64 Chapter 4
ric units, 5/8 inch thick equals 17 mm and 3/4 inch thick equals 20 mm. Using the same method, the
length and width of sheet of plywood change from 48 x 96 inches to 1200 x 2400 mm. In countries that
have adopted the metric system, the dimensioning module is 100 mm, whereas in the United States ar-
chitectural design and construction modules normally used are 12 or 16 inches. Thus, construction
members that are spaced 24 inches on center (O.C.) in the United States translate into 600 mm O.C.
spacing in Canada or the United Kingdom.
Figure 4.6A A drawing of a stair detail drawn to a scale of 1 1/2" = 1'-0".