- Required minimum thickness

- Maximum working pressure

- Hemispherical limit for openings (F&D and Elliptical heads only)

- Reduced thickness requirement for reinforcing in the hemispherical limit (F&D and Elliptical heads only)

- Approximate raw material size (except toriconical), finished weight and volume

- If stress relief is required

- Useful dimensions are provided to make a quick and exact CAD drawing (F&D heads only)

This web page - Mar 8 2002

Elliptical Head - Version 2.11 - March 2002

Flanged and Dished Head - Version 2.13 - March 17 2002

Heispherical Head - Version 1.1 - Oct 24/2000 (2000 Code Version - not updated to 2001 code)

Toriconical Head - Version 1.1 - Oct 24/2000 (2000 Code Version - not updated to 2001 code)

Flanged and Dished (F&D) and Elliptical heads can be built according to UG-32 which specifies the forming dimensions, or by App-1-4 which allows the design to be customized within allowable limits. Both spreadsheets provides UG-32 dimensions as a starting point, and allows them to modified to meet the requirements of the design.

The F&D spreadsheet calculates the exact dimensions of the head. Drawing instructions for making an exact drawing are included, along with the critical dimensions. The F&D volume calculations have not been verified, but are close (within 2-3%) of the values in the "Pressure vessel handbook".

Consider Elliptical heads instead of F&D heads when: 1) the diameter is larger than 8ft. F&D heads are thicker than Elliptical and can be costlier. and 2) Elliptical heads with a larger Rf might not need to be heat treated.

You need to contact your head supplier for information regarding the amount that heads are reduced in thickness during forming. I use values of 1/16" for heads up to 1/2" thick, 3/32 for heads up to 7/8" thick and 1/8" for thicker heads for preliminary designs and quotations.

Run the appropriate allowed joint efficiency spreadsheet first to calculate the required value for E.

The calculated blank diameters for the heads are an aproximation. The weight of heads is an approximation based on the blank diameter and is only accurate for carbon steel.

See Appendix L for sample calculations.

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