This Appendix provides guidelines for establishing the appropriate joint efficiency for vessels of welded con- struction. The joint efficiencies are applied in various de- sign formulas which determine either the minimum required design thicknesses of vessel parts or the maxi- mum allowable working pressure for a given thickness.
L-1.2 REQUIREMENTS FOR RADIOGRAPHY Radiography is mandatory for certain vessel services and material thicknesses (UW-11). When radiography is not mandatory, the degree of radiography is optional, and the amount of radiography must be determined by the user or his designated agent (U-2).
Whether radiography is mandatory or optional, the amount of radiography performed on each butt weld to- gether with the type of weld (UW-12) will determine the joint efficiency to be applied in the various design formulas.
L-1.3 APPLICATION OF JOINT EFFICIENCY FACTORS
The longitudinal and circumferential directions of stress are investigated separately to determine the most restrictive condition governing stresses in the vessel.
[SeeUG-23(c).] In terms of the application of joint effi- ciencies, each weld joint is considered separately, and
the joint efficiency for that weld joint is then applied in the appropriate design formula for the component under consideration.
L-1.4 FLOWCHARTS
Figures L-1.4-1andL-1.4-2provide step‐by‐step guide- lines for determining required joint efficiencies for var- ious components. Alternatively, Figures L-1.4-3and L-1.4-4provide guidelines for determining joint efficien- cies for weld categories. Generally, the designer should consider the following points:
(a)Is radiography mandatory due to service or materi- al thickness?
(b)Are weld types mandated? For example,UW-2re- stricts weld types to Types 1 or 2 for Category A and B welds. If not, select appropriate types.
(c)If radiography is not mandatory, the amount of radiography performed is optional. The user or his desig- nated agent shall determine the extent of radiography to be performed, or at his option, may permit the vessel manufacturer to select the extent of radiography.
(d)Does the degree of radiography performed on the Category B weld joints in a cylindrical or conical shell af- fect the joint efficiency used on the Category A weld joints? Remember, the minimum required thickness for a cylindrical or conical shell is calculated separately for the circumferential and longitudinal directions and the larger of these two thicknesses calculated selected.
602
Copyright ASME International (BPVC)
Provided by IHS under license with ASME Licensee=Khalda Petroleum/5986215001, User=Amer, Mohamed
--`,``,``,,`,`,,````,`,``,,,`-`-`,,`,,`,`,,`---
Figure L-1.4-1
Joint Efficiency and Weld Joint Type—Cylinders and Cones
Cylindrical and conical shells
UW-11(a)(1), (a)(2), and (a)(3) E 1.0 Type 1 E 0.9 Type 2 Category A, B, C, and D
butt welds
Yes No
Yes No
Select RT Category B and C
butt welds
Select full RT Category A and D butt
welds UW-11(a)(5)
SRT UW-11(b) Table UW-12,
col. (b)
No RT UW-11(c) Table UW-12,
col. (c)
Full RT
Category A E 1.0 Type 1 E 0.9 Type 2
Categories B and C E 1.0 Type 1 E 0.9 Type 2
SRT UW-11(a)(5)(-b)
Category A E 1.0 Type 1 E 0.9 Type 2
Categories B and C E 0.85 Type 1 E 0.80 Type 2
No RT
Category A E 0.85 Type 1 E 0.80 Type 2
Categories B and C E 0.70 Type 1 E 0.65 Type 2 Full RT mandatory
UW-11(a)
Seamless section
Category C corner joint
Category A E = 1.00 Type 1 E = 0.90 Type 2 E = 0.85 Types 3, 4, 5, or 6
Category C E = 1.00 Type 7
GENERAL NOTES:
(a) Thickness required for longitudinal stress in conical sections is as follows:t = PD/[4 cos (α) (S E+ 0.4P)].
(b) SeeUW-11(a)(4)for Category B and C butt welds in nozzles and communicating chambers equal to or less than NPS 10 and thickness 11/8in. (30 mm) or less.
(c) Type 2 joints not allowed for Category A weld joints forUW-2(c)designs.
(d) Type 2 joints allowed for Category A weld joints forUW-2(b)designs for austenitic stainless steel Type 304.
ASME BPVC.VIII.1-2019 L-1.4
603
Copyright ASME International (BPVC)
Provided by IHS under license with ASME Licensee=Khalda Petroleum/5986215001, User=Amer, Mohamed
Not for Resale, 07/02/2019 13:29:04 MDT No reproduction or networking permitted without license from IHS
--`,``,``,,`,`,,````,`,``,,,`-`-`,,`,,`,`,,`---
Yes
Yes
Yes
Yes No
No
No Select head type UG-32,
UG-34
Full RT mandatory
UW-11(a)
Seamless head
SRT selected UW-11(b)
No RT selected UW-11(c)
Category A butt joints Table UW-12, col. (a)
E = 1.0 Type 1 joints E = 0.9 Type 2 joints
Category A butt welds E = 0.85 Type 1 E = 0.80 Type 2 Category A butt joints
E = 0.70 Type 1 joints E = 0.65 Type 2 joints E = 0.60 Type 3 joints Category A double full
fillet lap joint E = 0.55 UW-11(a)(5)(-b) MET
E = 1.0 UW-11(a)(5)(-b) not MET
E = 0.85 [Note (1)]
NOTE:
(1) SeeUW-12(d)when head-to-shell attachment weld is Type no. 3, 4, 5, or 6.
604
Copyright ASME International (BPVC)
Provided by IHS under license with ASME Licensee=Khalda Petroleum/5986215001, User=Amer, Mohamed
--`,``,``,,`,`,,````,`,``,,,`-`-`,,`,,`,`,,`---
Figure L-1.4-3
Joint Efficiencies for Category A and D Welded Joints in Shells, Heads, or Cones
Yes
Yes
Yes
Full
No
No
No
None UW-11(c) UW-11(a)(5)
Select RT [Note (1)]
RT required by UW-11(a)(2)
Steam UW-11(a)(3)
Lethal UW-11(a)(1) Category A and D Butt Joints
in Shells, Heads, or Cones
No. 2 Select
joint type
Select joint type Select Cat. B
radiography
UW-11(a)(5)(-b) met UW-11(a)(5)(-b) not met Type no. 1
E = 1.0
No. 1
No. 1 No. 2
No. 4 Non-butt joint Spot
UW-11(b)
Cat. A joints E = 1.0 Type 1 E = 0.9 Type 2
Cat. A joints E = 0.85 Type 1 E = 0.80 Type 2
Type no. 1 E = 0.85
Type no. 2 E = 0.8
Type no. 1 E = 0.7
Type no. 2 E = 0.65
Type no. 4 E = 0.55
GENERAL NOTE: Use value ofEobtained fromUW-12in appropriate formulas for circumferential stress or stress on Category A welds, such as
UG-27(c)(1)—cylindrical shells UG-32(c)—ellipsoidal heads UG-32(d)—torispherical heads UG-32(e)—hemispherical heads UG-32(f)—conical heads and sections UG-34(c)(2)—flat heads
NOTE:
(1) SeeUW-11(a)(5)(-b).
ASME BPVC.VIII.1-2019 L-1.4
605
Copyright ASME International (BPVC)
Provided by IHS under license with ASME Licensee=Khalda Petroleum/5986215001, User=Amer, Mohamed
Not for Resale, 07/02/2019 13:29:04 MDT No reproduction or networking permitted without license from IHS
--`,``,``,,`,`,,````,`,``,,,`-`-`,,`,,`,`,,`---
Lethal UW-11(a)(1) in Shells or Cones
Type no. 1 E = 0.85 Yes
Yes
Yes
Yes
Yes
Yes No
No
No
No No No
No
Yes
No. 2 Select
joint type
Select joint type Spot
UW-11(b)
Type no. 1 E = 1.0
Select joint type Select
joint type
No. 2 No. 1 No. 2
No. 1 No. 3 No. 4 No. 6
No. 5 Type no. 2
E = 0.9
Type no. 2 E = 0.8
Type no. 1 E = 0.7
Type no. 2 E = 0.65
Type no. 3 E = 0.6
Type no. 5 E = 0.5 Type no. 4
E = 0.55
Type no. 6 E = 0.45 UW-11(c)
UW-11(a)(5)
No. 1
Full None Butt
joint Select
RT [Note(2)]
NPS > 10
RT required by UW-11(a)(2)
Steam UW-11(a)(3)
Nozzle or communicating
chamber [Note (1)]
GENERAL NOTE: Use value ofEobtained fromUW-12in appropriate formulas for longitudinal stress, such asUG-27(c)(2).
NOTES:
(1) SeeUHT-57(a).
(2) SeeUW-11(a)(5)(-b).
606
Copyright ASME International (BPVC)
Provided by IHS under license with ASME Licensee=Khalda Petroleum/5986215001, User=Amer, Mohamed
--`,``,``,,`,`,,````,`,``,,,`-`-`,,`,,`,`,,`---
ð19ị