Table 3-5: lift loss from barometric pressure, Table 3-6: lift loss from elevation, Preventive measures – Hale SMR User Manual
Page 49
Stainless Max Series Pumps
3-15
Operating Procedures
Table 3-3: “Baseline NFPA Rating,” on page 3-6, shows the
amount of lift loss as temperatures rise. If there is a marked
loss of suction capacity, the pump may be near cavitation.
Note: When water reaches 95° F( 35° C), you should notice a marked
decrease in lift.
❑
Monitor barometric pressure. NFPA standards sets a baseline
of 29.9”Hg. See Table 3-5: “Lift Loss from Barometric
Pressure.”
❑
Location: The higher the elevation above sea level, the lower
the atmospheric pressure and less lift. See Table 3-6: “Lift Loss
from Elevation.”
❑
Open the throttle
gradually and watch
the pressure gauge and the tachometer, if equipped. An
increase in engine RPM without a corresponding increase in
pressure indicates cavitation.
❑
Use a hard suction hose when pumping from draft and soft
suction hose when pumping from a hydrant.
Preventive Measures
❑
Regularly inspect discharge and suction hoses to check for air
leaks. Air leaks can also cause cavitation.
❑
Consider the size of the suction hose. Table 3-7: “Hose size for
Pump Rating Capacity,” on page 3-16, lists the NFPA pre-
selected hose sizes for each pump-rating capacity. Using the
appropriately sized hose minimizes the occurrence of cavitation.
Table 3-5: Lift Loss from Barometric
Pressure
Barometric Reading
in (mb)
Lift Loss
Head Ft. (mm)
9
.
9
2
)
5
.
2
1
0
,
1
(
e
n
il
e
s
a
B
A
B
F
N
7
.
9
2
)
8
.
5
0
0
,
1
(
2
.
0
)
6
.
0
(
5
.
9
2
)
9
9
9
(
5
.
0
)
5
1
.
0
(
3
.
9
2
)
2
.
2
9
9
(
7
.
0
)
1
2
.
0
(
1
.
9
2
)
4
.
5
8
9
(
9
.
0
)
7
2
.
0
(
9
.
8
2
)
7
.
7
8
9
(
1
.
1
)
3
3
.
0
(
7
.
8
2
)
9
.
1
7
9
(
4
.
1
)
3
4
.
0
(
Table 3-6: Lift Loss from Elevation
Elevation
Feet (Meters)
Lift Loss
Feet (Meters)
0
0
0
,
2
)
0
1
6
(
e
n
il
e
s
a
B
A
B
F
N
0
0
0
,
3
)
4
1
9
(
1
.
1
)
3
3
.
0
(
0
0
0
,
4
)
9
1
2
,
1
(
2
.
2
)
7
6
.
0
(
0
0
0
,
5
)
4
2
5
,
1
(
3
.
3
)
0
0
.
1
(
0
0
0
,
6
)
9
2
8
,
1
(
4
.
4
)
4
3
.
1
(
0
0
0
,
7
)
4
3
1
,
2
(
5
.
5
)
7
6
.
1
(
0
0
0
,
8
)
8
3
4
,
2
(
6
.
6
)
1
0
.
2
(
0
0
0
,
9
)
3
4
7
,
2
(
7
.
7
)
5
3
.
2
(
0
0
0
,
0
1
)
8
4
0
,
3
(
8
.
8
)
8
6
.
2
(