BS EN ISO 6433:1995, BS 308-1.8:1995..Technical drawings. Item references
BS ISO 7573:1983...Technical drawings. Item list.

Item references shall be placed outside the general outline of the drawing.

Each separate item and complete sub-assembly shall have a reference number.

Identical parts should have the same reference number

The item reference shall be a number, the number may be augmented by Capitals.

Item reference numbers shall be distinguishable from other numbers e.g by making the text size larger than the text used for dimensions and notes.

The reference numbers can also be clearly identifiable by including in balloons

Item reference numbers should be located in vertical or horizontal lines for clarity.

The item reference numbers for clearly grouped items can be combined with one leader.

Technical Drawing - Item lists

The item list ( bill of materials) for an assembly drawing can be located on the drawing or it can be provided on a separate dedicated drawing.

The item list should be clearly identified on the drawing as the Item List.

The item list should be orientated to suit the normal reading direction of the drawing.

As a minimum the item list should include vertical columns with the following headings.

Each item should be listed in a separate row separated by thick or thin lines

The item column should include the item number as shown on the drawing

The description column is for the item designation.  Abbreviations, may be used if they are clear.  a typical description would be Bolt- Size- Grade and the relevant standard.

The quantity is the total quantity for one completed assembly.

The reference column identify parts which are not fully detailed on the assembly drawing.   This may be a detail drawing number, a proprietary part number, a code number or a specification number.

The material column should identify clearly the material.  It may be necessary to refer to a noted if the material can not be identified in a concise manner***

The item list can additionally include other information necessary for the finished product e.g. Supply information, item mass, remarks..

*** not in standard..

Note: The figure above is for guidance ..The column order proportions and general layout are not clearly described in the standard and are therefore probably not important..