Page 68 - Estimators Piping Man Hour Manual

Section One-SHOP FABRICATION 51

MACHINING INSIDE OF PIPE

Built-Up-Ends
Carbon Materials Only

Built Up Ends on Inside
Diameter of Pipe and Fittings
with Weld Metal to Provide for
Machining Inside of Pipe Specified Outside Diameter
Net Man Hours per End of Machined Backing Ring
Standard Double
Extra Strong Extra Strong Net
Size & Sch. Nos. to & Sch. Nos. Size Man Hours
Inches 100 Inclusive 120, 140 & 160 Inches per End
2 or less 0.4 0.6 2 or less 0.5
2-1/2 0,4 0.6 2-1/2 0.5
3 0.4 0.6 3 0.6
3-1/2 0.4 0.7 3-1/2 0.6
4 0.6 0,7 4 0.7
5 0.7 0.8 5 0.8
6 0.7 0.9 6 0.9
8 0.9 1.1 8 1.2
10 1.0 1.3 10 1.7

12 1.1 1.5 12 2.1
HOD 1.3 1.8 14 2.6
16 OD 1.5 2.1 16 3.2
18 OD 1.8 2.4 18 3.9
20 OD 2.1 2.9 20 4.7
24 OD 2.9 3.8 24 7.1

Machining: Man hours for machining the inside of straight pipe are for any taper bore from 10° through 30°
included angle. For machining the ends of bends add 100% to the above man hours. For counterboring (up
to a maximum of 2" in length), add 50% to the above man hours. For machining to a controlled "C"
dimension (as required for power piping critical systems), add 225% to the above man hours.
Cutting and Beveling: Man hours do not include cutting and beveling. See respective tables for these charges.
Built-UpEnds: Man hours for built-up ends are for building up the I.D. of straight pipe, bends or fittings, at the
ends with weld metal and grinding where it is necessary for proper fit of backing rings.