pipe rating calculation? 2

[johnmam]

the question is:

How can I calculate the pressure-temperature curve, to do the piping material specification, for a service of a power plant according to ASME B31.1?

thanks in advanced.

 

[JohnBreen]

Hello johnmam,

I am sorry but it is not clear to me what you mean by "calculate the pressure-temperature curve".

Most power plants have developed piping system material standards for all thier ranges of service pressures / temperatures. They will require thier standards to be followed.

If such standards are not available, I think you should determine what the maximum expected temperature will be for each of the piping systems at issue and go into B31.1, Appendix A, to see what considerations will set the maximum temperatures allowed for materials. If you can find Bednars's book on pressure vessel design you will (surprise!) find material tables near the back of the book that will guide you in chosing approriate materials for pipe, and piping components for vrious pressures / temperatures.

http://www.amazon.com/Pressure-Vessel-Design-Handbook-Bednar/dp/089464503X

Regards, John.

 

[NozzleTwister]

johnmam,

I think a curve would be tough unless it had a specific, narrowly defined use.

A number of years ago, I was tagged to update all the clients pipe specs for a major refinery expansion and write new specs as required. The client wanted as part of the spec package, tables showing the maximum allowable pressure for each pipe size and temperature for each pipe spec.

I created tables with temperatures increasing up the page vertical and the pipe sizes across the bottom. We wrote a program in Basic that would run all of the calcs and printed out a table on an old dot-matrix printer.

While some of our clients wanted all pipe specs to be flange limiting, that's not always practical or economical especially if the lesser wall thickness is just a few PSI short of the flange limit and the majority of your services are below that anyway.

That was the approach this client took so the table showed the lesser of the flange allowable or pipe allowable.

Creating the data bases for the program was very tedious.

I'm sure programs like this are available to do that today in Excel. If you use one, make sure the data bases are correct. With the some allowables and flange ratings changing in every code update it is important to verify your data and check the answers. Note that any table or curve you create today may not be valid in the future if the allowables change.

Good luck,

NozzleTwister
Houston, Texas

 

[johnmam]

thanks for the replies, I,ve been studing about the information you give me and I could make clear my mind.I didn,t get Bednars's book but I,ve find some similar ones that I`m reading.

piping and pipeline engineering(George A.Antaki.)
Design of piping systems-(Mw kellogs)
piping handbook(mohinder L.Nayyar)
and some material specifications examples

what`s your opinion about this books if you know some of these?

I have know I new question, it´s a general one

In a process plant projet, refering to piping, which are the diferents parts of study, I mean material specificaton, PFD, PIDs, stress analisys. There are some mores?

And which are the software that I´d need for developed a piping detail design?

thanks in advanced,
johnmam.