Generally, elliptical dished heads

• are manufactured on 2:1 ratio of major to minor axis and is recommended to be used for pressure vessels operating above a pressure of 1.5 MN/m2 .
• resist half the pressure rating compared to hemi spherical head provided on the cylindrical shell of the same thickness and diameter.
• are approximately as strong as seamless cylindrical shell having the corresponding I.D and O.D.
• all (a), (b) and (c)