©Copyright Task Force Tips LLC 2015-2020
10
LIZ-030 October 29, 2020 Rev13
5.3 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. Depending on
the nozzle chosen, the Master Foam comes with orifice plates for 0.5%, 1%, 3%, or 6%. Each orifice 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 table gives the nominal rates of foam usage. Accuracy of proportioning is fairly insensitive to nozzle inlet pressure. The graph in
Figure 5.3B gives expected percentages for various inlet pressures.
To install the orifice plate in the nozzle
, simply push it into the
bore at the foam 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.
CONCENTRATE FLOW RATE IN GPM
WATER FLOW
(GPM)
FOAM PERCENTAGE
0.5%
1%
3%
6%
250
1.3
2.5
7.7
16.0
250
1.8
3.5
11.0
22.0
500
2.5
5.1
15.0
32.0
750
3.8
7.6
23.0
48.0
1000
--
10.0
31.0
--
1250
--
13.0
39.0
--
1500
--
16.0
45.0
--
2000
--
20.0
60.0
--
EXAMPLE:
500 gpm of water at 3% uses 15.0 gpm of
concentrate.
FLOW SHOWN ARE NOMINAL. ACTUAL RESULTS MAY
VARY BASED ON BRAND AND CONDITION OF FOAM.
Figure 5.3A
Check For
Desired Percentage
Insert into Inlet
Push On
To Lock
Fold Levers
To Hose
0
1
2
3
4
5
6
7
8
40
60
80
100
120
140
160
NOZZLE INLET P
R
E
SS
U
R
E (P
S
I)
FOAM PE
R
CENT
AGE (%)
NOMINAL 0.5%
AT 100 P
S
I
NOMINAL 1%
AT 100 P
S
I
NOMINAL 3%
AT 100 P
S
I
NOMINAL 6%
AT 100 P
S
I
Figure 5.3B