supervised control valve in the system piping downstream of the test connection so the system
can be isolated when the foam proportioner is tested. This configuration will allow testing of the
foam proportioner without flowing foam-water solution throughout the system (see Figure 3).
Each test header must be sized for the demand that it serves.
The piping in the trench shall have end caps that are tapped with a valve to allow for
draining the piping after it has been activated and attaching a pressure gage for testing purposes.
The low-level AFFF system, including the Grate NozzleTM, shall be flushed prior to
any testing and after final acceptance.
For AFFF proportioning systems that utilize foam pumps, a test connection shall be
provided to facilitate testing the foam pumps in accordance with NFPA 20.
For testing purposes, the foam system shall be equipped with fittings to accommodate
an auxiliary tank of alternate test liquid to determine foam solution flow and foam solution
concentration utilizing the conductivity method.
Bladder Tank Systems: The foam system, water and foam concentrate supply lines,
shall each be fitted with one 2-inch valved connection to accommodate interconnection of an
auxiliary tank containing an alternate test liquid to be used in place of AFFF for proportioning
system concentration testing. Installation of the valved connection on the foam concentrate
piping shall be at the lowest point and located between the manual and automatic foam
concentrate injection valves.
In-Line Balanced Pressure Pump Type Systems: The foam system shall be fitted with
two (2) additional 2-inch valved connections on the foam concentrate inlet piping to each foam
pump. These connections will be used to interconnect an auxiliary tank containing an alternate
test liquid that can be used in place of foam for future proportioning system concentration
The local environmental regulations must be considered to determine the control
measures for the discharge of the AFFF.
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19 January 2005