21
Installation and Operation Manual
T
Figure 8-5 Foam Injector Position
Main Waterway Check Valves
If the system is to be installed in an apparatus where
potable water sources may need to be isolated from the
possibility of foam contamination, there are a few
methods that can be incorporated into the design of the
apparatus or on the outside of the apparatus.
One of those methods is to install check valves in all
water line locations such as flush lines, where foam
concentrate could drain back into the water pumps or
tanks of the fire apparatus, and where the water piping
that will supply foam solution connects to the apparatus
water pump discharge.
Another method is to install a check valve or other
device between the water pump tank and the suction
inlets to the water pump, or outlets of the hydrant.
These are just a few of the methods that may be
available.
CAUTION: The usage of check valves or other
means of isolation are not to be used as a
substitute for proper flushing of apparatus lines
after usage.
Figure 8-6
Recommended Midship Pump Installation
Flushing System
Depending on the corrosiveness of the foam
concentrates used, or when changing foam
concentrate types or manufacturers, a flushing system
must be installed. Generally all Class B foam
concentrates must be flushed from the system after
usage. Most Class A foam concentrates are less
corrosive and do not require flushing after each use.
See Figure 8-7 for a typical flushing system plumbing
schematic.
Main Waterway
Check Valve
Injection Port (Optional location
on other side of Flowmeter)
Flowmeter
Drain Port
Minimum length of nipple for
2-1/2'' pipe is 12-1/2'' (318 mm).
Refer to Table on Page 20 for
recommended nipple lengths for
different pipe sizes.
Figure 8-7
Foam Concentrate Flushing System Diagram
From Foam
Tank
Foam Strainer
Mounted On Foam
Pump Inlet
Check
Valve
Check
Valve
Flush Water
Shut-Off Valve
From
Fire
Pump
Pump
Suction
Line
Injector Above
Horizontal Plane
Injector Below
Horizontal Plane
DO
DON’T
AccuMax SP
