Recommended Nozzle Loads 5

[j13m]

A question that has probably been asked several times but I was unable to find a straight answer - Where is a good place to find recommended nozzle loads (forces and moments) for process equipment for use in a WRC-107 analysis?

 

[fegenbush]

The best place to obtain this information is from the pipe stress analysis. If that information is not available, contract requirements are the next best source.

 

[gr2vessels]

A very broad accepted figure is forces F = +/- 40 x DN and moments are M = +/- 60 x DN. It is a conservative approximation, but is not intended for design use as it is not considering specific process rating or even piping rating.
However, fegenbush advice is safer, to get the piping stresses from piping stress analysis.

 

[SnTMan]

Recommended is NONE. Vessels are not to serve as piping anchors

Regards,

Mike

 

[XL83NL]

You might find some ASME PVP Conference Proceeding papers interesting. One I could recommend; PVP2013-97532.
Take a look at ASME's DC website for more potential papers.

 

[C2it]

So what are we looking for ?

Really it's a set of forces and moments for a given nozzle that are realistic and which may be used with confidence by both the equipment designer and the piping stress engineer, whilst doing their work in parallel. Conventionally an accepted set of data is used as a max by the piper and min by the equipment designer.
It is not usually feasible to complete a vessel design prior to starting a piping stress analysis or vice versa.

To suggest zero allowable equipment loads means .... don't connect any pipe to it, perhaps park it in a field.

There are perfectly reasonable sources of allowable nozzle load sets such as NEMA SM-23, API 610, API 650, API 661 etc. The only grey area is vessel and exchanger nozzle loads. These are addressed in an easily usable form in NORSOK R-001 section 5.1.5, available on the web, free of charge.

 

[gr2vessels]

Star for you, competent engineer!

 

[jtseng123]

Many engineering companies as well as oil companies have set a preliminary nozzle loads (forces and moments) for each nozzle size for vessel fabricators to qualify the nozzles and to ensure sufficient reinforcement is provided, and also for pipe stress engineers to limit their nozzle loads within that range to make sure proper pipe support is provided so not to cause redesign of the nozzle. This topic has been discussed in the past.

 

[MJCronin]

This has been discussed before...

http://www.eng-tips.com/viewthread.cfm?qid=287893

Cranky older engineer response (caution..!!)

http://www.eng-tips.com/viewthread.cfm?qid=217228

MJCronin
Sr. Process Engineer

 

[JStephen]

I believe the reference above to API-650 is in error, don't know about the others. So far as I know, API-650 doesn't give allowable nozzle loads in the sense that is being asked. For a specific tank size and wall thickness, it will indicate the combinations of axial load/moment that are acceptable- essentially a simplified version of WRC 107 for tanks. But there's nothing like a requirement that a Size X nozzle be adequate for Y foot-lbs.