Dry Pilot Actuation - Tyco DV-3 Manual

Page 8 of 20
SYSTEM PIPING WITH OPEN NOZZLES OR SPRINKLERS - NORMALLY DRY
LOW
PRESSURE
ALARM
DRY PILOT
SWITCH
ACTUATOR
DRAIN
LOCAL
MANUAL
CONTROL
AUTOMATIC
STATION
AIR/NITROGEN
MAINTENANCE
DEVICE
CHAMBER SUPPLY
CONTROL VALVE
(NORMALLY OPEN)
Dry Pilot
Actuation
The Dry Pilot Actuation Trim provides
for installation of a detection system
consisting of pilot sprinklers (heat de-
tectors) and manual control stations
interconnected with minimum 1/2 inch
(DN15) steel pipe. The pilot line, which
is to be pressurized with air or nitro-
gen, is connected to the "Dry Pilot De-
tection" connection shown in Figures 7
and 12. Provision must be made for a
5.6 K-factor orifice, Inspector's Test
Connection at the most remote loca-
tion from the DV-3 Valve. Nominal in-
stallation dimensions for Dry Pilot Ac-
tuation Trim are shown in Figure 7.
The Dry Pilot Actuation Trim is pro-
vided with a listed and approved Model
DP-1 Dry Pilot Actuator, which is de-
scribed in Technical Data Sheet
TFP1380. The Actuator is rated for use
at a maximum pilot service pressure of
50 psi (3,4 bar) and a maximum water
supply service pressure of 175 psi
(12,1 bar).
Operation of a pilot sprinkler or open-
DRY PILOT SPRINKLER
DETECTION SYSTEM
(MINIMUM 1/2" PIPE AND
AUTOMATIC SPRINKLERS)
DRAIN
DRAIN VALVE
(NORMALLY
CLOSED)
DIAPHRAGM
CHAMBER
DIAPHRAGM
CONNECTION
SYSTEM SCHEMATIC — DRY PILOT ACTUATION
ing of a manual control station re-
leases pneumatic pressure from the
pilot line. In turn, the Dry Pilot Actuator
opens resulting in a rapid pressure
drop in the Diaphragm Chamber of the
DV-3 Valve, and the force differential
holding the Center Valve Assembly
down in the set position is reduced
below the valve trip point.
Dry pilot sprinklers are to be minimum
5.6 K-factor orifice listed or approved
automatic sprinklers. Manual Control
Stations are to be the Model MC-1
described in Technical Data Sheet
TFP1382.
Graph C shows the "minimum pilot line
service pressure" as a function of the
water supply pressure. The pressure
in the dry pilot actuation system must
be automatically maintained using one
of the following maintenance devices,
as appropriate.
• Model AMD-1 Air Maintenance De-
vice (pressure reducing type), refer
to Technical Data Sheet TFP1221.
• Model AMD-2 Air Maintenance De-
DIAPHRAGM
CHAMBER
PRESSURE
GAUGE
RESTRICTION
MAIN
DRAIN
SUPPLY
WATER
SUPPLY
FIGURE 5
INSPECTOR'S TEST CONNECTION
(AT THE MOST REMOTE
LOCATION FROM THE
DELUGE VALVE
REMOTE
MANUAL
CONTROL
DRAIN
STATION
(WHEN
SPECIFIED)
DELUGE
VALVE
WATERFLOW
ALARM SWITCH
WATER SUPPLY
PRESSURE
GAUGE
MAIN
CONTROL VALVE
(NORMALLY
OPEN)
vice (compressor control type), refer
to Technical Data Sheet TFP1231.
• Model AMD-3 Nitrogen Mainte-
nance Device (high pressure reduc-
ing type), refer to Technical Data
Sheet TFP1241.
NOTES
The dew point of the pilot line air pres-
sure must be maintained below the
lowest ambient temperature to which
the dry pilot actuation system will be
exposed. Accumulation of water in the
pilot line connection to the Actuator will
lower the air pressure at which the
Actuator will open and possibly pre-
vent proper operation. Also, introduc-
tion of moisture into the pilot lines ex-
posed to freezing temperatures can
create an ice buildup which could pre-
vent proper operation of the Actuator.
An air dryer must be installed where
the moisture content of the air supply
is not properly controlled at less than
the required value.
It is recommended that an AMD-3 Ni-
trogen Maintenance Device be utilized
in dry pilot actuation system applica-
tions where the dew point must be
TFP1350
DRAIN
PRESSURE