Header calculation according to ASME Section I

[FabianoRibeiro]

Dear all,

In paragraph PG-27.2.2 of ASME Section I (2007), the code indicates the formulae for calculation of thickness and pressure of cylindrical components under internal pressure. In the formulae, the efficiency E is described as:

1,00 for seamless or welded cylinders; or
efficiency from PG-52 or PG-53 for ligaments between openings.

In the case of a manifold of a coil with holes along a diagonal, the efficiency used for the calculation of this manifold would be the one calculated according to PG-52.4. Is this correct?

Thanks.

 

[metengr]

In the case of a manifold of a coil with holes along a diagonal, the efficiency used for the calculation of this manifold would be the one calculated according to PG-52.4. Is this correct?

Yes.

 

[FabianoRibeiro]

Thank you, metengr.

Do you have any advice on how should I consider the loads due to the coil tubes (weight, for instance)? Is there any paragraph in ASME or any other code, such as API, that adresses these loads?

Best regards.

 

[metengr]

FabianoRibeiro;
Yes, but in general terms (see PG-22).The ASME B&PV Code is a design by rule for Section I service. This means that primary membrane (allowable) stress is used for design and other stresses (secondary and bending) are such that they fall well below the primary membrane stress. In simple terms with the design by rule equations provided by Section I, other stresses are not significant because of the 3.5 design margin.

As a good design engineer you should still evaluate the secondary and bending stresses to determine their magnitude in comparison to the primary membrane stress from pressure.

 

[FabianoRibeiro]

Thanks again,

I couldn't find procedures for MDMT calculation and formed heads with pressure on convex side. Are there such procedures in Section I or should I use the ones described in section VIII?

Best regards,