Restrictors
Ann Suter, Wildland Fire Chemical Systems - MTDC
Flow restrictors are physical barriers inside the tank that can be deployed as needed. Restrictors
decrease the opening area of the gate, slowing the rate of liquid exiting the tank.
Restrictors not deployed
Coverage
Level in
gpc
0.5
1
2
3
4
6
8
250
200
Wind: 3 mph at 310 degrees
150
100
50
0
1000
1150
1300
1450
1600
1750
1900
2050
2200
418 gallons of water dropped unrestricted from 150 feet at 122 knots.
Line
Length
in feet
340
240
190
60
40
10
0
Area in
square
feet
25400
13100
6500
1300
500
100
0
Unrestricted water dropped from a P2V shows higher coverage levels and a more concentrated pattern.
This is due to the higher flow rate.
Restrictors deployed
250
200
Wind: 3.5 mph at 105 degrees
150
100
50
0
1000
1150
1300
1450
1600
1750
1900
418 gallons of water dropped restricted from 154 feet at 134 knots.
2050
2200
Coverage
Level in
gpc
0.5
1
2
3
4
6
8
Line
Length
in feet
590
240
50
0
0
0
0
Area in
square
feet
41300
7600
700
0
0
0
0
When restrictors are deployed the flow rates are lower and the pattern tends to be more spread out with no areas of higher
coverage levels.
Revision Date 12/6/06
asuter@fs.fed.us 406-829-6772