The European Community is pledged to reach a situation where there is no technical barrier to trading between the community partners. To this end the Commité European de Normalisation (CEN) committee TC129 — Glass in Buildings was set up. The Working Group WG4 has the specific task of writing a specification for Insulating Glass Units.

The instructions to the committee were that any insulating glass units currently meeting there own national standard should not be disadvantaged, at least in the first instance, by not being able to meet the new specification.

Naturally National views were put forward in the early stages, and there has been a period of intense negotiation, and compromise, before the specification started to take shape.

The current situation is that although not complete, the specification is now taking shape and a series of Round Robin comparisons have been carried out to verify the tests included.