Enter the crown radius for torispherical heads. The crown radius for a torispherical head is referred to as the dimension "L", in the ASME VIII Div. 1 Code.
This dimension is usually referred to as "DR" in many head catalogs. Even though the head catalogs list these heads as being "OD" heads, the crown radius is given on the inside diameter basis. See the illustration in the catalog and where the arrows for "DR" and "IKR" point to (the inside of the head). For more information, see Appendix 1-4 in the Code.