DOE-HDBK-1016/2-93
Engineering Fabrication,
ENGINEERING FABRICATION, CONSTRUCTION,
Construction, and Architectural Drawings
AND ARCHITECTURAL DRAWINGS
Rev. 0
Page 5
PR-06
Dimensioning Drawings
For any engineering fabrication, construction, or architectural drawing to be of value, exact
information concerning the various dimensions and their tolerances must be provided by the
drawing. Drawings usually denote dimensions and tolerances per the American National
Standards Institute (ANSI) standards. These standards are explained in detail in Dimensioning
and Tolerancing, ANSI Y14.5M - 1982. This section will review the basic methods of denoting
dimensions and tolerances on drawings per the ANSI standards.
Dimensions on a drawing can be expressed in one of two ways. In the first method, the drawing
is drafted to scale and any measurement is obtained by measuring the drawing and correcting for
the scale. In the second method, the actual dimensions of the component are specified on the
drawing. The second method is the preferred method because it reduces the chances of error
and allows greater accuracy and drawing flexibility. Because even the simplest component has
several dimensions that must be stated (and each dimension must have a tolerance), a drawing
can quickly become cluttered with dimensions. To reduce this problem, the ANSI standards
provide rules and conventions for dimensioning a drawing. The basic rules and conventions
must be understood before a dimensioned drawing can be correctly read.
