API 650 Determine Product Design Stress, Sd, of other materials than Table 5.2a

[takiyasamsama]

Hi all,

Is there any specific formula or method to determine Product Design Stress, Sd, for other materials besides that mentioned in Table 5.2a for metric unit. If there is any table or reference for this it would be so much helpful.

Thank you in advance

 

[IFRs]

Materials not listed might be used, but you can't say the tank is per API 650. That being said this may help you:

5.6.2.1 The maximum allowable product design stress, Sd, shall be as shown in Table 5.2a and Table 5.2b. The corroded plate thicknesses shall be used in the calculation. The design stress basis, Sd, shall be either two-thirds the yield strength or two-fifths the tensile strength, whichever is less.

5.6.2.2 The maximum allowable hydrostatic test stress, St, shall be as shown in Table 5.2a and Table 5.2b. The nominal plate thicknesses shall be used in the calculation. The hydrostatic test basis shall be either three-fourths the yield strength or three-sevenths the tensile strength, whichever is less.

 

[takiyasamsama]

IFRs,

Thank you for highlighting that up to me. I missed out on that clause.

However for material not listed in API 650 is considered to be non-API 650 tanks, in what clause is that being mentioned in the standard? Is it 4.1.2?

Thank you.

 

[fegenbush]

takiyasamsama,

Yes, 4.1.2 of API 650 permits the use of materials not covered in the standard, *if* the material can be shown to meet *all* the requirements of a material listed in the standard. If your material does not meet *all* the requirements of a listed material, it may not be used.