Choose flanged only non-code type tank heads for tanks that are not under pressure. These heads can be formed from carbon steel, stainless steel, aluminum, and other ferrous and non-ferrous metals and alloys.
Inside Knuckle Radius: ASME requires a minimum of 3 X the material thickness, but depending on the diameter and thickness, a larger IKR may be required.
Typical Thin Out Allowance: 1/2” and Under – Add .03125” to the minimum. Over 1/2” – Add .0625” to the minimum.