Calculations & Codes
At the core of DesignCalcs is an extensive set of calculations and the codes they reference. Each code adjustment results in a rigorous round of refactoring and testing to keep the software relevant and our users up-to-date.
ASME® Section VIII is but one of many codes referenced by DesignCalcs: other codes include ASME® Section II, B16.47, B16.5, B36.10M, in addition to multiple wind and seismic codes. The included codes allow DesignCalcs to offer you the most flexibility when designing vessels and components.
Calculations can be performed in accordance with the standard 3.5 to 1 or the alternate 4 to 1 safety factor, depending on your preference. DesignCalcs includes Minimum Design Metal Temperature (MDMT) calculations performed per UCS-66 that give a report summarizing the MDMT for all pressure components composed of UCS-23 materials. In addition, the software provides the ability to solve for the minimum thickness required to meet a given pressure or for the maximum internal pressure allowed for a given wall thickness.
Loadings and Attachments
DesignCalcs includes multiple options for calculating loadings and attachments. Get started by entering the load, magnitude, direction, and elevations. Save time by testing for multiple conditions with a single setup. The calculations take into account the bending and membrane stresses from attachments applied at different elevations. You may also choose to consider liquid, insulation, packing, and increased wind loadings; the presence or absence of these loadings during hydro testing may be specified as well.
The calculations for external pressure and minimum thickness are another feature of DesignCalcs. You no longer need to reference Figure G to determine Factor A or dig through the external pressure charts to determine Factor B: all of this information is already in the software and is applied automatically.
- Top Flange as Cantilever Beam
- Top Flange as aiding web for splitting stresses
- Bending stresses in base plate
- Base plate aiding web for splitting stresses
- Saddle splitting membrane and bending stress on web
- Combined bending and compression stress in the ribs
- Effective shell arc increased due to added rigidity of stiffening rings
- Stiffening rings checked for stresses from the saddle reactions
- Bearing stresses from base plate
- Seismic shear force
- Resultant forces
- Overturning moments
Base Plate Calculations
- Base ring only
- Base ring with gussets only
- Base ring with centered anchor bolt
- Base ring with gussets and continuous compression ring
- Base ring with gussets and compression plate (anchor bolt chair)
- Conical (minor opening on top & major opening at base) and Cylindrical
- Both Conical and Cylindrical can be designed in multiple sections of different geometries and materials
Leg & Lug Calculations
- Combined bending & compressive stresses
- Lug reaction
- Gusset reaction
- Moments about base plate
- Maximum/allowable weld stresses
- Induces shell stress
- Shell buckling stress
Wind and Seismic
The shape, size, and location of your vessel will determine what stresses must be considered. DesignCalcs offers the ability to easily calculate Wind and Seismic factors with reference to multiple codes. To encourage the safest design possible, the software uses the worst case directions for each considered elevation. Calculations include seismic shear with resultant forces and overturning moments between the elevations under consideration. First Natural Period of Vibration (FNPV) calculations are based on Rayleigh's un-dampened beam method utilizing superposition. Depending on your situation, force may also be calculated and evaluated separately or in various combinations.
Wind & Seismic Codes
- ANSI/ASCE 7-88
- ASCE 7-93
- ASCE 7-95
- ASCE 7-98
- ASCE 7-02
- ASCE 7-05
- ASCE 7-10
- UBC 1991
- UBC 1994
- UBC 2997
- IBC 2000
- IBC 2003
- IBC 2006
- IBC 2009
- IBC 2012
- CBC 2010
Cone to Cylinder
The DesignCalcs Cone to Cylinder analysis allows for optional consideration of the cone to cylinder juncture within a pressure vessel per ASME Section VIII, Division 1, Appendix 1-5 and Appendix 1-6. Internal pressure discontinuity checks and external pressure discontinuity checks with line of support calculations are examined. Pre-designed shells and cones created within DesignCalcs can be seamlessly imported, reducing redundant data entry and the risk of errors while providing a cleaner and faster workflow.
The cone to cylinder analysis provides enhanced flexibility by allowing for adjustments to longitudinal efficiency, section length, pressure, and static head independent of the component elements themselves. Axial loads in compression or tension can be applied at the cone to cylinder junction. In addition, the analysis can take advantage of rings in the discontinuity check.
WRC-107 calculates combined stresses at the junction of an attachment and a shell, head, or other similar host. Calculations may be used for structural supports, reinforcing pads, clips, or any structure attached to the cylinder or head that has loads applied to it, as well as nozzles and nozzle reinforcing pads subject to various loadings.
- Hollow & rigid cylinders
- Hollow & rigid squares
- Radial load
- Negative radial load
- Longitudinal moment
- Circumferential moment
Combined Stress Options
- Minimum of Cs*S and Cy*Y
- Maximum of Cs*S and Cy*Y
- Collective or separate
- External shear (circumferential or longitudinal)
- External overturning (circumferential or longitudinal)
- External torsional/twisting