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ASME International

Section VIII – Division 2 Criteria and Commentary
 N PTB-1

Annotation

Overview

Part 1, paragraph 1.2 defines the scope of coverage for VIII-2. The term scope refers to both the type of pressure equipment being considered in the development of these rules, as well as the geometric scope of the vessel that is stamped with the Certification Mark and U2 Designator as meeting VIII-2.

In accordance with Part 1, paragraph 1.2.1.1, pressure vessels are defined as containers for the containment of pressure, internal or external. This pressure may be obtained from any external source, or by the application of heat from a direct or indirect source, as a result of a process, or any combination thereof.

The manner in which the scope of the standard is described follows very closely to the introduction section of VIII-1. In the following paragraphs, a discussion of requirements is provided only where a significant difference exists between VIII-2 and the scope definition from VIII-1, or where a major change was made from Old VIII-2.

With regard to pressure vessels installed in non-stationary applications, Part 1, paragraph 1.2.1.2.b now permits stamping with the Certification Mark and U2 Designator of VIII-2 vessels installed on motor vehicles and railway cars. This particular application was prohibited in the Old VIII-2. Construction and stamping with the Certification Mark and U2 Designator of VIII-2 vessels in non-stationary applications requires a prior written agreement with the local jurisdictional authority covering operation and maintenance control for a specific service. This operation and maintenance control must be retained during the useful life of the pressure vessel by the user in conformance with the Users Design Specification.

Part 1, paragraph 1.2.1.2.e defines pressure vessels in which steam is generated but which are not classified as Unfired Steam Boilers that require construction in accordance with the rules of Section I or VIII-1. A third category for a vessel that generates steam that may be constructed to VIII-2 was added, paragraph 1.2.1.2.e.3: vessels in which steam is generated but not withdrawn for external use.