- What is the minimum amount of input required to define a tank and satisfy the error check routines?
- Why is the shell course thickness required?
- What does the "Design/Analysis" switch do?
- Must I define the data for all of the shell courses?
- When selecting stainless steel materials from the database, why is the allowable shown as zero in the shell course data grid?
- How is the resisting weight for API-650 Section 5.11 determined?
- Why is a warning generated stating that API-650 Appendix P is intended for tanks more than 120 feet in diameter?
- What is the comparison of API-650 to AWWA D-100?

The basic tank shell is all you need to define. This consists of at least one course height, thickness, and material definition. The temperature, number of courses, fluid height, and fluid density are the remaining parameters you must define.

This thickness is required so the solution mode of the program can be changed from "design" to "analysis" without requiring additional shell course input from the analyst.

The program has two solution modes: design and analyze. In analyze mode, the user's input data is used for all computations. In design mode, the maximum of the required shell course thicknesses from the design and test cases is determined and used in all computations (except the determination of the required shell thickness).

No, only the data for the first course is required. The software will automatically duplicate data for the remaining, undefined courses. Data is duplicated from the last-defined course.

The allowable for stainless steels is interpolated from a table (based on temperature) at run time. The input table shows zero for the allowable, since the actual analysis has not commenced. The interpolated value used as the allowable is printed in the "Material Property" section of the output. The right five columns of this grid show the allowable stress values as a function of temperature. The final allowable value is interpolated from this data set.

The resisting weight is the sum of the corroded shell weight, plus the weight of any shell attachments, plus a percentage of the roof framing and roof. This sum is then reduced by the internal pressure force. (The percent of the roof and framing weight supported by the shell can be determined by the software if a supported cone roof has been selected. If a different roof type was defined, this percentage must be specified by the user.)

Appendix P was written from two technical papers, publishing the findings for two full scale tanks that were instrumented, tested, and verified by finite element analysis. Both of these tanks were more than 120 ft in diameter. The shell curvature of these tanks is much greater than the nozzle diameter, so the behavior is more like a nozzle intersecting a plate instead of a cylinder-cylinder intersection. Tanks much smaller than 120 ft in diameter behave differently (more like a cylinder-cylinder intersection), and the results obtained from Appendix P may not be applicable or accurate.

TANK provides an alternative computation procedure for smaller tanks. This procedure is described in PVP-1279.

Please see the following page for the detailed comparison.