When a BILL OF MATERIALS block is used on a construction drawing, it is placed directly above the title block against the right-hand margin. A bill of materials is a tabulated list of material requirements for a given project. The size of the BILL OF MATERIALS block will depend on the size of the drawing and the number of material items listed. On most construction projects, it is impossible to list all items in a single BILL OF MATERIALS block; therefore, it is omitted from the drawings, and a separate list of materials is prepared by an estimator.

When you are preparing drawings, you will use different types of lines to convey information. Line characteristics, such as widths, breaks in the line, and zigzags, all have definite meanings. Figure 3-23, taken from DoD-STD-100C, shows the different types of lines that should be used on your drawings.

Figure 3-23.-Use of line characteristics and conventions.

Figure 3-23.-Use of line characteristics and conventionsContinued.

The widths of the various lines on a drawing are very important in interpreting the drawing. DoD-STD-100C specifies that three widths of line should be used: thin, medium, and thick. As a general rule, on ink drawings, these three line widths are proportioned 1:2:4, respectively. However, the actual width of each type of line should be governed by the size and the type of drawing.

The width of lines in format features (that is, title blocks and revision blocks) should be a minimum of 0.015 in. (thin lines) and 0.030 in. (thick lines). To provide contrasting divisions between elements of the format, thick lines are required for borderlines, outline of principal blocks, and main divisions of blocks, whereas thin lines are required for minor divisions of title and revision blocks and bill of materials. Use of medium line width for letters and numbers is recommended.

The width of lines drawn with a pencil cannot be controlled as well as the width of lines drawn with pen and ink. However, pencil lines should be opaque and of uniform width through-out their length. Cutting plane and viewing plane lines should be the thickest lines on the drawing. Lines used for outlines and other visible lines should be differentiated from hidden, extension, dimension, or center lines.