moves upward. With the Poppet As-
sembly in the full up position, water
flow is diverted from the Domestic
Flow Passage to the Fire Sprinkler
Flow Passage. After the Poppet As-
sembly has moved to the full up posi-
tion, only a small amount of water is
permitted to trickle through the By-
Pass Restriction to the Domestic Port.
The trickle flow through the By-Pass
Restriction permits automatic resetting
of the F540 Valve, without draining of
the fire sprinkler system, after a sprink-
ler operation or test. When the Manual
Domestic Shutoff Valve is closed, the
By-Pass Restriction allows the Supply
and Domestic Port pressures to equal-
ize and the Poppet Assembly to move
back down to the standby position. The
maximum flow rate through the By-
Pass Restriction, when the F540 Valve
is in the operated position is less than
l/4 GPM (0,9 LPM) for a typical resid-
ual (flowing) pressure of 40 psi (2,8
bar) at the inlet. Consequently, it is not
necessary to take into account the
trickle flow through the F540 Valve By-
Pass Restriction, into the domestic
system, when performing hydraulic de-
sign calculations for the fire sprinkler
system.
The contours of the Poppet Assembly
have been specifically configured to
minimize its upward movement except
under the level of sustained fire sprink-
ler system flow resulting from opera-
tion of a fire sprinkler. However, be-
cause most fire sprinkler systems
contain air pockets, the Poppet As-
sembly will tend to move momentarily
upward if there is a surge in supply
pressure. The momentary opening
and reclosing of the Poppet Assembly
at the Fire Sprinkler Seat will trap a
portion of the pressure increase within
the fire sprinkler system. The trapping
of pressure increases within the fire
sprinkler system will help to reduce the
possibility of a subsequent surge in the
supply pressure from causing the
waterflow detector to signal a false
alarm.
As indicated above, domestic system
usage may reduce the pressure avail-
able to the fire sprinkler system. How-
ever, when utilizing the F540 Valve, it
is not necessary to take into account
the complex hydraulic modeling of the
domestic system, that would otherwise
be required to determine the minimum
possible residual (flowing) pressure
which would be available to the fire
sprinkler system.
For operation of the F540 Valve, it is
only necessary to design the fire
sprinkler system, from the water main
to the most hydraulicaly remote sprink-
ler, to provide a minimum single sprink-
ler flow of 12.5 GPM (47,3 LPM), when
the supply pressure at the main is at its
minimum expected value.
6.0
5.0
1.0
0.9
0.8
0.7
0.6
0.5
0.2
0.1 5 6 7 8910 20 30 40 50
FLOW RATE IN GALLONS PER MINUTE (GPM)
FIGURE C
NOMINAL PRESSURE LOSS VERSUS FLOW
NOTE NOTE
A fire sprinkler water supply connec-
tion to a public water supply is usu-
ally subject to local regulations con-
cerning metering and backflow
prevention requirements. Consult
with the local water authorities con-
cerning local requirements which
may apply to the arrangement of these
components in the fire sprinkler sys-
tem water supply.
A spring loaded check valve is not to
be installed between the F540 Valve
and the fire sprinklers.
Figure A illustrates a typical arrange-
ment using the Model F540 Residen-
tial Domestic Shutoff Valve. The ar-
rangement may need to be modified to
meet the requirements of the authority
having jurisdiction; however, the
Model F540 Residential Domestic
1. The F540 Valve is to be installed
vertically with the Supply Port at the
bottom, the Fire Sprinkler Port at the
top, and the Domestic Port at the
side. It is recommended that a suit-
able clamp be installed along the
water supply riser piping, to provide
support for the weight of the F540
Valve.
2. The maximum water supply service
line is to be 1 inch (25mm).
3. The water supply to the F540 Valve
-3-
Shutoff Valve must be installed in ac-
cordance with the following criteria:
