Allowable Stress in ASME VIII, B31.3, API 650, API 653

Basis of Allowable (Design) Stress in ASME VIII Pressure Vessel and ASME I Boiler; 

(The Allowable Stress from SMTS and Allowable Stress) as well as the ASME B31.3 Proces Piping, for ASME VIII Pressure Vessel and ASME I Boiler values Allowable Tensile Stress of Material , the Code permits used to calculate the thickness and composition.

The variables that are used to handle the pressure of the Pressure Vessel and Boiler will be specified in the ASME BPVC Section II Part D, which is generally equal to A value that is less than 1/3.5 Tensile Strength and 2/3 Yield Strength of that material. For the same reason is to be Safety Factor ensures that the material will not deform or damage when used under the pressure designed.

Allowable stress ASME VIII.png

Basis of Allowable (Design) Stress in ASME B31.3 Process Pipping; 

For Process Piping Design according to ASME B31.3 Code is set to take the Allowable Tensile Stress of Material to calculate the thickness and composition. Of the pipe that is used to pressure by the Allowable Stress that Code allows in the calculation is generally equal to A value that is less than between 1/3 Tensile Strength and 2/3 Yield Strength of that material. This is to be a safety factor to ensure that the material will not deform or damage when used under the pressure designed.

Allowable stress ASME B31.3.png

Basis of Allowable (Design) Stress in API 650 Storage Tank and API 653; 

Atmospheric Aboveground Storage Tank designed according to API 650, the Allowable Tensile Stress of each material that Code allows to calculate the thickness and Shell, which receives the pressure from the weight of the liquid. In general, it is equal to A value that is less than between 2/5 Tensile Strength and 2/3 Yield Strength of that material to be a safety factor. Ensure that the material will not deform or be damaged when used under-designed pressure.

Storage tank API 650 courses.png

But if the Storage Tank is in use (In-Service) according to API 653, it is allowed to use Allowable Tensile Stress which is higher than when Design in calculating Minimum Serviceable Thickness or Minimum Required Thickness of Storage Tank Shell. Over the 0.429 Tensile Strength and 0.8 Yield Strength for 1st and 2nd Shell, Courses, and the lesser between 0.472 Tensile Strength and 0.88 Yield Strength of materials for 3rd Shell Courses and upper.

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Allowable stress API 653.png

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