Barry Millet

ASME Pressure Vessel Internals and Their Design Code

It is common for designers to use the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME) when designing vessel internals (i.e. process trays, bed supports, bolted connections, etc). Typically the ASME allowables are directly applied to internals without any regard to the member geometry or failure modes. The ASME code was developed for modes of failures experienced in the pressure boundary and was not intended to be utilized for the design of structural components. ANSI/AISC 360-10 “Specification for Structural Steel Buildings” (AISC) addresses the failure mechanisms experienced in structures based on their geometry and boundary conditions. This paper will provide several examples along with a direct comparison between structural members designed to the AISC and ASME codes. This paper will also provide guidance for using the AISC methodology with material properties at design temperature from ASME Section II Part D for robust design of internal structures.Copyright

Use of Laser Measurement Systems for Out-of-Roundness Check of ASME BVP Section VIII Div.1 Pressure Vessels

Since the 1956 Edition of the ASME Boiler and Pressure Vessel Code Section VIII (ASME B&PV Code) [1], the Out-of-Roundness of circular sections of pressure vessels subject to external pressure have been inspected using a segmental template per paragraph UG-80(b)(2). Newly approved ASME Code Case 2789 “Laser Measurement for Out-of-Roundness Section VIII, Division 1” to the ASME B&PV Code expands the out of roundness checking to allow the use of laser measurement systems. Today with large vessels approaching 60 feet (18.2 m) in diameter, laser measuring systems allow an expeditious and cost effective method of inspection for out-of-roundness.The Code Case allows the fabricator to use measurements obtained from laser measuring to either verify the vessel in the arc segments or the entire vessel circumference is held to a circularity tolerance. The second option is similar to the requirements of European Standard EN 13445 (EN 13445) [2] which uses circularity.This paper will explore the origin and objective of the template and presents how laser measuring systems make use of the latest technology available to check for out-of-roundness. The paper will address laser measuring systems, procedures for taking measurements, and processing of the data into a format that can be verified by Authorized Inspectors.Copyright

Comparison of Pressure Vessel Codes ASME Section VIII and EN13445

This paper consists of a comparative study of the primary technical, commercial, and usage differences between the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section VIII and the European Pressure Vessel Code EN13445 (EN). This study includes a review of “Comparative Study on Pressure Equipment Standards” (hereby referenced by the “EC Study”) [see REF-1] and provides technical comparisons between the code design requirements, material properties, fabrication, and contributing effects on overall cost. This study is intended to provide a broad viewpoint on the major differences and factors to consider when choosing the most appropriate vessel design code to use.Copyright

Transient Thermal Finite Element Analysis Based on Field Measured Data and the Impact on Fatigue

Many vessels experience significant thermal loads in operation. This paper discusses a method used to develop the internal thermal boundary conditions (film coefficients) required to evaluate thermal loads when the thermal properties of the internal fluid are unknown. In a thermal analysis it is critical to determine the correct film coefficients to achieve the proper behavior. Improperly quantified heat up rates can have a dramatic effect on the overall design. An example is provided to show how assumptions on thermal input can directly effect the results. The method described in this paper uses Finite Element Analysis (FEA) to determine internal film coefficients based on field measured thermocouple data.© 2004 ASME