Preaction System with DV-5 Deluge Valve
Single Interlock, Supervised — Wet Pilot Actuation
1-1/2 thru 8 Inch (DN40 thru DN200)
Page 1 of 14 JULY 2014 TFP1410
Worldwide
Contacts
www.tyco-fire.com
General
Description
The DV-5 Supervised Single Interlock
Preaction System with Wet Pilot Ac-
tuation (Refer to Figure 1) utilizes au-
tomatic sprinklers and a supplemental
detection system. The supplemental
detection system is comprised of wet
pilot lines and pilot sprinklers. Actua-
tion of the detection system automati-
cally operates (releases) the DV-5 Del-
uge Valve, allowing water to ow into
the sprinkler piping system and to be
discharged from any sprinklers that
may be open.
In accordance with the requirements
of the National Fire Protection Asso-
ciation, a preaction system employing
more than 20 automatic sprinklers is
to have the sprinkler piping automati-
cally supervised to monitor the overall
integrity of the system. In the case of
a Supervised Single Interlock Preac-
tion System, a Riser Check Valve (that
does not require the use of priming wa-
ter) provides an air check so that the
system can be automatically pressur-
ized with a nominal supervisory air or
nitrogen pressure of 10 psi (0,69 bar). A
supervisory low pressure alarm switch
that is set to transfer its contacts at
nominally 5 psi (0,34 bar), on decreas-
ing pressure, is utilized to indicate
whether there are any abnormal leaks
in the sprinkler system piping. Loss of
air pressure from the system as a re-
sult of a damaged sprinkler or broken
piping will not cause the DV-5 Valve to
open — the air pressure is for supervi-
sory alarm only.
Typically, the system designer selects
the detection components for a single
interlock preaction system that will re-
spond to a re sooner than the auto-
matic sprinklers. Consequently, the
system will experience a minimal de-
lay in water delivery over that for a wet
pipe sprinkler system because the sys-
tem will have essentially lled with wa-
ter before a sprinkler operates. In the
case of wet pilot actuation, the system
designer selects wet pilot sprinklers
that will operate sooner than the auto-
matic sprinklers chosen for use on the
sprinkler piping.
Supervised single interlock preaction
systems are generally used to protect
areas where there is danger of serious
water damage that might result from
damaged automatic sprinklers or pip-
ing. Typically, such areas include com-
puter rooms, storage areas for valuable
artifacts, libraries, and archives.
Single interlock preaction systems are
also effectively used to protect prop-
erties where a pre-alarm of a possible
re condition may allow time for re ex-
tinguishment by alternate suppression
means, prior to a sprinkler discharge.
In the event the re cannot otherwise
be extinguished, the preaction sprinkler
system will then perform as the primary
re protection system.
The DV-5 Deluge Valve (described in
Technical Data Sheet TFP1305) is a
diaphragm style valve that depends
upon water pressure in the Diaphragm
Chamber to hold the Diaphragm closed
against the water supply pressure.
When the DV-5 Valve is set for service,
the Diaphragm Chamber is pressurized
through the trim connections from the
inlet side of the system’s main control
valve, such as an O.S.&Y. gate valve or
buttery valve (Fig. 1).
Opening of a pilot sprinkler, releas-
es water from the Diaphragm Cham-
ber faster than it can be replenished
through the 1/8 inch (3,2 mm) restric-
tion provided by the Model ASV-1
Automatic Shut-Off Valve in the dia-
phragm supply connection (Item 5 -
Fig. 3A, also described in Technical
Data Sheet TFP1384). This results in a
rapid pressure drop in the Diaphragm
Chamber to below the valve trip point.
The water supply pressure then forces
the Diaphragm open, permitting water
to ow into the system piping, as well
as through the Alarm Port to actuate
the system alarms.
As water ows into the system, the pi-
lot chamber of the Model ASV-1 Auto-
matic Shut-Off Valve (Item 5 - Fig. 3A)
becomes pressurized and the ASV-1
automatically shuts off the diaphragm
chamber supply ow to the DV-5 Di-
aphragm Chamber. Shutting off the
diaphragm chamber supply ow pre-
vents the DV-5 Diaphragm Chamber
from becoming re-pressurized, there-
by preventing inadvertent closing of the
DV-5 during a re (as may be the case
if an actuation device other than a pi-
lot sprinkler were to be closed after its
initial operation, for example a remote
manual control station).
Continued on Page 4
To Next Page
Need help?
General
