Conversion Chart
Page 13
April 2017
VAM-UM-00646-EN-04
CONVERSION CHART
The conversion chart provides a series of simplified mathematical formulas to adjust the
graduated scale for changes in pressure (
), and/or specific
gravity (
)
OTE:
N
Special scales can be made to accommodate other pressures, temperatures and
specific gravity
The conversion chart can also be used to adjust the multi-pressure flow scale to indicate
flow rates in applications beyond the parameters stated on the scale
To adjust the pressures beyond (above or below) scale limits:
1 Locate the point at which the brightly colored indicator line intersects the vertical 100
Psig pressure line
2 Divide this reading by the pressure correction factor (f
1
) indicated in
To adjust for changes in temperature:
1 Divide the 100 Psig flow rate reading by the temperature correction factor (f
2
)
To adjust for changes in specific gravity:
1 Establish the square root of the new specific gravity
2 Divide the 100 Psig flow rate reading by the Specific Gravity Correction Factor (f
3
)
Conversion Chart
Determine flow rates using different pressures and temperatures
scfm actual
scfm indicated
f x f x f
(
)
(
)
=
1
3
2
Where:
f
1
= conversion factor for inlet pressure
f
2
= conversion factor for inlet temperature
f
3
= conversion factor for inlet specific gravity
psig
25
50
75
100
125
150
175
200
225
250
BAR
17
35
52
69
86
104
121
138
155
172
kPa
172
345
517
689
862
1034
1207
1379
1551
1724
f
1
1700
1331
1131
1000
0902
0835
0778
0731
0692
0658
f
psig
1
114 7
14 7
=
+
.
.
f
BAR
1
7 914
1 014
=
+
.
.
f
kPa
1
790 857
101 357
=
+
.
.
Table 5: Pressure correction factor
°F
+10
+30
+50
+70
+90
+110
+130
+150
+170
+190
°C
–122
–11
+909
+210
+321
+43
+54
+65
+76
+88
f
2
0942
0962
0981
1000
1018
1037
1055
1072
1090
1107
f
F
2
460
530
=
+ °
f
C
2
273
293
=
+ °
Table 6: Temperature correction factor
f
Sp Gr
3
=
. .
Table 7: Specific gravity correction factor
