TechArchive

Original article date: February 1999

With the withdrawal of the old British Standards and the integration of the new BS EN standards for copper and copper alloys there is inevitably going to be confusion. For this reason the Copper Development Association has published “Copper and Copper Alloys – Composition Applications and Properties” which explains the new series of BS EN standards – the British implementation of European standards.

Because a large number of national preferences needed to be taken into account against the background of a pan-European agreement to develop tight product standards the new BS EN Standards are more complex than the historic BS standards. As he new standards are published they will be in conflict with the old British Standards. These will therefore be withdrawn as will those of other European countries leaving Europe with one harmonised series of standards published in each country but applicable across all. Examples include BS1400 for castings the BS287x series for wrought materials and the BS143x series covering coppers for electrical purposes.

Materials popularly used from the previous BS standards will or course continue to be available but the new designations should be used. For most materials it is easy to obtain near-equivalents to those included in previous standards but not always. Many materials are similar but have detailed differences such as composition and tolerances. This will require designers who still refer to old standards on old specification drawings to amend these for ordering purposes. The publication also includes a selection of tables giving near-equivalents for the brasses previously included in British Standards.

Manufacturers will be the first to see and feel the impact of the new BS EN standards as they are obliged to produce to the most recent standards. So the withdrawal of the old standards and integration of the new ones will be a commercially-driven transition.

Commencing in the late 1980s drafting of European standards for copper and copper alloys became a major activity for national standards organisations and their industrial partners. BS EN copper alloy standards emerge

Within CEN the work is being done in Technical Committee TC/133 with representation from members of the corresponding BSI Committee NFE/34. Table 1 shows BS historic standard numbers in numerical order and their replacement BS EN standards.

As with many other existing European national standards symbols are based on the ISO compositional system – for example CuZn37 is 63/37 brass. ISO and EN symbols may be identical but the detailed compositional limits are not always identical and cannot be assumed to refer to unique materials. A new numbering system has therefore been developed to offer a more user-friendly (and computer-friendly!) alternative. The system is a six-character alphanumeric series beginning C for copper-based material.

The second letter indicates the product form as shown in Table 2

A three-digit number series in the third fourth and fifth places is used to designate each material. It can range from 001 to 999. Numbers are allocated in preferred groups. The sixth character a letter indicates the copper or alloy grouping.

Materials designations are defined in BS EN 1173. In most product standards materials are available in a choice of material conditions. There may be one or more mandatory properties associated with the particular material condition. For designation purposes the principal mandatory property condition is specified by a letter:

For castings properties are dependent on the casting process used:

Table 1 Listing of old BS standards replaced by BS EN standards

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(*) Where the BS/EN number is not yet available the number is expressed as Technical Committee Number/Work Item Number (ie 133/xx)

Table 2 Second letter in specification

B – materials in ingot form for re-melting to produce cast products

C – materials in the form of cast products

F – filler materials for brazing and welding

M – master alloys

R – refined unwrought copper

S – materials in the form of scrap

W – materials in form of wrought products

X – non-standardised materials

Table 3 Three digit numbering series

• Copper Development Association
• Vin Calcutt
• 01727 731200

February 1999