METRIC DESIGN GUIDE
Mechanical/Pipe
Steel pipe and copper tube sizes will not now change. American sizes are used in
many parts of the world and should be designated by nominal mm size. Hard metric
pipe size may be used in the future. ASTM B88M, which gives standard hard metric
copper tube sizes, will not be used until ample product availability can be established.
During transition to metric the following should be on at least the mechanical first
sheet:
"ALL SIZES ARE INDUSTRY STANDARD ASTM A53 PIPE AND ASTM B88
TUBE DESIGNATED BY THEIR NOMINAL MILLIMETER (mm) DIAMETER
EQUIVALENT. SEE CHART BELOW."
Nominal Size
Inch
mm
1/2
15
3/4
20
1
25
1-1/4
32
1-1/2
40
2
50
2-1/2
65
3
80
3-1/2
90
4
100
5
125
6
150
8
200
10
250
12
300
Page 23
PBS-PQ260
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