Hi all,

I have a question about modelling piping around a vertical in-line pump in combination with an API610 nozzle forces check.

Normally I would model a vertical inline pump that is not supported other than on the piping itself as a rigid with c-nodes on both sides and I would use the c-nodes for the API check.

Now I have a system with a vertical in-line pump which has supporting legs to support the pump itself on the floor. The manufacturer says they are made according to API610 and that the nozzle forces should be checked as such. Appendix F of API610 clearly states that it's about pumps that support on the piping only.

So 3 questions actually:
- is my original assuption correct for modelling inline pumps?
- can the supported inline pumps be checked according to API610?
- how should I model the pump and the piping in CII?
and as a seperate one:
- which cases (OPE, SUS, EXP etc) should be checked with API610? I can't seem to find anything about that. I assume it's OPE cases. Is this correct?

Thanks in advance for your reactions.

How big is this pump?
What does the pump weigh?
How big is the suction piping?
How big is the discharge piping?
What is the operating temperature?
What is the Flange rating of the suction and discharge piping?
How is the suction and discharge piping routed?
How is the suction and discharge piping supported?

Your pump can only be qualified against API 610 if it was designed and built to that Code.

Fig. 20 shows a supported in-line pump, and refers to Table 4 loads. Isthere any reason for not simply using these loads ?

You could model the pump as a rigid with appropriate weight. YOu may want to model the legs as pipe with equivalent stiffness to whatever the cross section is, and correctly model the leg / floor attachment.

If you are doing dynamics, remember to put in an element with the motor weight etc to properly distibute the mass.

The OPE case is the right one to use for pump nozzle loads, but you can improve the realism of the calculation by (assuming it's hot) running installation to max operating temperature and using the hot Young's modulus. Both should get the loads down.

Thanks for your replies.
@jop: the pump is fabricated according to API610 according to the manufacturer, so fits that rules. I think answers to your questions are not really relevant here for the supported/unsupported inline pump issue.

@MoverZ: I saw that figure, but appendix F says that for (and I can't literally quote cuase I don't have to code here atm) "inline pumps that are only supported on the surrounding piping the forces may be more than 2 times the table 4 values if.....".

So I got a bit confused because of this text and I want to know if this part of the code is used for supported inline pumps too.

Would like to hear some more comments.

The para from Appendix F limits principal stresses in the nozzles. As I said above, you don't have to use Appendix F to comply with API 610. Just comply withthe limit loads of Table 4.

Appendix F strictly does not refer to supported in-line pumps. However you could agree with the manufacturer to apply it. It would make sense to apply the App. F rules from horizontal pumps on the basis that verticals are less sensitive to nozzle loads.

Thanks for your reply. Problem is I need the app. F rules to get the nozzle forces to pass. Some forces/moments are too high according to table 4.
I'll try to contact the manufacturer.

Perhaps what you are thinking of is section 5.5.2 (2004 edition) about vertical in-line pumps, not Annex F.

SLH

Although you are exceeding Table 4 it's worth submitting your loads to the vendor for approval. Often it's only one force or moment that is ott and may be accepted.

@SLH: section 5.5.2. of API 610-10th edition (I use the ISO version ISO 13709 btw) says for inline pumps forces should be less than 2x table 4 values. That's also the check CII does.
If this isn't satisfactory Appendix F, part F.2. gives extra rules for the forces.
My nozzle forces are more than 2x table 4 values, so I have to use app. F.2 to check them.
I think I know enough atm. I've modelled the pumps as inline pumps with a flexible support (piece of small pipe), and checked the nozzle forces according to app. F.2 which makes them pass.
I'll give the forces to the manufacturer for a double-check.

Thanks all for your replies.