API 937 : 1996

1.0 Introduction
2.0 Background Information
      2.1 Description of Typical Tank Design
      2.2 API 650 Design Rules for Frangible Roofs
      2.3 Derivation of API 650 Rules
      2.4 Derivation of Wc and Wh in API 650 Design
           Rules
           2.4.1 Derivation of Wc
           2.4.2 Derivation of Wh
      2.5 Summary of Frangible Joint Study by British
           Researchers
3.0 Combustion Analysis
      3.1 Combustion Wave Geometry
      3.2 Combustion Calculation
           3.2.1 Flame Temperature Calculation
           3.2.2 Burning Velocity
           3.2.3 Calculation of Pressure Rise
      3.3 Venting
      3.4 Pressure Sensitivity Study
           3.4.1 Effect of Ignition Source Location
           3.4.2 Effect of Tank Size on Pressure Rise
           3.4.3 Effect of Different Fuels and Air-to-
                  Fuel Ratios
4.0 Structural Analysis
      4.1 Scoping Analyses of Full Scale Tanks
           4.1.1 Static Stresses at the Roof-to-Shell
                  Joint
           4.1.2 Axisymmetric Modal Analysis
           4.1.3 Elastic Buckling Analysis
      4.2 Analyses of Model Tanks Tested Dynamically
           4.2.1 Axisymmetric Large Displacement
                  Static Analysis
           4.2.2 Axisymmetric Large Displacement
                  Dynamic Analysis
           4.2.3 3-D Large Displacement Analysis
           4.2.4 Analysis of Stitch Welded Tank
      4.3 Analyses of Small Model Tanks
5.0 Testing
      5.1 Joint Details
      5.2 Static Test of Small Scale Model Tanks
      5.3 Dynamic Test of Model Tanks
           5.3.1 Objectives
           5.3.2 Design of Model Tanks
           5.3.3 Test Description
           5.3.4 Results of Testing
6.0 API-Tank: A Program for the Design/Analysis of
      Tanks with Frangible Roof Joints
      6.1 Automatic Design
      6.2 Structural Analysis
      6.3 Nonlinear Solution Procedure
      6.4 Combustion Calculation Procedure
      6.5 Frangible Joint Failure
      6.6 Verification
7.0 Evaluation of Tanks
8.0 Conclusions
8.0 References
9.0 Acknowledgements
Appendix A: List of Ansys files for verification
      A.1 Input File for Example Tank 1
      A.2 Input File for Example Tank 2

Describes research that evaluates the ability of the present API 650 tank design criteria to ensure the desired frangible joint behavior. Particular questions include: (1) evaluation of the area inequality as a method to predict the buckling response of the compression ring, (2) effect of roof slope, tank diameter, and weld size on the frangible joint, and (3) effect of the relative strength of the roof-to-shell joint compared to the shell-to-bottom joint.