Border and Frame:
Borders enclosed via the edges of a trimmed sheet and the frame limiting the drawing space shall be provided along with all sizes. It is recommended such these borders have a least width of 20 mm for size A0 and A1 and a least width of 10 mm for size A2, A3 and A4.
The provision of grid reference system is recommended for each size, in order to allow easy location on the drawing of details, modifications and additions. The number of divisions must be divisible via two and be selected in relation to the complexity of the drawing. It is recommended such the length of any type of side of the rectangles comprising the grid shall not be less after that 25 mm and not more than 75 mm. The rectangles of the grid must be referred to via means of capital letters along one edge and numerals along the other edge. The numbering direction may began at the sheet corner opposite to the title block and be repeated on the reverse sides.