Introduction To Print Reading
DOE-HDBK-1016/1-93
INTRODUCTION TO PRINT READING
Grid System
Because drawings tend to be large and complex, finding a specific point or piece of equipment
on a drawing can be quite difficult. This is especially true when one wire or pipe run is
continued on a second drawing. To help locate a specific point on a referenced print, most
drawings, especially Piping and Instrument Drawings (P&ID) and electrical schematic drawings,
have a grid system. The grid can consist of letters, numbers, or both that run horizontally and
vertically around the drawing as illustrated on Figure 2. Like a city map, the drawing is divided
into smaller blocks, each having a unique two letter or number identifier. For example, when a
pipe is continued from one drawing to another, not only is the second drawing referenced on the
first drawing, but so are the grid coordinates locating the continued pipe. Therefore the search
for the pipe contained in the block is much easier than searching the whole drawing.
Figure 2 Example of a Grid
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