These specifications indicate the technical conditions which the lamps in question must satis y and the test methods to be used to establis the qualities of the lamps and their interchangeability on a scientific basis both with regard to a particular batch and the whole of the production of a manufacturer, in order to maintain a community of interests between the buyer and the manufacturer.
NBN 47-1956 history
1956NBN 47-1956 Tungsten lamps for general lighting