Nozzle Openings in existing Manway

[auba]

Dear Freinds,

Do ASME SEC VIII recommends any openings in manway closing door/plate.

I want to permanently close one existing manway and want to introduce two nozzle openings in its closing door.

Are these openings recommended in SEC VIII.

Any comments form your experience will be appreciated.

Thanks

 

[unclesyd]

We have done this many times. You still have to do the calculations to see if the cover plate is thick enough.
Be careful to insure that the piping doesn't apply any additional loads on the cover plate that would affect the integrity of the seal.

It is a routine feature to use the nozzle for an inserted heater to be the manway.

 

[auba]

Hi friend,

i understood..... but i just want to know what asme cesc viii says on this situation....

moreover nozzle loads can be checked easily....using pvelite or any other software....

but...as you qouted....

Be careful to insure that the piping doesn't apply any additional loads on the cover plate that would affect the integrity of the seal. <======= how can i check this. i mean how i can check manhole plate will no vibrate enogh or get so much loads that it would break up..

Thanks

 

[unclesyd]

Your software should let you apply an external load to any nozzle though it might take a little extra calculations to transfer the loads from the new nozzles to cover plate. I don't recall that we were able to do this satisfactorily. Again if I recall we insured that we had enough excess plate thickness and bolting to more than cover the gasket seating stress of the manway cover.
A good flexibility analysis of the new piping will help keep external forces off the new nozzles and cover plate. On all our bayonet steam heaters we designed to keep any any external, especially those imposed by thermal, forces of the nozzles on the cover plate.

Any flow or transferred vibration in the connecting pipe will have to dealt with separately.

My old code books cover nozzles in flat cover plates in UC-39 with references to Appendix II. If this isn't current some will you the current applicable references. Note that the nozzle area is a critical variable. If you fall out of dimensionally you might have to look the tube sheet section.

Comeback with some relative dimensions if possible.

 

[mafa]

Hi auba,

I am in the same situation. There is actually another forum here that is handling the same information (UG-39 in the title). Check UG-39 for the cross-sectional area you need when you open a hole on a blind flange, which is considered a flat head in this case.
Apparently it is something you can do.... but in my case, i don´t want to use the manhole because it leaves the next two manholes 15 meters (49 feet) apart, and this is too much distance from the inspection point of view... Consider that when you decide to disabel a manhole.