Technical data

1.4 Non Interlock Preaction System
Non-interlock preaction systems combine the operational features of a single interlock preaction system and
a dry system. Non-interlock systems are fully actuated by either a signal from a detection system (same as a
single interlock system) OR from loss of pneumatic pressure (same as a dry system). A solenoid valve and a
Dry Pilot Actuator are connected to the Deluge Valve push-rod chamber outlet and each is piped indepen-
dently to atmospheric pressure via the drain cup. The solenoid provides a separation between the hydrauli-
cally pressurized push-rod chamber and atmospheric pressure drain tubing. Upon receipt of a signal from
the electric detection system, the release panel energizes (opens) the solenoid valve. Pressure is released
from the push-rod chamber allowing the 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 protected area will be activated similar to a wet pipe
system. The Dry Pilot Actuator provides a second separation between the hydraulically pressurized Deluge
Valve push-rod chamber and system pneumatic pressure. Loss of pneumatic pressure in the system due to
a sprinkler opening operates the Dry Pilot Actuator which vents to a drain, relieving hydraulic pressure from
the push-rod chamber and allowing the Deluge Valve to open and flow water into the protected area. Alarm
devices are activated upon the flow of water into the sprinkler system. Pneumatic pressure can be provided
from a tank-mounted air compressor, plant air system, nitrogen cylinders, or nitrogen generator, and must be
regulated with a Reliable Model A-2 Air Maintenance Device. Pneumatic pressure in the system is monitored
by a pressure switch that will provide indication of falling pressure due to leaks or failure of the compressed
gas system. When properly adjusted, the low pressure alarm will activate in advance of the dry pilot actuator,
allowing the owner an opportunity to correct problems with the pressurizing system before the Deluge Valve
opens. The Reliable Non-Interlock Preaction System is derived by adding the non-interlock trim option to the
Reliable Model EX or DDX-LP dry system, and operates with pneumatic pressure between 8 and 28 PSI de-
pending on the pressure of the incoming water supply.
Approvals and technical data for the Non-Interlock Preaction System can be found on Reliable Automatic
Sprinkler Company Bulletins 358 & 359 (EX) and 337 & 338 (DDX-LP).
18.
Figure 16