Nozzle/Manhole Neck Materials

1) Yes it is to meet the code; and yes, you are allowed to use A106 Gr B piping OR rolled A516 plate. Just make sure you meet all requirements of UG-36, UG-37, UG-45.

2) Manholes and nozzles are both considered Openings as per the code and are to be designed. (They are essentially the same - except nozzles will generally have different loadings to consider under UG-45).

NOTES:

• As per UG-41 (if required) the strength of the material for reinforcing should be the same or greater than the shell - if not, a strength reduction factor has to be applied.
• If you are using pipe for the shell or nozzles you must include (decrease) thickness by the amount of mill tolerance.
  

Thinking a little more about your question (it's a little confusing) -

Is the vessel already designed with the materials to be used listed?

Are you asking if you can substitute A516 for A106-B piping during construction?

If so - I am going to give you the blanket answer of NO - you can not do that.

(if you are in the design stage - they can be easily substituted)

Dear Sir,

Due to unavailable stock for pipe above 20", we used plate instead of pipe. All calculation due this changes are passed. So its problem to change?

Thank you.

There is no problem as long as you take note:

• You have end-user approval (so that there are not any unforeseens such as corrosion problems due to the weld)
• The calculations have been performed and are documented
• The applicable NDT requirements have been met for joint efficiency in the design
• The Manufacturer's Data Report is properly filled out
  

Just to confirm a couple of things:

• Is this vessel designed to Division 1
• What is the thickness of this nozzle?
• What is the design/operating temperature?
  

Dear Sir,

Design According ASME Div.1

Thickness is 12.7t

Design pressure is 10barg with 60 degree design temperature

Is that 12.7 mm?

Also make sure you meet UCS-66 to be exempt from impact testing.

yup..

12.7mm thickness.

1> Your deviation is superior

2> Manhole is a Nozzle.

Careful!!! You can not blindly say that the deviation is superior - it depends on the design, welding, and NDT and you have to watch for Minimum Design Metal Temperature - it is possible, not likely, but possible - that the thickness of the rolled neck is much less than the thickness of the off-the-shelf pipe in which case according you have to use the ratio of required thickness to actual thickness in accordance with UCS-66 for impact testing and MDMT.

THE ENTIRE VESSEL MDMT MAY HAVE TO BE CHANGED.

DO NOT BLINDLY SAY IT IS SUPERIOR.

I have used SA 516 grade 70 instead of SA 106 B pipe many times for larger nozzles in both new design and alterations to older vessels. Having said this I do all the necessary ASME calculations for nozzle thickness, reinforcement etc and I review it with my Authorized Inspector and only proceed after his approval. I have never had a problem with doing this and it is fairly common thing to do in my area. All man-ways are considered openings and therefore nozzles according to ASME codes. With API 650/653 standards for atmospheric tanks a man-way is considered differently than a process nozzle and many times allowed to be made from lighter material. My advise is to proceed with your design after you have done the calculations and and had them reviewed by your A.I. and everything is proven to be acceptable by ASME code.

Interesting.

• There is not a word about the composition of the wetting fluid, nor its temperature and pressure.
• It is blindly assumed by the fabricator that the weld necessary to fabricate this thing from the flat has identical chemical resistance and mechanical strength to the <...seamless pipe...>.

Is this the right way to do business?

The original question(s) must be directed towards the Engineer/Surveyor from the company that is supplying burst/collapse insurance cover on the equipment, and not an anonymous on-line Engineering forum!