How are loads from attached external piping considered in ASME VIII-2?

[HPVDE]

I was wondering if anyone here could shed some light on where the loads resulting from attached external piping are covered in the design loads and load combinations in Tables 4.1.1 and 4.1.2 of ASME Section VIII, Division 2.

The European code EN 13445-3 explicitly addresses loads from attached piping in its paragraph 22.4.6. I cannot find any explicit mention of piping loads (other than their weight) in tables 4.1.1 or 5.2.

In the same context, are loads due to bursting of rupture discs considered "Live loads"?

 

[IdanPV]

Table 5.1 contain "piping loads" as loads and load cases to be considered in a design.

 

[HPVDE]

Yes, thank you. I noticed that. But the question is, under which design load parameter are they covered in table 5.2 (T?) or 4.1.1?
Table 5.1 simply states that they must be considered in the design. I'm trying to understand which load combination takes into account external nozzle loads plus seismic, wind, etc.

 

[Snickster]

The attached is from Pressure Vessel Design Handbook, 2nd edition, H. Bednar, which discusses local loads on vessels in detail for Div 1 & 2.

 

[Trestala]

In the same context, are loads due to bursting of rupture discs considered "Live loads"?

Bursting rupture discs are not Live Loads. Live Loads are due to occupancy (people, vehicles, equipment, etc. on platforms for example).
They could probably be more of a dynamic/impact loading.

Yes, thank you. I noticed that. But the question is, under which design load parameter are they covered in table 5.2 (T?) or 4.1.1?

The piping loads themselves can be "divided" into separate parameters. You have superimposed and sustained dead loads of the weight of piping that would be transferred down to the foundation, thermal loads that may or may not be transferred to the equipment, occasional loads from wind/seismic on the piping that are transferred (or not) to your equipment. All of those would vary depending on the arrangement of your piping and how it is supported.

 

[Snickster]

I agree with trestala. A rupture disc reaction force would be considered a local mechanical impact load on the nozzle. Whatever theoretical force that is determined it should be multiplied by 2 for maximum impact factor.

 

[HPVDE]

Thank you all for your responses.

I had already considered a DLF of 2.0 for the burst disc load.

I have the book by Bednar and will have a look there. Thank you anyway for sharing it.

I know that I can evaluate additional load combinations to ensure that the design is sound, I just wanted to make sure that I was adhering to the load combinations defined in the code first.

 

[TGS4]

Piping loads should be considered as D loads in Tables 4.1.2 or 5.3 (or even 5.4 or 5.5). Do NOT consider the restrained free thermal expansion loads of the piping as T loads in these Tables. This is clarified in Table 5.6. And it’s been covered in numerous ASME PVP papers.

Burst disc loads would not be L - live loads. With the appropriate DLF, treat it as D.

 

[HPVDE]

Piping loads should be considered as D loads in Tables 4.1.2 or 5.3 (or even 5.4 or 5.5). Do NOT consider the restrained free thermal expansion loads of the piping as T loads in these Tables. This is clarified in Table 5.6. And it’s been covered in numerous ASME PVP papers.

Burst disc loads would not be L - live loads. With the appropriate DLF, treat it as D.

Thank you all for your help.

A few years ago a PE specifically requested that we include the load from RD bursting under live loads, to avoid further discussion and knowing that it didn't belong there, we did so.

Whilst I can understand the reasoning behind considering these loads under D, dead loads, this is not what the code implies in its description of D in tables 4.1.1 or 5.2.

The European Code seems to deal with this in a much clearer way, without requiring designers and third parties checking their work to refer to external research or interpret more than is absolutely necessary.