scope:

This Practice designates general requirements for the design and construction of aboveground, welded, cylindrical shell, single-wall, shop-fabricated vessels having an internal and external Maximum Allowable Working Pressure (MAWP) not exceeding 15 psig at the top of the vessel while in normal operating position. An additional Low-Pressure Vessel Specification is required to define options covered herein and other specific requirements considering service (startup, normal operation, upset, shutdown), location, maintenance, etc. The documents listed in Section 2.1 should be used for a complete purchase specification. See PIP VECV1001, PIP VESV1002, and PIP VEDV1003 for vessels having an MAWP in excess of 15 psig.

This Practice is intended for low-pressure vessels capable of being hydrostatically tested in both shop and operating positions. This Practice is not intended for flat-bottom tanks or API-type field-erected storage tanks. Unless approved by Purchaser, this Practice is not to be used for low-pressure vessels that will contain "Lethal Substances" as defined in Footnote 1 of Code Paragraph UW-2. PIP VECV1001, PIP VESV1002, and PIP VEDV1003 apply for vessels that are classified for "Lethal Service" or other highly hazardous chemical services.

Many recognized and generally accepted good engineering construction practices are included herein. However, in light of the many diverse service applications of low-pressure, shop-fabricated vessels, these practices must be employed with engineering judgment and supplemented as appropriate with requirements related to specific materials of construction, service fluids, operating environments, and vessel geometries. Accordingly, provisions of this Practice may be overridden or supplemented by an Overlay Specification (see Section 3 for definition).

Purpose

This Practice describes the general materials, design, fabrication, examination, inspection, testing, and documentation requirements for the construction of lowpressure, welded, shop-fabricated vessels that generally meet the philosophy and requirements of Section VIII, Division 1 of the ASME Boiler and Pressure Vessel Code, henceforth referred to as the Code. However, Code inspection and stamping are not required.