Tubesheet - Channel
(Fixed, Floating, and U-Tube)
Channel Information
Several of these fields will be automatically completed based on the host channel shell/ channel head information when the Channel Shell Search or Channel Head Search is used. The content of those fields will be locked.
Description: The label given for the component.
Channel Type: Select Channel Shell or Channel Head. At this time, only Hemispherical Channel Heads are available for use in tubesheets per ASME Section 8, Div 1, Part UHX.
Temperature: The maximum mean metal design temperature for the internal pressure case as defined in UG-20(a).
Corrosion Allowance: Corrosion allowance on the inside of the component (concave side).
Inside Diameter: The component diameter in the new condition.
Thickness: This value is in the new condition. For the component to pass, this value must be at least the sum of the thickness necessary for pressure and temperature, corrosion allowances, and forming allowances or under-tolerances. If the thickness necessary for pressure and temperature is less than the thickness required by UG-16, the nominal thickness must be at least the sum of the UG-16 thickness and the tolerances, etc. In some cases, under-tolerance is not considered (e.g., for nozzle reinforcement, the under-tolerance of the nozzle neck is ignored). When “Solve for Thickness” is selected, the software will determine the smallest standard size that passes. The user is able to manually edit this value.
Liquid Density: Refers to the shell side liquid. This is for information only.
Per UG-23(e), calculate using: Select whether to calculate the allowable primary plus secondary stress using 3xS or 2xSy. Caution: If 3xS is selected and the value of S is determined at 90% of Sy, the allowable primary plus secondary stress will be 2.7xSy.
Channel Material
Material: A brief description of the component material. When the material selection dialog is used, the default description is based on settings on the Materials-Misc. tab under Tools > Defaults. For example, if the settings are for Spec and Type/Grade and the material is SA-516 Grade 70, this field will show SA-516 Gr. 70. If the settings are instead just for Spec, the field will show SA-516. The field may be edited by the user to say anything without breaking the relationship to the material database; while this flexibility can be very helpful, the user must take care to enter correct information.
Condition: A brief description of the component material. Similar to the "Material" field, the description will default a certain way based on settings on the Materials-Misc. tab under Tools > Defaults when the material selection is used. This field may be edited by the user without breaking the relationship to the material database. As with the “Material” field, the user must take care to enter correct information.
Density: The material density based on table PRD from Section II, Part D. For those materials that did not have a clear match in this table, every effort was made to assign conservative values. Manually editing this field will sever the connection to the material in the database as indicated by the "Unlisted Material" caption.
B-Table: The external pressure table assigned to the material in the allowable stress tables in Section II, Part D. The table is used to determine the external pressure strength of the component and also the longitudinal compressive strength. Selecting a Factor B table other than the one assigned to the material will sever the connection to the material in the database as indicated by the “Unlisted Material” caption.
Poisson: Poisson's ratio for the selected material.
(Tc'): The metal temperature of the channel at the tubesheet as expected during operation. It is generally not conservative to substitute the channel design temperature for Tc'. This value is only required for radial differential thermal expansion calculations.
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