During operations, Figure f-2: lift loss from temperature, Figure f-3: lift loss from elevation – Hale 80FC User Manual
Page 147: Preventive measures, Figure f-3a: lift loss from barometric reading
147
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 elevation
above sea level, the lower
the atmospheric pressure
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 147.
❑
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 148.
Preventive Measures
❑
Consider the size of the suction hose. Figure F-4: “Hose Size vs. Pump Rat-
ing Capacity” on page 148, 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