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2.5.1 FOAM SELECTION
See figure 2.5.1 for a summary of typical uses for various foam types.
HYDROCARBONS
2.5.2 SETTING FOAM PERCENTAGE
The foam percentage is controlled by an orifice plate that is installed in the nozzle at the mouth of the concentrate
inlet (see figure 2.5.3). The
plate is marked with the percentage and nozzle flow rate. The flow rate on the orifice plate must match the flow
rate marked on the nozzle's baffle. The chart in fig 2.5.2a gives the nominal rates of foam usage. Accuracy of
proportioning is fairly insensitive to nozzle inlet pressure. The graph in figure 2.5.2b gives expected percentages
for various inlet pressures.
To install the orifice plate in the nozzle simply push it into the bore at the concentrate inlet on the nozzle. The
orifice plate has an O-ring to hold it in place.
To remove the orifice plate, hook a small object (such as a screwdriver or Allen wrench) into the hole in the
orifice plate and pull it out. Take care not to damage the orifice. Note: The hole in the 6% orifice plate is big
enough that your finger can be used to pull it out instead of a tool.
WATER FLOW
EXAMPLE: 500 GPM OF WATER AT 3% USES 15.5 GPM OF CONCENTRATE
NOTE: FLOWS SHOWN ARE NOMINAL. ACTUAL RESULTS MAY VARY BASED
ON BRAND AND CONDITION OF FOAM
6
LIQUID FUEL - CLASS B
IGNITED
Fig 2.5.1b Basic Guide to Foam Selection and Use
MASTER FOAM
comes with orifice plates for 0.5%, 1%, 3% and 6%. Each orifice
CONCENTRATE FLOW RATE IN GPM
(GPM)
0.5%
350
1.8
500
2.5
750
3.8
Fig 2.5.2a Concentrate Usage Chart
POLAR SOLVENTS
FOAM PERCENTAGE
1%
3%
3.5
10.8
5.1
15.5
7.6
23.2
TASK FORCE TIPS • 800.348.2686 • www.tft.com
IGNITED
6%
22.3
31.9
47.9
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