Model Engineering and Metrication
Council Directive 80/181/EEC of 20 December 1979 on the approximation of the laws of the Member States relating to units of measurement and on the repeal of Directive 71/354/EEC
is an EU directive that basically phases out most imperial measures apart from Appendix one (of something else) which is:Imperial Units Of Measurement Available For Primary Use After 1 October 1995
Some imperial units remain available as the primary system of measurement for certain specific uses, either without time limit or no later than 31 December 1999. The units and their uses are as follows:
a. Imperial units of measurement to be used without time limit.
i. pint for sales of draught of beer or cider and for milk sold in returnable containers;
ii. mile, yard, foot and inch for road traffic signs and for related distance and speed measurements;
iii. foot in aircraft heights and other units used in the field of air and sea transport and rail traffic, which have been laid down in international conventions etc (see Article 2 of Directive 80/181);
iv. nautical mile and knot for sea and air traffic;
v. troy ounce for transactions in precious metals;
vi. acre for land registration
What the legislation means is that if you have something that is for example a 1/4 inch bolt. It has to be described as a 63.5mm bolt, but must not even have as a subsidiary description 1/4 inch. Whereas it is reasonable to have equipment designed with metric units, there is a lot of equipment (old steam trains for example) that are designed with imperial units.
This is a situation in which the drive for bureaucratic uniformity is just silly. Why people have to be forced not to describe a 1/4 inch bolt as such or even to have a ruler with inches on it is beyond me.
In practise this will cause problems within the model engineering and heritage engineering sectors. I have, therefore, tabled a motion
and written to the DTI suggesting a bit of commonsense is used.