Technical data

TECHNICAL DATA
The Viking Corporation, 210 N Industrial Park Drive, Hastings MI 49058
Telephone: [phone] Technical Services 877-384-5464 Fax: [phone] Email: [e-mail]
PREACTION SPRINKLER
SYSTEM
Page 28
February, 2010
C. Non-Interlock Preaction System (Figures 14a-15c)
The non-interlock preaction system utilizes a Viking deluge valve, which may be opened either by the
fusing of a sprinkler in the sprinkler piping or by the operation of the detection system. The sprinkler
piping contains air or nitrogen under pressure. If the detection system does not operate, the sprinkler
system will operate as a dry pipe system. If the sprinkler piping is broken or the sprinkler operates,
the valve will open and water will flow. If the detection system operates due to fire, damage, or mal-
function, the valve will open, but the water will be contained in the sprinkler piping. The system is
supervised to indicate low air pressure.
1. Electric Release
For electrical actuation of the deluge valve, a tee is installed between the PORV and the pneu-
matic actuator and piped to a solenoid valve to an open drain. (Refer to Figures 14a-14c.)
2. Pneumatic Release
For pneumatic detection in non-interlocked preaction systems, a pneumatic actuator is installed
on the 1/2” tee above the emergency release. (Refer to Figures 15a and 15b.) The pneumatic
release system and sprinkler system supervisory air supply are cross connected. Therefore, with
a loss of air pressure in either the release line or sprinkler piping, the pneumatic actuator opens
(Figure 15c) to vent the priming chamber of the deluge valve faster than the water can be replaced
through the restricted orifice in the priming line connection, thus opening the deluge valve.
When a sprinkler system operates before the detection system, the preaction system piping is
cross connected to the pneumatic release line. The deluge valve will operate the same as before
once the pneumatic actuator opens. A check valve is installed in the cross connection so the reac-
tion to release devices is not delayed by the volume of air in the system piping.