2500# pressure rating large pipes 2

[Sawsan311]

Dear All,

For large pipe sizes above 24'' with a flange ANSI rating 2500# , ASME code may not cover standard pipe sizes for the same. However, is there any market limitation in manufacturing custom pipes with sizes as high as 40' , 42'' , 36'' etc for a ANSI rating of 2500#?

Thanks

Regards,

 

[LittleInch]

Sawsan.

First, there is no such thing as ANSI #2500. There is ASME B 16.5 flanges class 2500. If yo spend a little time getting the terminology correct, things might get better for you.

Similarly "ASME code" means nothing. ASME publish hundreds of codes - which one in particular were you referring to?

But no, there is no reason why you can't manufacture anything you want, but you are basically making a long thin pressure vessel here with the thicknesses you will need.

Really thickwall vessels / pipes are calculated and designed differently to thinner pipes.

I think these would be a "special" and priced accordingly.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Sawsan311]

Dear LittleInch, it seems you did not understand my query or did not get the actual limitation of availability of 2500# thick pipes for sizes larger than 24''. In fact, as per ASME B36.1, maximum thickness for standard 80'' pipe is 31 mm. For 2500#, calculated thickness would be in an order of magnitude of more than 80 mm, this is outside the scope of ASME B31.3.
Obviously I was referring to ASME B31.3 since I was referring to piping system.

I can understand that you are implying that very high pressure pipes will have to be manufactured as high pressure thin vessels in accordance with ASME SEC VIII.

 

[csk62]

I think @littleinch was referring to Section VIII Division 3 and B31.3 Chapter IX which are for high pressure/thick wall pressure systems generally beyond 2500# class. The wall thickness equations, assumed failure mode, NDE etc are quite different in chapter IX than base b31.3 code.


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Not making a decision is a decision in itself

 

[MJCronin]

LittleInch and csk62 give good solid advice ....

If anyone does not understand or confuses the definition of terms, then we cannot understand what you are trying to do and we cannot help you.

Do you have a specific project and need to know specifics about large diameter, high pressure systems ?...... or, as seems more likely, are your questions based on random thoughts and an excess of spare time ... ???

Lets start simple:

1) What is the MAWP of your piping system ?
2) What is your desired material ?... Carbon Steel ?
3) What is your required pipe diameter based on YOUR flow requirements ?

MJCronin
Sr. Process Engineer

 

[LittleInch]

You forgot how much money do you have to spend??

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[georgeverghese]

We had similar problems with getting custom made 36inch flanges in 1500lb service made out of 22Cr duplex many years ago - the mechanical engineer responsible for this was a hair's breadth away from a public lynching several months later for some errors which resulted in having to re order these flanges.

 

[Sawsan311]

Dear All,

Thanks for your feedback, I think respect is very important in our communications and when we reply to each other. The questions posted here are not random and don't come from excess spare time. If you assume that all Chemical Engineers memorize the chapters in ASME code like a piping Engineer, then you need to revisit that the answer to this assumption is NO.

The query was very simple with regards to availability of large diameter > 24'' pipes (48'', 52'') with a design pressure of 320 barg and hence 2500#.

Mr. LittleInch, this is a technical system requirement which is not only driven by the ''money'' you are referring to.

Regards,

 

[LittleInch]

Sawsan311,

The issue here is that if you had put into your original post the information in the second then it would have looked more like a "proper" question and not one which looks like a very flippant enquiry.

it is always much better to give some sort of background as to why you're asking the question and some idea of what you've already looked at.

BTW is it ASME B 36.10 you refer to? This simply lists standardised sizing commonly used. It doesn't limit pipe thickness above or below that range, but it does indicate you're into "special" pipe.

"Obviously I was referring to ASME B31.3 since I was referring to piping system." Well no it wasn't obvious and it could be a number of other codes or standards.

For instance if this was X100 52" pipe designed to a pipeline code, you could have ~40mm thickness for your 320 bar pipe.

Also at that and any pressure, you don't need to design the pipe to withstand the flange maximum rating, you only need to design it to withstand the pressure it will see. The flanges just come in big steps, but pipe doesn't need to do the same unless the process demands it.

Merry Christmas

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Sawsan311]

Hi littleinch , the required design pressure is actually 320 barg and it is not the flange rating, there would be two options either to follow pipeline code or pressure vessel code.
Note: there is a market limitation in having large piping of such high thickness, manufacturing limitations in how to fabricate the pipe itself.

Regards,

 

[don1980]

Sawsan311, the confusion stems from your indirect and unclear question. As I understand it, you're effectively asking: when is it practical to fabricate according to pipe code (e.g. ASME B31.3) rather than vessel code (e.g. ASME Sec VIII). Is that a correct understanding?

In most cases, this question is only relevant for the design of small containers/vessels - those which can easily and inexpensively be built from readily available pipe and piping components (off-the-shelf schedule pipe and pipe caps). If standard readily available piping components are not suitable, because of the vessel's size or pressure rating, then these incentives (practicality and cost) don't exist.

In some cases, the vessel's service is an additional factor in choosing ASME B31.3 rather than ASME Sec VIII. For example, pump seal pots are generally designed and built according to B31.3 (rather than Sec VIII) in order to avoid the Sec VIII requirement for pressure protection, which is an unnecessary expense of time and money for a seal pot application.

Obviously, it doesn't make sense to consider designing a vessel according to pipe code if the vessel can't be assembled from standard readily-available pipe components.