B16.5, Section VIII, and dual cert. SS

[BigTank]

Consider a flange, SA-182 F304 150# class, having a rating at 1000°F of 20PSI. Now what arrives at your shop is certified as SA-182 F304/304L.

If my dual grade philosophy is to consistently use the stress values for the straight grade material when considering pipe and plate, am I justified in using the RATING for the SA-182 F304 flange material in keeping with this philosophy?

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Fitter, happier, more productive

 

[TGS4]

Yes.

 

[BigTank]

Nice. Thank you. I just wanted to be sure that, in this case where the part is rated for pressure at temp vs. designed for thickness based on allowable stress, my philosophy was consistent with the Code.

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Fitter, happier, more productive

 

[SnTMan]

Also specifically permitted by B16.5, see 2.9.

Regards,

Mike

 

[jte]

Multiple Material Grades
Material for flanges and flanged fittings may meet the requirements of more than one specification or the requirements of more than one grade of a specification listed in Table 1A. In either case, the pressure–temperature ratings for any of these specifications or grades may be used provided the material is marked in accordance with para. 4.2.8.

Dual certified is just that. Its your choice which material certification you wish to consider - but for Code purposes you have to choose one and stick with it. For example, you can't list a flange on Code paperwork as dual certified and use a "straight" grade rating for pressure and "L" grade for welding procedure.

See also II-D Appendix 7.

jt