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ASME PTB-5-2013 — ASME Section VIII Division 3 Example Problem Manual
📘 ASME PTB-5-2013, the Section VIII Division 3 Example Problem Manual, is a technical publication prepared by Daniel T. Peters and colleagues at Structural Integrity Associates under a project sponsored by the ASME Pressure Technology Codes and Standards (PTCS) through ASME Standards Technology, LLC (ST-LLC); it was issued on March 29, 2013. The manual provides example problems illustrating the use of the analysis methods in ASME B&PV Code, Section VIII, Division 3 (VIII-3), the analysis-design route for very-high-pressure equipment, covering materials, elastic-plastic analysis, fatigue, fracture mechanics, autofrettage, openings, and closures. All paragraph references are to the 2010 edition of VIII-3 with the 2011 Addenda [1].
💡 VIII-3 is an analysis-based design route with complex, multi-step procedures. PTB-5 translates Code provisions into step-by-step, reproducible calculations, helping engineers understand the calculation logic and data flow of each paragraph.
1. Scope and Organization 📌
The manual body has two parts: Part 2 introduces the example problems and the rules for their use (calculation precision, table conventions); Parts 3 through 13 correspond to the VIII-3 chapters, with paragraph references to the 2010 edition plus 2011 Addenda. Example problems follow the “E-KX-X.X.X” numbering scheme, e.g., E-KD-2.1.1 denotes the first example of Section 1 of Chapter KD-2 (design).
The correspondence between manual parts and Code chapters is:
| Manual Part | VIII-3 Chapter | Topic |
|---|---|---|
| Part 3 | KM | Materials (test locations, fracture toughness) |
| Part 4 | KD-2 (elastic-plastic/elastic) | Design pressure, local failure, ratcheting, stress-strain curve |
| Part 5 | KD-3 | Fatigue assessment (leak-before-burst, weld fatigue) |
| Part 6 | KD-4 | Fracture mechanics life assessment |
| Part 7 | KD-5 | Residual stresses in autofrettaged vessels |
| Part 8 | KD-6 | Openings and closure evaluation |
| Part 9 | KD-8 | Residual stress evaluation in dual-layered vessels |
| Parts 10–13 | KT / Appendix E, etc. | Hydrostatic test pressure limits, thick/thin-wall bottom head dimensions, thread load distribution |
⚠️ The manual is not a standalone Code: the calculation steps it demonstrates must be used together with the current edition of VIII-3. Because some VIII-3 procedures reference API 579-1/ASME FFS-1, users should obtain that standard when reviewing the related examples.
2. Overview of the Example Problems 🔧
The manual presents worked examples covering typical design scenarios, for example:
- E-KM-2.1.1: evaluation of test locations for cylindrical forgings per KM-2; E-KM-2.1.2: calculation of fracture toughness from Charpy impact tests (KM-251).
- E-KD-2.1.1 / E-KD-2.1.2: determination of design pressure in monobloc and dual-layered cylindrical vessels.
- E-KD-2.2.1–2.2.3: elastic-plastic analysis, protection against local failure (elastic-plastic), and ratcheting assessment (elastic-plastic stress analysis).
- E-KD-2.2.4: generating a stress-strain curve for elastic-plastic finite element analysis; E-KD-2.3.1/2.3.2: linear elastic stress analysis and protection against local failure (KD-247).
- E-KD-3.1.1–3.1.4: leak-before-burst in cylindrical vessels, weld fatigue assessment (elastic analysis and structural stress), and a non-welded vessel using design fatigue curves.
- E-KD-4.1.1: determining the design life of a vessel from E-KD-2.1.1 by fracture mechanics; E-KD-5.1.1/5.1.2: residual stresses in an autofrettaged cylinder wall with known pressure, and determining the autofrettage pressure from known ID tangential residual strain.
💡 Learning path: read Part 2 (“rules of use”) first, then redo the examples in the order “closed-form method → finite element method.” Only when you can reproduce the intermediate coefficients and final results independently have you truly mastered that calculation flow.
Calculation Precision and Data Flow
Paragraph 2.2 addresses calculation precision explicitly: different examples retain different numbers of significant figures for intermediate quantities such as stress intensity factors, the C* parameter, and fatigue damage factors, and this directly affects the final assessment conclusion. When reworking an example, users should keep the same significant figures and rounding convention as the manual, and apply the same numerical strategy in subsequent finite element verification. Meanwhile, the tables of the manual (para. 2.3) uniformly present the input parameters, intermediate results, and final conclusions so that each can be traced back to the corresponding Code paragraph.
Where material data are incomplete, the manual advises users to supplement the VIII-3 material tables with data from pressure vessel research publications or Code appendices. When a calculation procedure of API 579-1/ASME FFS-1 is invoked, particular care is needed with its definitions of material property lower bounds and safety factors, so that nominal stresses obtained from an elastic-plastic analysis are not used directly in a fracture assessment without adjustment.
In a design review team, PTB-5 can also serve as a “library of benchmark examples”: designers archive the worked examples for typical cases first, then use them to quickly validate new geometry and load combinations, improving review efficiency and reducing the probability of manual calculation errors.
3. Engineering Practice Essentials 🛠️
- 🔍 Precision convention: the manual documents calculation precision (para. 2.2); keep enough significant digits in intermediate steps to avoid premature rounding errors.
- 📊 Version check: confirm the VIII-3 edition and addenda year in use; paragraph renumbering changes the steps of the examples.
- 📋 Companion standards: note references to API 579-1/ASME FFS-1 for local-failure and flaw-evaluation procedures, and obtain that standard for re-calculation.
- 🧮 FE modeling: the elastic-plastic examples illustrate stress-strain curve generation; use real material constitutive data as shown, not idealized elastic-perfectly-plastic assumptions.
🚨 A common misuse: copying the example’s input parameters verbatim into your own design without substituting actual material, diameter, and pressure data — or treating an example’s “conclusion” as a general design outcome. The value of an example lies in the method, not the numbers.
4. Frequently Asked Questions ❓
❓ Q: How does PTB-5 relate to the example manuals for VIII-1/VIII-2?
A: The PTB series pairs with the Code volumes (e.g., PTB-1 pairs with VIII-2). PTB-5 specifically supports Section VIII Division 3 (analysis design, very-high-pressure vessels), with chapters matching the KD/KM/KT articles.
A: The PTB series pairs with the Code volumes (e.g., PTB-1 pairs with VIII-2). PTB-5 specifically supports Section VIII Division 3 (analysis design, very-high-pressure vessels), with chapters matching the KD/KM/KT articles.
❓ Q: Why does VIII-3 need a dedicated example manual?
A: VIII-3 uses refined, failure-mode-based design by analysis involving elastic-plastic, fatigue, fracture mechanics, and autofrettage flows that differ greatly from the formula-based design of VIII-1; worked examples significantly reduce learning and review cost.
A: VIII-3 uses refined, failure-mode-based design by analysis involving elastic-plastic, fatigue, fracture mechanics, and autofrettage flows that differ greatly from the formula-based design of VIII-1; worked examples significantly reduce learning and review cost.
❓ Q: Do the examples have legal force?
A: No. PTB-5 is a technical publication, not Code text; following an example does not equal Code compliance. Conformance is determined by the current VIII-3 requirements.
A: No. PTB-5 is a technical publication, not Code text; following an example does not equal Code compliance. Conformance is determined by the current VIII-3 requirements.
🔍 Q: Why do some examples cite API 579-1/ASME FFS-1?
A: Certain VIII-3 assessment procedures (e.g., flaw evaluation, local-failure criteria) adopt the calculation methods of that joint standard by explicit reference, so the manual recommends having it available for re-calculation.
A: Certain VIII-3 assessment procedures (e.g., flaw evaluation, local-failure criteria) adopt the calculation methods of that joint standard by explicit reference, so the manual recommends having it available for re-calculation.
