401-405 SERIES
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Some meters, specifically the high flow meters, are calibrated in air. The flow readings must then be
corrected twice. Convert once from air to nitrogen, then from nitrogen to the gas that will be measured
with the meter. In this case, multiply the reading times the ratio of the process gas’ GCF to the GCF of
the calibration gas.
Example:
A meter calibrated in air is being used to flow propane. The reading from the meter is multiplied by the
GCF for propane and then divided by the GCF of air.
20 x (0.3499/1.0015) = 6.9875
To calculate a target setting (20 sccm) to achieve a desired flow rate of propane using a meter calibrated
to air, invert the ratio above and multiply.
20 x (1.0015/0.3499) = 57.2449
Gas Conversion Table for Nitrogen
Rec
#
Gas Symbol GCF Derived
Density
(g/L)
Z
25° C / 1
atm
1 Acetic Acid C
2
H
4
F
2
0.4155 4 2.700 2.0301
2 Acetic Acid, Anhydride C
4
H
6
O
3
0.2580 4 4.173 2.3384
3 Acetone C
3
H
6
O 0.3556 4 2.374 1.7504
4 Acetonitryl C
2
H
3
N 0.5178 4 1.678 1.4462
5 Acetylene C
2
H
2
0.6255 4 1.064 0.9792
6 Air Air 1.0015 1 1.185 1.0930
7 Allene C
3
H
4
0.4514 4 1.638 1.3876
8 Ammonia NH
3
0.7807 2 0.696 0.6409
9 Argon Ar 1.4047 1 1.633 2.1243
10 Arsine AsH
3
0.7592 5 3.186 4.0839
11 Benzene C
6
H
6
0.3057 4 3.193 2.0636
12 Boron Trichloride BCl
3
0.4421 4 4.789 3.6531
13 Boron Triflouride BF
3
0.5431 4 2.772 2.4109
14 Bromine Br
2
0.8007 4 6.532 1.0000
15 Bromochlorodifluoromethane CBrClF
2
0.3684 4 6.759 4.2789
16 Bromodifluoromethane CHBrF
2
0.4644 4 5.351 4.3990
17 Bromotrifluormethane CBrF
3
0.3943 4 6.087 4.1546
18 Butane C
4
H
10
0.2622 2 2.376 1.6896
19 Butanol C
4
H
10
O 0.2406 4 3.030 1.9233
20 Butene C
4
H
8
0.3056 4 2.293 1.6700
21 Carbon Dioxide CO
2
0.7526 1 1.799 1.7511
22 Carbon Disulfide CS
2
0.6160 4 3.112 3.0744
23 Carbon Monoxide CO 1.0012 4 1.145 1.0433
24 Carbon Tetrachloride CCl
4
0.3333 4 6.287 3.6196
25 Carbonyl Sulfide COS 0.6680 4 2.456 2.4230
26 Chlorine Cl
2
0.8451 4 2.898 3.9995
27 Chlorine Trifluoride ClF
3
0.4496 5 3.779 2.8970
28 Chlorobenzene C
6
H
5
Cl 0.2614 4 4.601 2.4954
29 Chlorodifluoroethane C
2
H
3
ClF
2
0.3216 4 4.108 2.5119
30 Chloroform CHCl
3
0.4192 4 4.879 3.5284
31 Chloropentafluoroethane C
2
ClF
5
0.2437 4 6.314 2.9778
32 Chloropropane C
3
H
7
Cl 0.3080 4 3.210 2.0756
33 Cisbutene C
4
H
8
0.3004 4 2.293 1.6672
34 Cyanogen C
2
N
2
0.4924 4 2.127 1.7626
35 Cyanogen Chloride ClCN 0.6486 5 2.513 2.4405
36 Cyclobutane C
4
H
8
0.3562 4 2.293 1.7091
