Head/Conical Reducer - MDMT/Misc

Last Updated 2019.8

(Includes Jacket and Heat Exchanger Components)

Other Calculations

Perform UCS-66 calculations: Selecting this check box will cause the software to perform UCS-66 toughness calculations on the component. This option is only available to materials that are classified as UCS materials per Table UCS-23.

Exemption Drop-down: When UCS-66 calculations will not be performed (the software will not allow these calculations when a non-UCS material is used), an exemption must be entered. The exemption may be typed in or selected from the drop-down options, but the user is responsible for ensuring that the exemption selected is valid for the material, service, etc., in question.

Ignore Appendix 1-4 Strength Penalty check box: Selecting this check box will ignore the requirement for penalizing the maximum allowable working stress as stated in the 1-4 nomenclature. 

MDMT Reductions

Take UCS-66(b) Reduction: Selecting this check box will take advantage of the reduction in allowed MDMT per UCS-66(b). This paragraph includes a calculation for the component which compensates for any excess material thickness in the component.

Apply UCS-68(c): Selecting this check box will give an additional flat reduction in the allowed MDMT per UCS-68(c). Carefully review this paragraph as there are steep requirements for this exemption.

MDMT

MDMT Pressure: The net internal pressure (concave side) on the component coincident with the minimum design metal temperature (MDMT). This includes static head.

MDMT Curve: The notes in Figure UCS-66 provide the criteria to assign the MDMT curve to the material and product form of the component. Curve A will give the least favorable allowed MDMT and Curve D will give the most favorable allowed MDMT. When UCS materials do not have a clear match using the criteria, they are assigned a conservative value of A. As the software cannot currently obtain possible improvements in curve rating due to heat treatment and other factors, the user may override the curve value.