SOME QUESTIONS ABOUT ASME VIII

[mgiani84]

Hi, I´m still working with the design of a vessel using ASME VIII.
I have four questions about some information of the code.

1-In what part can I find the maximum allowable loads in nozzles? (I mean the axial load and circunferential and longitudinal moments)

2-What about heat treatment? (for example, what kind of documents I have to ask to the manufacturer?)

3-Requirements for lift lugs. Method of calculations of these parts.

4- And the last one, Requirement for bold material. With that, I mean the way I have to take to select a bolt material

I´m using division 1, but if I have to change I´ve time to do this. the internal pressure of the vessel is 30 PSI

Thanks a lot.

Regards

 

[vesselfab]

30 psig should yield a thin wall vessel to Div. 1.

PWHT should not be required by code under most circumstances unless a special process service requires it.

Allowable loads for nozzles, now that's a sore point for me as a manufacturer. There is an infinite number of possibities for loadings on nozzles. The engineer should give the manufacture loads that will be imposed by piping and manufacturer can design to withstand those loads.

Do not know what material you have selected, but for the majority of P-1 materials, you will use A-193-B7 Studs w/ A-194-2H heavy hex nuts for bolting

 

[metengr]

mgiani84;
I reviewed your post and the questions you are asking pertain to the responsibility of the design engineer, and are not found in the Code. In other words, if you are the designer, you must be familar with alloy selection based on environment, bolt selection is based on your specific design requirements, PWHT requirements are base don both Code rules and your process specific requirements.

What I trying to say is this "seek professional engineering help" from an experienced pressure vessel design engineering company. You can work together and learn from them.

 

[littlechickend]

hi,

- loads imposed to nozzle shall be taken from piping engineer with piping stress analysis sofware or from supplier if it is mounted with machinery such as agitator. and then you have to perform strength calculation for this nozzle with allowable stress based on nozzle material by software or by hand.

- PWHT should read UCS 56, 79 for carbon steel. Document shall be submitted from vendor is PWHT procedure for checking if your equipment require PWHT (fluid inside)

- lifting lug cal. can refer to Dennis R. Moss Pressure Vessel Handbook or by PVElite programe.

- normally is A-193-B7 Studs w/ A-194-2H heavy hex nuts for flange bolting and A36 for anchor bolt.

 

[vesselfab]

littlechickend,
the vendor should only determine if PWHT is required for mechanical reasons cover by the applicable code and furnised specifications, ie low temp, thicknes, etc.
process/mechanical engineer for user should determine if PWHT is required for process reasons.
The equipmen vendor should not be expected to know the fluids inside and the process.

this is coming from a manufacturer's point of view.

 

[littlechickend]

Yes, you right. I just tell him that the equipment is required PWHT by process reasons (on data sheet)specified by Contractor or by applicable code, the document shall be submitted just for checking PWHT procedure. It is done by vendor.