The formula for the typical 2:1 elliptical head is listed in paragraph UG-32(d) of ASME Code Section VIII, Division 1. The general formula for all elliptical heads within the dimensional scope is addressed in Appendix 1-4. Factor K varies depending on the shape of the ellipse. Please note that an elliptical 2:1 head must not be mixed up with the German DIN 28013 torispherical head (Korbbogenboden). Although both types of heads are within each other’s shape tolerances, they shall be calculated using different formulas resulting in different required thicknesses. As a rule the required wall thickness of an elliptical 2:1 head is less than that of a Korbbogenboden. If a nozzle reinforcement calculation in the crown area is needed, however, the Korbbogenboden formula is more advantageous.
| P |
= |
MAWP + hydrostatic head
at operating conditions |
| Do/D |
= |
ouside/inside diameter of
the straight flange in corroded condition |
| S |
= |
allowable stress value
from Section II, Part D of the material at design
temperature |
| E |
= |
efficiency factor 1 for
seamless heads if UW-11(a)(5)(b) is met (Cat. B o C
adjacent butt welds needs to be spot radiographed
as a minimum) otherwiese 0,85. |
| h |
= |
inside height of the head
without straight flange in corroded condition
(example: typical 2:1 elliptical head with 1000 mm
inside diameter => h = 250 mm) |
If you have further questions please contact us directly or start a discussion in our
ASME Code Forum. To stay informed about any changes and amendments to our websites, upcoming seminars and the latest information about the ASME Code, please feel free to subscribe our newsletter.
These calculation tools are intended to be used
for information and guidance only, they do not
replace a detailed design calculation and
compliance with all applicable Code requirements.
CIS GmbH expressly disclaims liability for errors
and omissions in the contents of this site.
ASME Code Wochen
DE
NL
BE
FR
