Helium

Helium is a colorless, odorless and tasteless inert gas which has no toxic properties. A member of the rare gas chemical family, it is 1/7 as heavy as air. Liquid Helium at -452ºF is the coldest liquefied gas.

The Compressed Gas Association (CGA) specification G-9.1-1992, Type I, Grade D is considered the commercial gaseous helium standard.

Gaseous Helium

(Units in ppm (v/v) unless show otherwise)

Helium Chart

Type II liquid helium, when passed through a 10 micron absolute filter at less than 5.2ºK is pure helium for which no analysis is necessary.

The water content of helium required for any particular grade and application may vary with intended use. If a specific limit is required, it should be specified as a limiting concentration expressed in ppm (v/v) or the dew point equivalent. Also note that the water content of grades 4.5 and higher will be about 10 ppm higher when supplied in Pyrex glass flasks.

The Quality Verification Levels apply only to gaseous helium. Impurity limits for liquid helium are not specified since sufficient technical data and analytical procedures are not available to warrant a definitive quantitative specification. The requirement for insuring that the loaded fluid in a container is liquid helium can be satisfied by analyzing the shipping container vent gas or by demonstrating that the temperature of the loaded fluid is below the hydrogen triple point 13.88K).


Helium Conversion Data

Helium
Weight
Gas
Liquid
Pounds

Kilograms

Cubic Feet
Cubic Meters
Gallons
Liters
Lb
Kg
SCF
Sm3
Gal
L
1 Pound
1
0.4536
96.71
2.736
0.9593
3.631
1 Kilogram
2.205
1
213.2
6.039
2.115
8.006
1 SCF Gas
0.0103
0.00469
1
0.02832
0.009919
0.03754
1 Sm3 Gas
0.3651
0.1656
35.31
1
0.3504
1.3257
1 Gal Liquid
1.0423
0.4728
100.8
2.854
1
3.785
1 L Liquid
0.2754
0.1249
26.63
0.7542
0.2642
1

SCF (standard cubic foot) and SM3 (standard cubic meter) gas measured at 1 atmosphere and 70ºF.

Liquid measured at 0ºF and saturated pressure.

Nm3 (normal cubic meter) gas measured at 1 atmosphere and 0ºC.

All values round to the nearest 4/5 significant numbers.