pitfalls for calc wall thickness piping

[pipewallthickness]

One of the jobs i am working on requires pipe thicknesses calculated, and specified. This is a bit strange for me as I am used to specify ANSI schedule pipe for B16.5 flange ratings, etc. I am aware of the method to calculate wall thicknesses, adding corrosion allowances, etc. But specifying calc wall piping raises questions in my mind. What happens to standard flange IDs, etc.

Can someone shed some light on this?

email: dilipmeena@yahoo.com

of course we are talking about 300 lb and up piping classes.

 

[JohnBreen]

Hello,

Would you please restate your questions? I am sorry, but I am not sure that I understand exactly what you are asking.

Thanks, John.

 

[JohnBreen]

Hello,

In general you should refer to the AMSE B31.3 Code for Process Pipin, Part 2, paragraph 302 and its sub-paragraphs.

Regards, John.

 

[rajagopalan1]

Hi,

If my understanding is correct there is no standard
thickness (at the welding end to the pipe (weldneck flange)) for flanges. It depends on the thickness of the matching pipe and you always have to specify the matching pipe thickness in case of weld neck flanges, if that is what you are refering to,to buy the correct flange.

As far as thickness calculations are concerened you can follow the std procedure as mentioned by John. Do remember to consider manufacturing tolerance.

Raja

 

[Dikkala]

You should calculate the thickness of the pipe for the specified service. Then add manufacturing tolerance on thickness. Then you check the standard schedule numbers of pipes available in the market. Go for the schedule giving the next higher thickness of the pipe you want.

That is why calculated thickness is required.