associated trim described herein must
be installed and maintained in com-
pliance with this document, as well as
with the applicable standards of the
National Fire Protection Association,
in addition to the standards of any
other Authorities Having Jurisdic-
tion. Failure to do so may impair the
integrity of the associated devices.
The owner is responsible for main-
taining their fire protection system
and devices in proper operating con-
dition. The installing contractor or
manufacturer should be contacted rel-
ative to any questions.
The 4 and 6 inch (100 and 150 mm)
Model F470 Electric/Pneumatic Dou-
ble Interlock Preaction Systems, as
well as their associated trim, are rated
for use at a minimum service pressure
of 20 psi (1,4 bar) and a maximum
service pressure of 175 psi (12,l bar).
The following is a list of the Technical
Data Sheets for the valves and de-
vices which are required as part of the
Double Interlock Preaction System:
Deluge Valve . . . . . . . . TD116
Swing Check Valve . . . . TD320
Dry Pilot Actuator . . . . . TDl17W
Solenoid Valve . . . . . . . TD119
Manual Control Station . . TD121
Water-flow Pressure Alarm
Switch . . . . . . . . . . . TD213
Low Air Pressure Alarm
Switch . . . . . . . . . . . TD232
The following is a list of the Technical
Data Sheets for additional items which
may be considered for use with the
Double Interlock Preaction System:
Accelerator . . . . . . . . . TD109
System Pressure Maintenance De-
vice (select one)
-Air Pressure Reducing Type
. . . . . . . . . . . . . .
TDlll
-Air Compressor Control Type
. . . . . . . . . . . . . .
TD112
-Nitrogen Press. Reducing Type
. . . . . . . . . . . . . .
TD113
Water Motor Alarm . . . . . TD250
System Design Considerations
The .automatic sprinklers, as well as
the deluge valve releasing panel (au-
tomatic control unit), fire detection de-
vices, manual pull stations, and signal-
ing devices, which are utilized with the
Double Interlock Preaction System
must be UL Listed, ULC Listed, C-UL
Listed, or FM Approved, as applicable.
Because a double interlock preaction
system requires time for a drop in sys-
tem air pressure to occur (in addition
to responding to a separate heat de-
tection system), before it will allow
water to enter the system piping, this
system has characteristics similar to a
dry pipe sprinkler system. Therefore,
the system design considerations for a
dry pipe system are normally applied
to a double interlock preaction system
- including a 30% increase in design
area; quick opening devices for sys-
tem capacities of 500 gallons (1890
litres) or more; a maximum 1 minute
water delivery time for system capaci-
ties of 750 gallon (2850 litres) or more;
and, prohibition of gridded system pip-
ing.
The deluge valve, swing check valve,
and all interconnecting piping must be
located in a readily visible and acces-
sible location and in an area which can
be maintained at a minimum tempera-
ture of 4O’F/4’C.
NOTE
Heat tracing is not permitted for the
deluge valve, swing check valve, or
any of the interconnecting piping.
Heat tracing can promote the forma-
tion of hardened mineral deposits
which can prevent system operation.
Heat tracing can also result in dam-
age to the F470 Deluge Valve Dia-
phragm Assembly.
In planning the installation, consider-
ation must also be given to the dis-
posal of the large quantities of water
which may be associated with draining
the system or performing a flow test.
Installation configuration and clear-
ance dimensions are given in Figure B.
The flanged inlet and outlet connec-
tions are faced and drilled per ANSI
Standard 816.1. The grooved outlet
connection of the F5201 Swing Check
Valve is cut in accordance with
Gruvlok standard .groove specifica-
tions for steel pipe, and they are suit-
able for use with grooved end pipe
couplings that are listed or approved
for fire protection service.
In order to readily perform the System
Inspection Procedure described in the
Care and Maintenance section, it is
recommended that a System Shut-Off
Valve be installed above the Model
F52O/F5201 Swing Check Valve, as
shown in Figure A. The System Shut-
Off Valve should be a listed or ap-
proved (as appropriate) indicating
valve with a supervisory switch to mon-
itor the normally open position.
-3-
System Air Pressure Requirements
Graph B shows the minimum Elec-
tric/Pneumatic Double Interlock Pre-
action System air pressure require-
ment as a function of the water supply
pressure. Use of an automatic air or
nitrogen maintenance device is recom-
mended and may be required by the
Authority Having Jurisdiction.
NOTE
The dew point of the air or nitrogen
must be maintained below the lowest
ambient temperature to which the
Double Interlock Preaction System
piping will be exposed, or as required
by the Authority Having Jurisdiction.
Accumulation of water in the connec-
tion to the Dry Pilot Actuator will
lower the air pressure at which the
Dry Pilot Actuator will open and pos-
sibly prevent proper operation. Also,
introduction of moisture into the sys-
tem piping that is exposed to freezing
temperatures can create ice build up
which could prevent proper operation
of the system.
Friction Loss
The nominal pressure losses versus
flow rate for the 4 and 6 inch (100 and
150 mm) combinations of the Model
F470 Multimatic Valve with either the
Model F520 or F5201 Swing Check
Valve are shown in Graphs A-l and
A-2.
The approximate friction losses, based
on the Hazen and Williams formula
and expressed in equivalent length of
Schedule 40 pipe, are given below for
each size deluge and swing check
valve combination. The equivalent
length of pipe has been calculated on
the basis of the flow rates typically
used with each size system.
SIZE OF c = 100
CM20
VALVES FT. OF PIPE
FT. OF PIPE
4” 18.2 25.5
6’ 26.4
36.9
Valve Trim
The F470 Electric/Pneumatic Double
Interlock Preaction Trim, illustrated in
Figure C, is designed to be used in
addition to the (Wet Pilot) Actuation
Trim shown in Figure D. The combina-
tion of these two trim arrangements
forms the complete double interlock
preaction trim arrangement. Figure C
also illustrates the optional Double In-
terlock Accelerator Trim complete with
Model F311 Accelerator. All of the trim
arrangements are designed for use
with either the 4 or 6 inch (100 or 150
mm) valve arrangements.
Fire Department Connection
When installing a fire department con-
nection per NFPA 13 for preaction sys-
tems, a tee fitting (to accomodate the
supply from the fire department con-
nection) will be required between the
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