How to use the Tube sheet Design Conditions dialog?
In AutoPIPE Vessel, the table in this dialog indicates the design cases for the tube sheet. It is mainly use for the double fixed tube sheets heat exchanger to define the start up, shutdown and operating cases (for example see ASME VIII div. 1 UHX-13.4). For other types of heat exchanger like U tubes or floating head, this table must be filled with the Design Conditions of the heat exchanger. AutoPIPE Vessel fills automatically different cases using the design conditions of the heat exchanger.
For the double fixed tube sheets heat exchanger the inputted temperatures must be the mean metal temperatures used to calculate the expansion coefficient. The design temperature as inputted in the heat exchanger design conditions are used to determine the allowable stress of the tube sheet.
The software automatically define the test cases. It is not necessary to input them.
The Tags may be "N" or "X".
"N" is used to describe a "Normal case" (the allowable stresses are defined by the Design Pressure Code in normal conditions.
"X" is used to describe a "Special Case" (the allowable stresses are defined by a percentage of the Yield Strength 90% for example).