Gas Correction Factors for Thermal-based Mass Flow Controllers

The following table lists theoretical gas correction factors for various gases with respect to Nitrogen for thermal-based mass flow controllers. Please note that a non-linearity may exist between a Nitrogen calibration and the actual flow of process gases.

Gas Symbol Specific Heat, CP
cal/g°C
Density
g/l @ 0°C
Conversion
Factor
Air - - - 0.240 1.293 1.00
Ammonia NH3 0.492 0.760 0.73
Argon Ar 0.1244 1.782 1.39
Arsine AsH3 0.1167 3.478 0.67
Boron Trichloride BCl3 0.1279 5.227 0.41
Bromine Br2 0.0539 7.130 0.81
Carbon Dioxide CO2 0.2016 1.964 0.70*
Carbon Monoxide CO 0.2488 1.250 1.00
Carbon Tetrachloride CCl4 0.1655 6.86 0.31
Carbon Tetraflouride
   (Freon - 14)
CF4 0.1654 3.926 0.42
Chlorine Cl2 0.1144 3.163 0.86
Chlorodifluoromethane
   (Freon - 22)
CHClF2 0.1544 3.858 0.46
Chloropentafluoroethane
   (Freon - 115)
C2ClF5 0.164 6.892 0.24
Chlorotrifluoromethane
   (Freon - 13)
CClF3 0.153 4.660 0.38
Cyanogen C2N2 0.2613 2.322 0.61
Deuterium D2 1.722 0.1799 1.00
Diborane B2H6 0.508 1.235 0.44
Dibromodifluoromethane CBr2F2 0.15 9.362 0.19
Dichlorodifluoromethane
   (Freon - 12)
CCl2F2 0.1432 5.395 0.35
Dichlorofluoromethane
   (Freon - 21)
CHCl2F 0.140 4.592 0.42
Dichloromethysilane (CH3)2SiCl2 0.1882 5.758 0.25
Dichlorosilane SiH2Cl2 0.150 4.506 0.40
1,2-Dichlorotetrafluoroethane
   (Freon - 114)
C2Cl2F4 0.160 7.626 0.22
1,1-Difluoroethylene
   (Freon - 1132A)
C2H2F2 0.224 2.857 0.43
2,2-Dimethylpropane C5H12 0.3914 3.219 0.22
Ethane C2H6 0.4097 1.342 0.50
Fluorine F2 0.1873 1.695 0.98
Fluoroform
   (Freon - 23)
CHF3 0.176 3.127 0.50
Freon - 11 CCl3F 0.1357 6.129 0.33
Freon - 12 CCl2F2 0.1432 5.395 0.35
Freon - 13 CClF3 0.153 4.660 0.38
Freon - 13 B1 CBrF3 0.1113 6.644 0.37
Freon - 14 CF4 0.1654 3.926 0.42
Freon - 21 CHCl2F 0.140 4.592 0.42
Freon - 22 CHClF2 0.1544 3.858 0.46
Freon - 23 CHF3 0.176 3.127 0.50
Freon - 113 C2Cl2F3 0.161 8.360 0.20
Freon - 114 C2Cl2F4 0.160 7.626 0.22
Freon - 115 C2ClF5 0.164 6.892 0.24
Freon - 116 C2F6 0.1843 6.157 0.24
Freon - C318 C4F8 0.1866 8.93 0.164
Freon - 1132A C2H2F2 0.224 2.857 0.43
Helium He 1.241 0.1786 1.45
Hexafluoroethane
   (Freon - 116)
C2F6 0.1843 6.157 0.24
Hydrogen H2 3.419 0.0899 1.01
Hydrogen Bromide HBr 0.0861 3.610 1.00
Hydrogen Chloride HCl 0.1912 1.627 1.00
Hydrogen Fluoride HF 0.3479 0.893 1.00
Isobutylene C4H8 0.3701 2.503 0.29
Krypton Kr 0.0593 3.739 1.543
Methane CH4 0.5328 0.715 0.72
Methyl Fluoride CH3F 0.3221 1.518 0.56
Molybdenum Hexafluoride MoF6 0.1373 9.366 0.21
Neon Ne 0.246 0.900 1.46
Nitric Oxide NO 0.2328 1.339 0.99
Nitrogen N2 0.2485 1.250 1.00
Nitrogen Dioxide NO2 0.1933 2.052 **
Nitrogen Trifluoride NF3 0.1797 3.168 0.48
Nitrous Oxide N2O 0.2088 1.964 0.71
Octafluorocyclobutane
   (Freon - C318)
C4F8 0.1866 8.93 0.164
Oxygen O2 0.2193 1.427 0.993
Pentane C5H12 0.398 3.219 0.21
Perfluoropropane C3F8 0.194 8.388 0.17
Phosgene COCl2 0.1394 4.418 0.44
Phosphine PH3 0.2374 1.517 0.76
Propane C3H8 0.3885 1.967 0.36
Propylene C3H6 0.3541 1.877 0.41
Silane SiH4 0.3189 1.433 0.60
Silicon Tetrachloride SiCl4 0.1270 7.580 0.28
Silicon Tetrafluoride SiF4 0.1691 4.643 0.35
Sulfur Dioxide SO2 0.1488 2.858 0.69
Sulfur Hexafluoride SF6 0.1592 6.516 0.26
Trichlorofluoromethane
   (Freon - 11)
CCl3F 0.1357 6.129 0.33
Trichlorosilane SiHCl3 0.1380 6.043 0.33
1,1,2-Trichloro -
1,2,2-Trifluoroethane

   (Freon - 113)
CCl2FCClF2
or  C2Cl3F3
0.161 8.360 0.20
Tungsten Hexafluoride WF6 0.0810 13.28 0.25
xenon xe 0.0378 5.858 1.32
** Consult MKS Instruments
Note: Standard pressure is defined as 760 mmHg (14.7 psia). Standard temperature is defined as 0°C.

Find gas correction factors for ionization vacuum gauges here.

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