The so-called Preferred or Standard Number Series is neither well-known nor often used in the British Aircraft Industry, perhaps because the series has not been published by the British Standards Institution or any other official body. Its use has much to commend it on the grounds of convenience and standardisation. Just as it is necessary for the international comprehension of science to standardise on basic symbols and terminology, so is it sometimes beneficial that numbers themselves should be widely used in the same manner.

The Series is published in France as the Renard Series, and also by the International Standards Association, using rounded off numbers to suit the metric system. The American Standards Association has published an American Standard differing from the I.S.A. table only in so far as certain values are rounded off to reasonable inch figures; included also is a table of more approximate fractional sizes.