ASME B31.3-2020
Table 302.3.4 Longitudinal Weld Joint Quality Factor, Ej
No.
Type of
Seam
Type of Joint
Examination
Factor,
Ej
1
Furnace butt weld,
continuous weld
Straight
As required by listed specification
0.60
[Note (1)]
2
Electric resistance
weld
Straight or spiral (helical seam)
As required by listed specification
0.85
[Note (1)]
Straight or spiral (helical seam)
As required by listed specification or
this Code
0.80
Additionally spot radiographed in
accordance with para. 341.5.1
0.90
Additionally 100% radiographed in
accordance with para. 344.5.1 and
Table 341.3.2
1.00
3
Electric fusion weld
(a) Single butt weld
(with or without filler
metal)
(b) Double butt weld
Straight or spiral (helical seam) As required by listed specification
(except as provided in 4 below)
or this Code
0.85
Additionally spot radiographed in
accordance with para. 341.5.1
0.90
Additionally 100% radiographed in
accordance with para. 344.5.1 and
Table 341.3.2
1.00
(with or without filler
metal)
4
Specific specification
API 5L, electric fusion
weld, double butt
seam
Straight (with one or two
As required by specification
seams) or spiral (helical seam) Additionally 100% radiographed in
accordance with para. 344.5.1
and Table 341.3.2
0.95
1.00
NOTE: (1) It is not permitted to increase the joint quality factor by additional examination for joint 1 or 2.
W is equal to 1.0 when evaluating occasional loads, e.g.,
wind and earthquake, or when evaluating permissible
variations in accordance with para. 302.2.4. Application
of W is not required when determining the pressure rating
for the occasional load or permissible variation condition.
It is also not required when calculating the allowable
stress range for displacement stresses, SA, in (d).
For other than occasional loads or permissible variations, W shall be in accordance with Table 302.3.5
except as provided in (f).
(f) Alternative Weld Strength Reduction Factors. A weld
strength reduction factor other than that listed in
Table 302.3.5 may be used in accordance with one of
the following criteria:
(1) Creep test data may be used to determine the
weld joint strength reduction factor, W. However, the
use of creep test data to increase the factor W above
that shown in Table 302.3.5 is not permitted for the
CrMo and Creep Strength Enhanced Ferritic (CSEF)
steels materials, as defined in Table 302.3.5. Creep
testing of weld joints to determine weld joint strength
reduction factors, when permitted, should be full thickness cross-weld specimens with test durations of at
least 1 000 h. Full thickness tests shall be used unless
assessment rules in Appendix W to satisfy the displacement stress range requirements of this paragraph and of
para. 319. A significant stress cycle is defined in para.
W300. When the alternative rules of Appendix W are
applied, the calculations shall be documented in the engineering design.
(e) Weld Joint Strength Reduction Factor, W. At elevated
temperatures, the long-term strength of weld joints may
be lower than the long-term strength of the base material.
The weld joint strength reduction factor, W, is the ratio
of the nominal stress to cause failure of a weld joint to that
of the corresponding base material for an elevated
temperature condition of the same duration. It only
applies at weld locations in longitudinal or spiral
(helical seam) welded piping components. The designer
is responsible for the application of weld joint strength
reduction factors to other welds (e.g., circumferential).
When determining the required wall thickness for
internal pressure in accordance with para. 304, for
each coincident operating pressure–temperature condition under consideration, the product of the basic allowable stress and the applicable weld quality factor, SE, shall
be multiplied by W.
18