sprinklers), pneumatic pressure can be provided from a compressor, plant air system,
or nitrogen cylinders. Pneumatic pressure is monitored by a pressure switch that will initiate a signal
in the event of falling pressure due to sprinkler damage, pipe damage, or failure of the compressed
gas system. The Reliable Model B-SI and Model C-SI Air Compressor Panels are specifically designed
for single interlock preaction systems up to 200 gallon capacity and incorporate an air compressor,
regulator, pressure switch, and output relays in a convenient wall mount cabinet (see section 2.3.1).
Approvals and technical data for Model DDX electric release single interlock preaction systems can be
found on Reliable Automatic Sprinkler Company Bulletin 749.
Figure 9