R. 48, 50, 57
(c) The scale of the drawings and their graphical execution shall be such that electronic or photographic reproduction with a linear reduction in size to two-thirds will allow all details to be distinguished without difficulty. If, exceptionally, the scale is given on a drawing, it shall be represented graphically.
(h) The same sheet of drawings may contain several figures. Where figures drawn on two or more sheets are intended to form a single figure, the figures on the several sheets shall be so arranged that the whole figure can be assembled without concealing any part of the partial figures. The different figures shall be arranged without wasting space, preferably in an upright position, clearly separated from one another. Where the figures are not arranged in an upright position, they shall be presented sideways with the top of the figures at the left side of the sheet. The different figures shall be numbered consecutively in Arabic numerals, independently of the numbering of the sheets.
(j) The drawings shall not contain text matter. Where indispensable to understand the drawings, a few short keywords, such as "water", "steam", "open", "closed" or "section on AB", may be included. Any such keywords shall be placed in such a way that, if required, they can be replaced by their translations without interfering with any lines of the drawings.