Liquid Helium

Colorless, odorless, inert, non-corrosive, extremely cold, and nonflammable.

CAS Number 7440-59-7

UN Number 1963

Shipping Name Helium, Refrigerated Liquid

Hazard Class 2.2

Label Nonflammable Gas

Applications

Used as a cryogenic refrigerant; it is produced commercially for use in superconducting properties of magnets in applications, such as MRI, NMR spectroscopy and particle physics research. Gaseous helium is used for inert shielding gas in metal arc and laser welding. Helium provides a protective atmosphere in the production of reactive metals, such as titanium and zirconium. It is also used as a coolant during the drawing of optical fibers, as a carrier gas for chromatography and as a leak detection gas in variety of industries, and to inflate balloons and airships

Physical Properties

Chemical formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . He

Molecular weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0026

Specific gravity (Air = 1)

70°F (21.1°C) 1 atm . . . . . . . . . . . . . . . . . . . . . . . . . 0.13796

Density lb. per cu. ft.

70°F 1 atm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ….. 0.01034

Specific Volume, cu ft

per lb 70°F 1 atm . . . . . . . . . . . . . . . . . . . . . . . . . . . … 96.71

Density of saturated vapor (1 atm)

lb/cu ft, 1 atm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0434

Normal boiling point . . . . . . . . . . . . . . . . . . . . . . . . . . -452.1° F

Heat vaporization, BTU/lb . . . . . . . . . . . . . . . . . . . . . . . . . . 9.0

Critical pressure

Absolute atmospheres . . . . . . . . . . . . . . . . . . . . . . . . . . 2.26

Absolute psi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.2

Critical point temperature . . . . . . . . . . . . . . . . . . . . . . -450.1° F

Triple point pressure

Absolute atmospheres . . . . . . . . . . . . . . . . . . . . . . . . 0.1238

Absolute psi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.819

Triple point temperature

Specific heat, BTU/lb, °F . . . . . . . . . . . . . . . . . . 1.2404 @ 70°F

At constant pressure (1 atm) 70°F (21.1°C) . . . . . . . . . . . . . .

At constant volume (1 atm) 70°F (21.1°C) . . . . . . . . . . . . . . .

Ratio of specific heats at . . . . . . . . . . . . . . . . . . 1.6671 @ 70°F

70°F (21.1°C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Coefficient of viscosity, micropoises . . . . . . . . . . . . . . . . 198.5

70°F (21.1°C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178.7

Thermal conductivity, . . . . . . . . . . . . . . . . . . . 0.08266 @ 40°F

32° F (0°C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

BTU/ (sq ft) (hr) (°F)/ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ionization potential, volts . . . . . . . . . . . . . . . . . . . . . . . . . 24.5

Excitation potential, first resonance potential, volts . . . . . 20.91