The standardisation of inert welding gases is now uniform throughout the world, under the international DIN EN ISO 14175 standard.

Previously, inert welding gases were standardised under the European DIN EN 439 standard. The new standardisation however, sees changes to mix accuracy, permissible moisture content and the main group names.

The new standards are likely to be of particular interest to companies with international operations, who work in areas requiring licenses.

Messer, one of the gas specialists, provides comparison tables on the internet at its site This shows, at a glance, the allocation of products from the Messer range of inert welding gases and provides comprehensive information about the new designations.

In addition to the classification of gases and gas mixtures into main groups, the new designations have also been applied to the mix accuracy, the permissible moisture content and the names of the main groups. In the main groups, the changes only affect the forming gases and special gases. The groups have been renamed 'N' and 'Z'. The group Oxygen or 'O' has also been added.

The maximum permitted moisture content of gas groups 'O' and 'C' has been altered, as the purities used in practice have far exceeded the standard for a number of years. With regard to mix accuracy, no definition has been made for additions of less than 1% and nothing has changed as far as additions of more than 1% are concerned.