ASME PTB-3:2010 pdf free download – ASME Section VIII – Division 2 Example Problem Manual
4.1.1 Example Problem E4.1.1 – Review of General Requirements for a Vessel Design
a) General Requirements
A plant engineer is tasked with developing a design specification for a new pressure vessel that is to be constructed in accordance with ASME B&PV Code, Section VIII, Division 2 (VIII-2). The VIII-2 Code is being considered because the vessel in question is to be constructed of carbon steel with a specified corrosion allowance and a design pressure and temperature of 1650 psig at 200°F. As part of developing the design specification, the following items need to be evaluated.
b) Scope
1) The vessel may be designed using the design-by-rule procedures of Part 4, using the design-by-analysis rules of Part 5, or a combination of both Parts 4 and 5. Some limitations may apply to either design method.
2) The user of the vessel is responsible for defining all applicable loads and operating conditions that the vessel will be subject to. All loads and conditions must be specified on the User’s Design Specification, see Part 2 paragraph 2.2.
3) A fatigue screening shall be applied to all vessel part designed in accordance with this Division to determine if a formal fatigue analysis is required, see Part 5 paragraph 5.5.2.
c) Minimum Thickness Requirements
Based on product form and process service, the parts of the vessel must meet the minimum thickness requirements presented in Part 4, paragraph 4.1.2.
d) Material Thickness Requirements
Fabrication tolerances must be considered in the design of the vessel components, based on forming, heat treatment and product form.
e) Corrosion Allowance in Design Equations
The equations used in a design-by-rule procedure of Part 4 or the thicknesses used in a design-by-analysis of Part 5 must be performed in a corroded condition. The term corrosion allowance is representative of loss of metal due to corrosion, erosion, mechanical abrasion, or other environmental effects. The corrosion allowance must be documented in the User’s Design Specification.
f) Design Basis
1) The pressure used in the design of a vessel component together with the coincident design metal temperature must be specified. Where applicable, the pressure resulting from static head and other static or dynamic loads shall be included in addition to the specified design pressure. The typical loads that need to be considered in the design of a vessel are shown in part 5, Table 5.1.
2) The specified design temperature shall not be less than the mean metal temperature expected coincidentally with the corresponding maximum pressure.
3) A minimum design metal temperature shall be determined and shall consider the coldest operating temperature, operational upsets, auto refrigeration, atmospheric temperature, and any other source of cooling.
4) All applicable loads and load case combinations shall be considered in the design to determine the minimum required wall thickness for a vessel part, see Part 4, Table 4.1.1.
g) Design Allowable Stress
Specifications for all materials of construction are provided in Part 3, Annex 3.A.