What is the Difference Between ASME Section VIII Div1 Div2 and Div3

What is the Difference Between ASME Section VIII Div1 Div2 and Div3

What is the Difference Between ASME Section VIII Div1, Div2, and Div3

ASME Section VIII Div1, Div2, and Div3 are the Pressure Vessel Design Code. In this Code various guidelines, rules, and regulatory requirements for pressure vessel Materials, Design, Fabrication, Examination, Inspection, Testing, Certification, and safety. This Code is may seem to be similar but all have some distinct Difference between ASME Section VIII Div1, Div2, and Div3, So Now in this post, we are going to discuss all differences.

In this Post we have elaborate following :

  1. ASME Pressure Vessel Code Section VIII.
  2. List of Subsections.
  3. ASME Section VIII Div 1.
  4. ASME Section VIII Div 2.
  5. ASME Section VIII Div 3.
  6. Difference Between ASME Section VIII Div1, Div2 and Div3.

ASME Pressure Vessel Code, Section VIII (Rules for construction of pressure vessels)

Most pressure vessels employed in industries today are designed consistent with the ASME BPVC Section VIII, which consists of ordinary codes and rules that a manufacturer is required to follow. More than 60 countries worldwide generally recognize and apply the Boiler and Pressure Vessel Code (BPVC) for pressure vessel design. Boiler and Pressure Vessel Code Section VIII is specifically designed to guide mechanical engineers in designing, constructing, and maintaining PVs operating at either internal or external pressure exceeding 15 PSIG.

ASME Section VIII in itself consists of three divisions, where Division 1 is concentrated on a design-by-rule approach and Division 2 on the design-by-analysis approach. Division 3 is supposed for designing pressure vessels that need internal or external operating at a pressure above 10,000 PSI.

While ASME Section VIII, Division 1 is a design-by-rule approach is most commonly utilized by engineers to size the pressure vessel according to the appliance requirements, it’s quite a conservative approach. The empirical relations and other mandatory and non-mandatory criteria often end in an upscale pressure vessel design.

ASME Section VIII, Division 2 is a design-by-analysis approach that requires more detailed calculations than Division 1. Although this might increase the value of pressure vessel design, it allows pressure vessels to face up to higher stresses.

ASME Section VIII, Division 2 is meant for purpose-specific vessels with an outlined fixed location. Another major difference between Division 1 and Division 2 lies in failure theory. While Division 1 is predicated on normal stress theory, Division 2 is predicated on maximum distortion energy (Von Mises).

The codes mentioned under Section VIII for both divisions also having appendices. These appendices are alternative or supplementary rules that function guidelines since they’re less frequently employed than the most body codes. However, the appendices themselves contain both mandatory and non-mandatory sections regarding the design of the sections.

The mandatory appendices are as important as the code itself and provide alternative rules to the main codes included in the body. At present, there are 40 mandatory appendices included in ASME Section VIII. Non-mandatory appendices aren’t a requirement for ASME certification. However, it is good practice to keep them in mind as they can be particularly helpful in design verification and testing.

A new edition of the ASME BPVC codes is issued every two years, including revisions in interpretations and code cases. A code case is an urgent revision of the ASME code to be included in the current running editions. Currently, the 2015 edition is in practice, while the 2017 edition will be made available to the public by July 2017.

With each remake, the codes are refined to assist pressure vessel manufacturers to suit the applicable regulations and gain operational, cost, and safety benefits. within the future, the codes are likely to be developed considering advances in technologies and therefore the use of advanced materials. for instance, future codes will include detailed recommendations in stress analysis methods, component modeling, and result validation.

LIST OF SECTIONS

Below is the structure for the 2019 Edition of the BPV Code:

• ASME BPVC Section I – This section is for the rules of Construction of Power Boilers

• ASME BPVC Section II – Materials

• Part A – Ferrous Material Specifications

• Part B – Nonferrous Material Specifications

• Part C – This part is specially created for the specifications for Welding Rods, Electrodes, and Filler Metals

• Part D – Properties (Customary)

• Part D – Properties (Metric)

• ASME BPVC Section III – This section is for the rules for the Construction of Nuclear Facility Components

• Subsection NCA – This section defines the General Requirements for Division 1 and Division 2

• Appendices

• Division 1

• Subsection NB – Class 1 Components

• Subsection NC – Class 2 Components

• Subsection ND – Class 3 Components

• Subsection NE – Class MC Components

• Subsection NF – Supports

• Subsection NG – Core Support Structures

• Division 2 – Code for Concrete Containments

• Division 3 – Containment Systems for Transportation and Storage of Spent Fuel and High-Level material

• Division 5 – heat Reactors

• ASME BPVC Section IV – This section defines the Rules for manufacturing of Heating Boilers

• ASME BPVC Section V – Section V is for the Non-destructive Examination

• ASME BPVC Section VI – The section Recommends the Rules for the Care and Operation of Heating Boilers

• ASME BPVC Section VII – This section Recommends the Guidelines for the Care of Power Boilers

• ASME BPVC Section VIII – This section defines the rules for the Construction of Pressure Vessels

• Division 1

• Division 2 – Alternative Rules

• Division 3 – Alternative Rules for Construction of high Vessels

• ASME BPVC Section IX – This section is especially for Welding, Brazing, and Fusing Qualifications

• ASME BPVC Section X – This section defines the Fiber-Reinforced Plastic Pressure Vessels

• ASME BPVC Section XI – Rules for Inservice Inspection of atomic power Plant Components

• Division 1 – This division is for the rules of Inspection and Testing of Components of Light-Water-Cooled Plants

• Division 2 – Requirements for Reliability and Integrity Management (RIM) Programs for atomic power Plants

• ASME BPVC Section XII – This section defines the rules for the development and Continued Service of Transport Tanks including cylindrical horizontal & capsule tanks

• ASME BPVC Code Cases – This section is specially designed for the Boilers and Pressure Vessels

ASME Section VIII Div 1

this division is very important from a design perspective because of the compulsory requirements, specific prohibitions, and impulsive, guidelines for materials, design, fabrication, inspection, and testing, markings and reports, overpressure protection, and certification of pressure vessels having an indoor or external pressure more than 15 psi (100 kPa) all will be done in the division.

pressure vessels are often either fired or unfired. The pressure could also be from external sources, or by the appliance of heating from an indirect or direct source, or any combination thereof.

The Division isn’t numbered within the traditional method (Part 1, Part 2, etc.) but is structured with Subsections and Parts which contains letters followed by variety. The structure is as follows:

• Subsection A – General Requirements

• Part UG – General Requirements for All Methods of Construction and every one Materials

• Materials: UG-4 through to UG-15

• Design: UG-16 through to UG-35

• Openings and Reinforcements: UG-36 through to UG-46

• Braced and Stayed Surfaces: This section defines the UG-47 through to UG-50

• Fabrication: UG-75 through to UG-85

• Inspection and Tests: UG-90 through to UG-103

• Marking and Reports: UG-115 through to UG-120

• Overpressure Protection: UG125 through to UG-140

• Subsection B – Requirements concerning Methods of Fabrication of Pressure Vessels

• Part UW – This section defines the Requirements for Pressure Vessels Fabricated by Welding

• General: UW-1 through to UW-3

• Materials: UW-5

• Design: UW-8 through to UW-21

• Fabrication: UW-26 through to UW-42

• Inspection and Tests: UW-46 through to UW-54

• Marking and Reports: UW-60

• Pressure Relief Devices: UW-65

• Part UF – This section defines the Requirements for Pressure Vessels Fabricated by Forging

• General: UF-1

• Materials: UF-5 through to UF-7

• Design: UF-12 through to UF-25

• Fabrication: UF-26 through to UF-43

• Inspection and Tests: UF-45 through to UF-55

• Marking and Reports: UF-115

• Pressure Relief Devices: UF-125

• Part UB – This section defines the requirements for Pressure Vessels Fabricated by Brazing

• General: UB-1 through to UB-3

• Materials: UB-5 through to UB-7

• Design: UB-9 through to UB-22

• Fabrication: UB-30 through to UB-37

• Inspection and Tests: UB-40 through to UB-50

• Marking and Reports: UB-55

• Pressure Relief Devices: UB-60

• Subsection C – Requirements concerning Classes of Materials

• Part UCS – This section defines the requirements for Pressure Vessels Constructed of Carbon and Low Alloy Steels

• General: UCS-1

• Materials: UCS-5 through to UCS-12

• Design: UCS-16 through to UCS-57

• Low-Temperature Operation: UCS-65 through to UCS-68

1:Fabrication: UCS-75 through to UCS-85

• Inspection and Tests: UCS-90

• Marking and Reports: UCS-115

• Pressure Relief Devices: UCS-125

• Nonmandatory Appendix CS: This section defines the UCS-150 through to UCS-160

• Part UNF – This section defines the requirements for Pressure Vessels Constructed of Nonferrous Materials.

  • General: UNF-1 through to UNF-4

• Materials: UNF-5 through to UNF-15

• Design: UNF-16 through to UNF-65

• Fabrication: UNF-75 through to UNF-79

• Inspection and Tests: UNF-90 through to UNF-95

• Marking and Reports: UNF-115

• Pressure Relief Devices: UNF-125

• Appendix NF: This section defines the characteristics of the Nonferrous Materials (Informative and Nonmandatory)

• Part UHA Requirements for Pressure Vessels Constructed of High steel

• General: UHA-1 through to UHA-8

• Materials: UHA-11 through to UHA-13

• Design: UHA-20 through to UHA-34

• Fabrication: UHA-40 through to UHA-44

• Inspection and Tests: UHA-50 through to UHA-52

• Marking and Reports: UHA-60

• Pressure Relief Devices: UHA-65

• Appendix HA: This section is for the suggestions on the choice and Treatment of Austenitic Chromium-Nickel and Ferritic and Martensitic High Chromium Steels (Informative and Nonmandatory)

• Part UCI – Requirements for Pressure Vessels Constructed of forged iron

• General: UCI-1 through to UCI-3

• Materials: UCI-5 through to UCI-12

• Design: UCI-16 through to UCI-37

• Fabrication: UCI-75 through to UCI-78

• Inspection and Tests: UCI-90 through to UCI-101

• Marking and Reports: UCI-115

• Pressure Relief Devices: UCI-125

• Part UCL – Welded Pressure Vessels Constructed of fabric With Anti Corrosion Integral Cladding, Weld Metal Overlay Cladding, or With Applied Linings are covered in this section.

• General: UCL-1 through to UCL-3

• Materials: UCL-10 through to UCL-12

• Design: UCL-20 through to UCL-27

• Fabrication: UCL-30 through to UCL-46

• Inspection and Tests: UCL-50 through to UCL-52

• Marking and Reports: UCL-55

• Pressure Relief Devices: UCL-60

• Part UCD – This section to define the requirements for Pressure Vessels Constructed of Cast Ductile Iron

• General: UCD-1 through to UCD-3

• Materials: UCD-5 through to UCD-12

• Design: UCD-16 through to UCD-37

• Fabrication: UCD-75 through to UCD-78

• Inspection and Tests: UCD-90 through to UCD-101

• Marking and Reports: UCD-115

• Pressure Relief Devices: UCD-125

• Part UHT is made for the requirements for Pressure Vessels Constructed of Ferritic Steels With Tensile Properties Enhanced by Heat Treatment.

• General: UHT-1

• Materials: UHT-5 through to UHT-6

• Design: UHT-16 through to UHT-57

• Fabrication: UHT-75 through to UHT-86

• Inspection and Tests: UHT-90

• Marking and Reports: UHT-115

• Pressure Relief Devices: UHT-125

• Part ULW is designed to define the requirements for Pressure Vessels Fabricated by Layered Construction

• Introduction: ULW-1 through to ULW-2

• Materials: ULW-5

• Design: ULW-16 through to ULW-26

• Welding: ULW-31 through to ULW-33

2:* Non-destructive Examination of Welded Joints: This section is for the ULW-50 through to ULW-57

• Fabrication: ULW-75 through to ULW-78

• Inspection and Tests: ULW-90

• Marking and Reports: ULW-115

• Pressure Relief Devices: ULW-125

• Part ULT Alternative Rules for Pressure Vessels Constructed of Materials Having Higher Allowable Stresses at coldness

• General: ULT-1 through to ULT-5

• Design: ULT-16 through to ULT-57

• Fabrication: ULT-76 through to ULT-86

• Inspection and Tests: ULT-90 through to ULT-100

• Marking and Reports: ULT-115

• Pressure Relief Devices: ULT-125

• Part UHX – This part defines the rules for Shell-and-Tube Heat Exchangers

• Part UIG – This part defines the requirements for Pressure Vessels Constructed of Impregnated Graphite

• General: UIG-1 through to UIG-3

• Materials: UIG-5 through to UIG-8

• Design: UIG-22 through to UIG-60

• Fabrication: UIG-75 through to UIG-84

• Inspection and Tests: UIG-90 through to UIG-112

• Marking and Reports: UIG-115 through to UIG-121

3:* Pressure Relief Devices: UIG-125

• MANDATORY APPENDICES: 1 through to 44

• NONMANDATORY APPENDICES: A through to NN

ASME Section VIII Div 2 (Alternative Rules)

This division covers the compulsive requirements related to the manufacturing of pressure vessel including specific prohibitions, and nonmandatory guidance for materials, design, fabrication, inspection, and testing, markings and reports, overpressure protection, and certification of pressure vessels having an indoor or external pressure which exceeds 3000 psi (20700 kPa) but 10,000 psi.

The pressure vessel is often either fired or unfired. The pressure could even be from external sources, or by the appliance of heating from an indirect or direct source as a result of a process, or any combination of the 2.

The rules contained during this section are often used as an alternate to the minimum requirements laid call at Division 1. Usually, the Div. 2 rules are more onerous than in Div. 1 with regard to materials, design, and nondestructive examinations but higher design stress intensity values are allowed. Div. 2 has also provisions for the use of finite element analysis to figure out expected stress in pressure equipment, additionally to the traditional approach of design by formula (Part 5: “Design by Analysis Requirements”).

ASME Section VIII Div 3 (Optional rules for the Construction of High-Pressure Vessels)

This division covers the compulsory requirements for the manufacturing & design of the pressure vessel including specific prohibitions, and nonmandatory guidance for materials, design, fabrication, inspection, and testing, markings and reports, overpressure protection, and certification of pressure vessels having an indoor or external pressure which exceeds 10,000 psi (70,000 kPa).

The pressure vessel is often either fired or unfired. The pressure could also be from external sources, by the appliance of heating from an indirect or direct source, process reaction, or any combination thereof.

Difference Between ASME Section VIII Div1, Div2, and Div3

ParametersASME Section VIII Div 1ASME Section VIII Div 2ASME Section VIII Div 3
Code Published Yearless than 1940Year – 1968Year – 1997
Code Pressure limitsup to 3000 psigNo limits; usually more than 600 psigNo limit; usually more than 10,000 psig
Organization StructureGeneral, Construction Type & Material U, UG, UW, UF, UB, UCS, UNF, UCI, UCL, UCD, UHT, ULTGeneral, Material, Design, Fabrication and others AG, AM, AD, AF, AR, AI, AT, ASLike Division 2 KG, KM, KD, KF, KR, KE, KT, KS
Design Safety Factor Design Safety Factor is 3.5Design Safety Factor is 3Based on Yield with reduction factor for yield strength to tensile strength ratio less is than 0.7
Code Design RulesMembrane – Maximum stress Generally Elastic analysis Very detailed design rules with Quality (joint efficiency) Factors. Little stress analysis required; pure membrane without consideration of discontinuities controlling stress concentration to a safety factor of 3.5 or higherShell of Revolution – Max. shear stress Generally Elastic analysis Membrane + Bending. Fairly detailed design rules. In addition to the design rules, discontinuities, fatigue, and other stress analysis considerations may be required unless exempted and guidance provided for in Appendix 4, 5 and 6Maximum shear stress Elastic/Plastic Analyses and more. Some design rules provided; Fatigue analysis required; Fracture mechanics evaluation required unless proven leak-before-burst, Residual stresses become significant and maybe positive factors (e.g. autofrettage)
Experimental Stress AnalysisNormally not requiredIntroduced and may be requiredExperimental design verification but may be exempted
Material and Impact TestingFew restrictions on materials; Impact required unless exempted; extensive exemptions under UG-20, UCS 66/67More restrictions on materials; impact required in general with similar rules as Division 1Even more restrictive than Division 2 with different requirements. Fracture toughness testing requirement for fracture mechanics evaluation Crack tip opening displacement (CTOD) testing and establishment of KIc and/or JIc values
NDT RequirementsNDT requirements may be exempted through increased design factorMore stringent NDT requirements; extensive use of RT as well as UT, MT, and PT.Even more restrictive than Division 2; UT used for all butt welds, RT otherwise, extensive use of PT and MT
Welding and fabricationDifferent types with butt welds and othersExtensive use/requirement of butt welds and full penetration welds including non-pressure attachment weldsButt Welds and extensive use of other construction methods such as threaded, layered, wire-wound, interlocking strip-wound, and others
UserUser or designated agent to provide specifications (see U-2(a)User’s Design Specification with detailed design requirements (see AG-301.1) include AD 160 for fatigue evaluationUser’s Design Specification with more specific details (see KG-310) including contained fluid data, etc with useful operation life expected and others. Designer define
ManufacturerManufacturer to declare compliance in data reportManufacturer’s Design Report certifying design specification and code compliance in addition to data reportSame as Division 2
Professional Engineer CertificationNormally not requiredProfessional Engineers’ Certification of User’s Design Specification as well as Manufacturer’s Design Report Professional Engineer shall be experienced in pressure vessel deSame as Division 2 but the Professional Engineer shall be experienced in high pressure vessel design and shall not sign for both User and Manufacturer
Safety Relief ValveUV StampUV StampUV3 Stamp
Code Stamp and MarkingU Stamp with Addition markings including W, P, B, RES; L, UB, DF; RT, HTU2 Stamp with Additional marking including HU3 Stamp with additional marking denoting construction type; HT, PS, WL, M, F, W, UQT, WW, SW
Hydrostatic Pressure Test1.3 time MAWP1.25 times MAWP1.25 times MAWP

So, all the above are the difference between ASME Section VIII Div1, Div2, and Div3.

If you want to increase the accuracy, efficiency, and productivity of your fabrication works and save your time and cost of fabrication then you can use our various digitals tools that help you in your daily fabrication activity Click here know about our digital tools…

If you want to increase your knowledge by learning from us then you can join our various video course in the field of fabrication, Click here more for details about our courses.


Imran Pinjara

Author of Book " Master in Fabrication Layout Development " Published worldwide. Founder and CEO of Let'sFab Educational Services. More than 8 Years of Professional Experience in Field of Pressure Vessel, Heat Ex changer, Storage Tanks, Piping and other Process Equipment Fabrication Industry. He had worked in many Fabrication Industry from small workshop to MNC Company. He had Completed PGDM in Process Piping Design and Engineering as per ASME B31.3 and Bachelor of Mechanical Engineering.