European Units of Measurement Directives - Directive 71/354/EEC

Directive 71/354/EEC

When the first units of measurement directive was issued, the six members of the EEC had been using the metric system for a hundred years or more. During that time the metric system had undergone a number of changes, particularly in science and engineering. Some industries were based on the cgs variant of the metric system and other on the mks variant. In 1960, the CGPM published the International System of Units (SI), a coherent version of the metric system based on the mks variant. Directive 71/354/EEC sought to rationalise the system of units within the EEC by standardising on SI.

The directive catalogued the units of measure that were permitted for measuring instruments (for instance scales), measurements and indications of quantity expressed in units for economic, public health, public safety and administrative purposes. The catalogue was consistent with the SI standard. The directive explicitly proscribed a number of mainly cgs units of measure that were not to be used after 31 December 1977.

The directive explicitly exempted member states from having to use those units of measure in the catalogue in situations where other units of measure had been laid down by international intergovernmental conventions or agreements in the field of air and sea transport and rail traffic.

Denmark, Ireland and the United Kingdom joined the EEC in 1973. The directive had little impact in Denmark which was in a similar situation to the other EEC member vis-à-vis the use of metric units. Ireland and the United Kingdom were in the process of metrication programmes and the directive was consistent with those countries policies as they stood at the time. The three new member states had five years to implement this directive (as well as all other directives that had been published by the EEC).