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ASME Section VIII consists of rules and methods of constructing a pressure vessel. In this post an overview of this rules are presented by engineering design team at deconeq Engineering Group.
The ASME Boiler and Pressure Vessel Code (BPVC), also called ASME section VIII, consists of three divisions.
Division 1, as defined by the code, U-1(a)(3), contains mandatory requirements, specific prohibitions, and nonmandatory guidance for pressure vessel materials, design, fabrication, examination, inspection, testing, certification, and pressure relief. For the scope of this Division, Pressure Vessels are containers for the containment of pressure, either internal or external, limited to 15 psi or 100 KPa (as per scope of Division 1).
The Pressure Vessel can be either fired or unfired. The pressure may be from external source, or by the application of heating from an indirect or direct source, or any combination of them.
This Division is divided into three subsections, mandatory Appendixes, and Nonmandatory Appendixes. Subsection A consists of Part UG, covering the general requirements applicable to all pressure vessels. Subsection B covers specific requirements that are applicable to the various methods used in the fabrication of pressure vessels. It consists of Parts UW, UF, and UB dealing with welded, forged, and brazed methods, respectively. Subsection C covers specific requirements applicable to the several classes of materials used in pressure vessel construction. It consists of Parts UCS, UNF, UHA, UCI, UCL, UCD, UHT, ULW, ULT, and UIG dealing with carbon and low alloy steels, nonferrous metals, high alloy steels, cast iron, clad and lined material, cast ductile iron, ferritic steels with properties enhanced by heat treatment, layered construction, low temperature materials, and impregnated graphite, respectively. Section II, Part D also contains tables of maximum allowable stress values for these classes of materials, except for impregnated graphite.
The Mandatory Appendices address specific subjects not covered elsewhere in this Division, and their requirements are mandatory when the subject covered is included in construction under this Division. The Nonmandatory Appendices provide information and suggested good practices.
Division 2 contains mandatory requirements, specific prohibitions, and nonmandatory guidance for pressure vessel materials, design, fabrication, examination, inspection, testing, certification, and overpressure protection of vessels pressurized with either internal or external pressure exceeding 15 psi or 100 KPa. Similar to Division 1, the Pressure Vessel can be either fired or unfired. The pressure may be from external source, or by the application of heating from an indirect or direct source, or any combination of them. The rules contained in this Division, can be used as an alternative to the minimum requirements specified in Division 1.
Generally the Division 2, is considered more conservative compared to Divition 1, with respect to materials, design, fabrication and testing, and allows for higher stress intensity values. Division 2, allows also for the application of finite element analysis for determination of expected stresses in pressure equipment, in addition to the traditional method of design by formula. Please read more about our Finite Element Analysis services at deconeq Engineering Group here.
Division 3, named Alternative Rules for Construction of High Pressure Vessels, covers the mandatory requirements, specific prohibitions, and nonmandatory guidance for pressure vessel materials, design, fabrication, examination, inspection, testing, certification, and overpressure protection of vessels pressurized with either internal or external pressure exceeding 10,000 psi or 70,000 KPa. Again, similar to preceding divisions, the Pressure Vessel can be either fired or unfired. The pressure may be from external source, or by the application of heating from an indirect or direct source, or any combination of them.