The American Institute of Architects provides over 300 label names for the sections, details, legends and text and other layers found in CAD drawings. Label names are made up of an initial and an abbreviation of the layers function or content. Architectural drawings begin with the initial A, civil drawings with a C, electrical with an E, fire protection with an F, interior designs with an I, landscaping drawings with an L, and so on. Abbreviations are usually self-explanatory. For instance, the layer of a CAD document that contains the general text of a mechanical drawing is labeled M-ANNO-TEXT. M for mechanical, and ANNO-TEXT for annotations text.
Each layer in a CAD document must be colored according to the AIA's standards. For instance, all layers of architectural annotations and dimensions are cyan, while layers referring to electrical safety are red.
The lineweight of a layer is also set by AIA standards. For example, as a general rule boundary lines, legends, dimensions and notations use a number 4 pen, while construction lines, walls and border and title block use a number 7 pen. Layers dealing with sewers and drainage pipework and manholes, on the other hand, use a number 11 pen lineweight.