Helium - SIAD Società Italiana Acetilene e Derivati
Helium is the second lightest elemental gas after hydrogen: The smallest of all molecules, it has the lowest boiling point of any element.
Helium occurs in the atmosphere in a concentration of approximately five parts per million. Because of the low concentration, commercial extraction from the air is impractical. Fortunately, some natural gas deposits have been found to contain significant amounts of helium. Therefore, all commercial helium is obtained from natural gas deposits, a small fraction of which contain helium in concentrations above 0.3 percent by volume. Most of the helium in the world comes from the natural gas deposits found in the panhandle area of Texas, Oklahoma, Kansas and on the eastern flank of the Rocky Mountains.
Chemical formula: He
Purity level: ≥ 99.998%
Relative density (air = 1): 0.138
Aspect: colourless gas
Odour: odourless gas
Limit of flammability in air: not flammable
Other properties: nontoxic, chemically inert, only slightly soluble in water, high thermal conductivity (five times more than water). It does not become radioactive under irradiation; it remains liquid down to essentially absolute zero so that it is the coldest known substance.
Helium is used in several applications, which are listed below.
In metal fabrication, helium is used:
- to create an inert gas shield and prevent oxidation during welding of metals such as aluminium, stainless steel, copper and magnesium alloys.
In the aerospace industry, helium is used:
- to fuel lighter-than-air aircraft, aerostats/balloons.
In semiconductor manufacturing, helium is used:
- to provide a protective atmosphere for growing germanium and silicon crystals for transistors and lasers.
In the electronics industry, helium is used:
- to create a controlled atmosphere for the manufacture of semiconducting devices
- to provide enhanced thermal conductivity.
Other important applications of helium are:
- for producing optical fibers used in telecommunication cables
- in chemical processing, as a carrier gas, to facilitate analysis of a chemical substance's purity and composition through chromatography
- to trace leaks - or verify the absence of them - in pressure or vacuum systems or pipeline leak testing
- in deep-sea diving, as a carrier gas for oxygen, to facilitate respiration in synthetic breathing mixtures used by deep-sea divers working on scientific investigations, explorations or development of offshore oil and gas resources.
To avoid this harmful effect, producers and customers should follow strict safety guidelines for storage and handling, and consult the helium Material Safety Data Sheet.
Helium supply options and services available to SIAD customers include:
- transport in cylinders, cylinder packs or cylinder trucks
- supply of equipment for the correct use of the gas
- assistance and technical consultancy for the transport, distribution and application of the gas.
Helium can also be supplied:
- in grades 5.5 - 6.0
- in welding mixtures of various proportions
- in special and in calibration mixtures with different compositions, upon request.