Inputs required for performing WRC checking:
The following documents must be ready with you before you start to perform WRC 107/297 checking:
1. Equipment Details/ General Arrangement Drawing
2. Nozzle details
3. Line list

Step by Step methods for performing WRC 107/ WRC 297 calculation in Caesar II:

Step 1: Perform Static analysis of the stress system and find out the nozzle loads required for checking local stresses.
Step 2: Enter into the WRC module from Caesar II. Provide a file name for your job

Step 3: Following screen will appear. Enter the Nozzle data as mentioned below:

Step 4: Now enter the vessel details i.e, diameter, wall thickness, corrosion allowance and material.

Step 5: Input vessel and Nozzle direction cosines, Internal design pressure and load and moments values from Caesar static analysis output (Sustained, Expansion and occasional as applicable).

Step 6: On options it is suggested not to change any parameter. Now click on analysis to read the results. The output will inform you whether WRC checking is passing or failing. Use results as per your requirement.

For entering loads and moments as per local convention following description and figure can be used for converting global forces into local forces:

As shown in fig, Stretch your right hand with Middle finger along the Vessel Centerline. Index Finger should parallel to nozzle centerline and should point in a direction from nozzle towards entering vessel. And Thumb should be perpendicular to both. Then1.Direction of Index Finger represents +P.
2.Direction of Middle Finger represents +VL
3.Direction of Thumb represents +VC
4.ML will be positive if by applying right hand thumb rule to ML, direction of thumb is same as that of VC.
5. MC will be positive if by applying right hand thumb rule to MC, direction of thumb is opposite to direction of VL.
6.MT will be positive if by applying right hand thumb rule to MT, direction of thumb is opposite to direction of P. Get the loads and moments from CAESAR output. Compare the direction of Forces and Moments in CAESAR output with conventional Force and Moment directions and enter the values of P, VL, VC, MT, MC and ML accordingly.

STORAGE TANK PIPING STRESS ANALYSIS AS PER API 650 USING CAESAR II:

Tanks are one of the most important equipment for storing large amount of fluids which might be highly toxic, flammable or injurious to environment and failure at any point could result into highly hazardous or fatal accident. So proper analysis of tank connected piping system is required for accurate functioning and safety. I will give emphasis on modeling of tank, load cases for tank piping analysis in Caesar II, tank nozzle load checking as per API-650.

Documents required for Stress Analysis:

1- Tank G.A. drawing indicating nozzle elevation, nozzle projection.
2- Allowable load for tank nozzle as per vendor/manufacturer, if available.
3- Piping isometric, Line list, P&ID etc.
4- Soil settlement data of that region as per civil department.

Modelling Procedure in Caesar II:

1- Model the nozzle flange (10-20) as per tank flange pressure rating.
2- Model the projection as pipe element (20-30) with same pipe diameter & schedule given in the drawing for the nozzle up to pipe and tank intersection.
3- For tanks having diameter less than 36 meter model 40-50 and 50-60 in the same way as followed for normal pressure vessels. Provide anchor at node 60 with CNODE at 61. Add the settlement displacement if any at node 61.

1- Following steps to be taken when doing the stress analysis for the lines connected to tank having diameter more than 36 meter:

2- Engineering/Process data sheet to be obtained from Process team to evaluate parameter (Radial Growth, unrestrained rotation, allowable forces and moments) as per API 650 as shown in the following figure: