During operations, Figure f-2: lift loss from temperature, Figure f-3: lift loss from elevation – Hale RSD User Manual
Page 123: Preventive measures, Figure f-3a: lift loss from barometric reading
123
Appendix F: Cavitation
Hale Products, Inc., Nov.2005, Rev-A
C av it atio n
❑
During Operations
❑
Do not increase pump
speed beyond the speed at
which the pressure ceases
to rise. The higher the ele-
vation above sea level, the
lower the atmospheric pres-
sure and less lift. Lift loss is
in addition to NFPA Baseline
of 2.38 ft. (0.73 meters) at
2,000 (610 meters) of eleva-
tion - see Figure F-3: “Lift Loss from Elevation” on page 123.
❑
Open the throttle gradually and watch the pressure gauge and the tachome-
ter, if equipped. An increase in engine RPM without a corresponding
increase in pressure indicates cavitation.
❑
Monitor the water temperature. Figure F-2: “Lift Loss from Temperature”
shows the amount of lift loss as temperatures rise.
❑
Monitor barometric pressure. NFPA standard sets a baseline of 29.9” Hg.
(See Figure F-3a: “Lift Loss from Barometric Reading.”)
❑
Regularly inspect suction hoses to check for air leaks. Air leaks can also
cause cavitation.
❑
Check suction strainer for blockage or effectiveness. See heading “Strain-
ers:” on page 124.
Preventive Measures
❑
Consider the size of the suction hose. Figure F-4: “Hose Size vs. Pump Rat-
ing Capacity” on page 124, lists the NFPA pre-selected hose sizes for each
pump-rating capacity. Using the appropriately sized hose minimizes the
occurrence of cavitation. An undersized suction hose can lead to cavitation.
Water Temperature
F° (C°)
Lift Losses
Head Ft. (Meters)
60°
(16°)
NFPA Base Line - 2.38 (0.73mm)
70°
(21°)
0.3
(0.09)
80°
(27°)
0.6
(0.18)
90°
(32°)
1.1
(0.34)
100°
(38°)
1.7
(0.52)
110°
(43°)
2.5
(0.76)
Figure F-2: Lift Loss from Temperature
Elevation, Feet (Meters)
Lift Loss, Feet (Meters)
2,000
(610)
NFPA Base Line - 2.38 (0.73mm)
3,000
(914)
1.1
(0.33)
4,000
(1,219)
2.2
(0.67)
5,000
(1,524)
3.3
(1.00)
6,000
(1,829)
4.4
(1.34)
7,000
(2,134)
5.5
(1.67)
8,000
(2,438)
6.6
(2.01)
9,000
(2,743)
7.7
(2.35)
10,000
(3,048)
8.8
(2.68)
Figure F-3: Lift Loss from Elevation
Barometric Reading
in. (mb)
Lift Loss, Head Ft. (Meters)
29.9
(1,012.5)
NFPA Base Line - 2.38 (0.73mm)
29.7
(1,005.8)
0.2
(0.6)
29.5
(999)
0.5
(0.15)
29.3
(999.2)
0.7
(0.21)
29.1
(985.4)
0.9
(0.27)
28.9
(987.7)
1.1
(0.33)
28.7
(971.9)
1.4
(0.43)
Figure F-3a: Lift Loss from Barometric Reading