Page 77 - Estimator's Piping Man-Hour Manual 5E

LOCAL STRESS BELIEVING
Gas or Electric Method—Butt Welds—Nozzle Welds or Any Type of Flange Welds
Carbon Steel Materials
Temperatures to 1400T.
NET MAN HOURS EACH
Standard Extra
Pipe Heavy Pipe SCHEDULE NUMBERS
Size & OD Sizes & OD Sizes
Ins. 3/8 "Thick 1/2 "Thick 20 30 40 60 80 100 120 140 160
2 2.3 2.4 „ .. 2.3 „ 2.4 — .. .. 2.6
2-1/2 2.4 2.5 .. -- 2.4 -- 2.5 -- -- 2.7
3 2.5 2.6 .. 2.5 .. 2.6 „ „ - ! 3.0
Q I/ O 2 6 2 7 2 6 2.7 .. | :*f4
"•"
U it £i
4 2.6 3.0 - „ 2.6 .. 3.0 -- 3.1 «» 3.4
5 3.0 3.2 -- -- 3.0 .. 3.2 -- 3.5 - 3.7
6 3.2 3.6 -- -- 3.2 -- 3.6 - 3.7 4.3
8 3.6 4.0 3.6 3.6 3.6 3.7 4.0 4.3 4.5 4.7 5.0
,
10 3.9 4.3 3.9 3.9 3.9 4.3 4.5 4.8 1 5.0 5.3 5.7
12 4.3 4.7 4.3 4.3 4.5 4.9 5.1 TT 5.8 6.0 6.3

MOD 4.7 5.0 4.7 4.7 5.0 5.3 5.7 6.0 6.4 6.7 7.0
16 OD 5.0 5.4 5.0 5.0 5.4 5.8 6.1 6.6 6.8 7.2 7.8
18 OD 5.4 5.8 5.4 5.6 5.8 6.2 6.6 7.0 7.4 7.8 8.6
20 OD 5.6 5.9 5.6 5.8 6.2 6.6 7.0 7.8 8.1 8.5 9.4
24 OD 6.0 6.2 6.0 6.4 6.8 7.2 7.8 8.6 8.9 9.5 10.6
Pipe Thickness: For Stress relieving butt welds and flange welds, the wall thickness of the pipe
determines the man hours that will apply. For stress relieving nozzle welds, the size and
thickness of the header to which the nozzle is attached determines the man hours that will
apply. For local stress relieving of double extra strong material, use Schedule 160 man
hours.
Man Hours: The total man hours for stress relieving shall be determined as follows:
(1) By computing the total of all welds contained in the complete requirement figure on the basis of local
stress relieving unit man hours;
(2) By totaling all pieces included in the complete requirement which can be full furnace stress relieved as
units, classifying them in their applicable groups, and computing the total man hours.
Whichever of these two methods develops the lower man hours should be used in determining the man
hours for stress relieving.
Valves: Stress relieving may be done by the local stress relieving process, or, unless valves
have been welded into the assembly, the complete fabricated assembly may be full furnace
stress relieved as a unit.
The stress relieving of butt welds joining valves to fabricated assemblies must be man
houred as the man hours covering local stress relieving, even though adjacent assemblies
can be full furnace stress relieved as a unit.
Code Requirements: All welds in piping materials having a wall thickness of 3/4" or greater
must be stress relieved to comply with the requirements of the A. S. A. Code for Pressure
Piping. Man hours shown below the ruled line .in the above schedule cover sizes having a
wall thickness of 3/4" or greater.