Specialty gas mixtures


Specialty gas mixtures differ from conventional gas mixtures in the following ways:

  • the manufacturing tolerance for the gas mixture is very low, or
  • the mixture contains several components, or
  • the concentration of the components is very low (<1%), or
  • the components are difficult to handle, rare or hazardous, or
  • the gas mixture needs to be tailored in some other way to the client’s specific needs.

We manufacture speciality gas mixtures using a gravimetric method in line with international standards (ISO 6141, 6142, 6145, 10156, 16664) and good practices (EIGA IGC 39/08, 139/10 and 169/13) to ensure the highest possible quality. Reporting concentrations in such a way allows them to be traced back to international central laboratories, such as NIST and VSL, making them suitable for use in calibration, for instance.

The most commonly used gases in speciality gas mixtures are:

  • Argon, Ar
  • Acetylene, C2H2
  • Nitrous oxide, N2O
  • Ethylene, C2H4
  • Oxygen, O2
  • Helium, He
  • Carbon dioxide, CO2
  • Carbon monoxide, CO
  • Methane, CH4
  • Propane, C3H8
  • Synthetic air, 20.9 % O2 + N2
  • Nitrogen, N2
  • Hydrogen, H2

In addition to these, our extensive in-house development work and collaboration with international partners allows us to offer more than 300 possible components for specialty gas mixtures.

Mixtures in accordance with the ISO 17025 standard

In applications that rely on extreme accuracy and reliability, ISO 17025-accredited mixtures are usually required.

Each component of such mixtures is analysed with an accredited method, making the testing more vigorous than analyses performed by an accredited laboratory. Therefore, it is important to ask a supplier of accredited mixtures for an accreditation certificate for the analysis of each required component.

This is often mistakenly taken to mean the same thing as an analysis performed by an ISO 17025-accredited laboratory. There is, however, a clear difference between the two analysis types.

Woikoski provides mixtures accredited in the correct manner via its international partners.

Hazard classification for specialty gas mixtures

Our specialty gas mixtures are categorised into six classes in accordance with the hazard classification set out in the CLP Regulation (EC 1272/2008). These classes are:

  • Inert
  • Flammable
  • Oxidising
  • Toxic
  • Flammable and toxic
  • Oxidising and toxic

Colour codes on the cylinder necks and valve outlets are determined in accordance with this classification. This helps to ensure that cylinders are as safe to use and store as possible.