The document discusses changes between different versions of the ASME Section VIII Code for pressure vessels. Major changes include introducing two vessel classes - Class 1 and Class 2, with Class 1 having a higher design margin of 3.0 compared to Class 2's 2.4. Reinforcement rules for openings were moved to a new section. Material SA-299 was added and figures were included for expansion joints. Allowable stresses are now based on different tables for each class.

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2. Below appendix has been removed
 Appendix 1-9 : Alternative rules for reinforcement of
openings under internal pressure
 Appendix 1-10 : Alternative method for design of
reinforcement for openings in cylindrical
and conical shells under internal pressure
 The main reason being that they are widely untouched and
don’t cover the requirement properly
 They are updated and moved to Part 4.5 of Section VIII,
Division 2.
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3. UG-36 :openings in pressure vessels – values
are little modified
 For vessel ID 1520 mm (1500) and less half the vessel
diameter but not to exceed 510 mm (500)
 This is Just to match the OD of pipe size in mm
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4. UG-66 Curve B
A new material SA-299 is added
Appendix 5: Expansion joint
Extra figures are added
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5. Div 2
There is a major change
Now there are two classes of vessel
 Class 1 vessels have a Design Margin of 3.0,
which is the same as 2004 Edition
 Class 2 vessels have a Design Margin of 2.4,
which is the same as 2015 Edition
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6. Div 2
There is a major change
Now there are two classes of vessel
 Class 1 vessels have a Design Margin of 3.0,
which is the same as 2004 Edition
 Class 2 vessels have a Design Margin of 2.4,
which is the same as 2015 Edition
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7.  For Class 1 vessels, certification of the User’s
Design Specification is only required if a
fatigue analysis is necessary
 For Class 1 vessels, certification of the
Manufacturer’s Design Report is only required
if Part 5 Design-by-Analysis is used to
determine the pressure thickness
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8.  For Class 2 certification of the User’s Design
Specification and Manufacturer’s Design
Report is required, same as requirement as in
2015 Edition.
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9.  The introduction of Class 1 vessels in Section
VIII, Division 2 will allow U2 Certificate
Holders to design and construct an ASME
vessel with a U2 Certification Designator that
is lighter than a Section VIII, Division 1 vessel
but without all of the additional requirements
of a U2 Class 2 vessel.
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10.  Class 1 Vessel – a vessel that is designed
using the allowable stresses from Section II
Part D, subpart 1, Table 2A
 Class 2 Vessel – a vessel that is designed
using the allowable stresses from Section II
Part D, subpart 1, Table 5A
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11.  To simplify :
 Class 1 Class 2
S is lower of S is lower of
UTS/3 , Yield/1.5 UTS/2.4 , Yield/1.5
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12. Ex for SA 516 Gr 70
UTS = 480 Mpa Yeild = 260 MPa
Class 1 Class 2
S is lower of S is lower of
480/3 , 260/1.5 480/2.4 , 260/1.5
Ie 160,174 200,174
160 174
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UTS
Yield
Class 2 : 67 %
Class 1 : 62 %
ASME Div 1: 53 %
ɛ
σ
Allowable stress comparision

14. Some other changes:
 Adoption of the ASME CA-1 Standard on
“Conformity Assessment Requirements”
 Axial Compressive Stress and Hoop Compression-
Paragraphs 4.4.12.2 (b) and (e), 4.4.12.4 (b) and (c), and 4.4.15
were revised to correct the limits for the compressive stress factors
 Correct Equation 4.4.126 in Paragraph
4.4.12.4
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