Designing High-Pressure Pipes

Mikerho is right. You're not up to it.

Mike if you're not going to help, not scold. I imagine that you are the only competent professional.

Thanks aurizon,

You probably know more about this subject than I do, from reading your past posts - you brought up some very good points.

GA from me

(somebody else please follow up!)

Mike

Just did!

Hi Omar,

I'm not scolding. You should not take this personally. The process conditions you have described can cause a very unpleasant incident if a pipe or flange fails. This could cost someone the use of certain parts of their body or even their life. If anything, you should be thanking me for trying to look out for you.

By the way, what are your engineering qualifications? Are you in management?

Best Regards,

Mike

Open a dialogue with a piping distributor, or several of them, without delay.

This is the matter of the inside, but in te calculation it is outside diameter of the pipe, its material quality and temperature of the medium in the pipe. Also it is for the designer to estimate the adition for corrosion and the imperfection of the pipe make. This matter is under ASME piping rules and don't play with this matter specially if the medium is gasous or inflammable and choking in close space.

Best regards,

Marijan from Zagreb

Omar go to ASME B-31 3 Chapter IX (Seccions K). Take special attention to Valves, Gaskets and INSULATION (Hot Oil Requires are very specific).

To give you some idea. Pipe has been made for high pressure for well over 150 years. due to experience, failures, deaths etc a number of regulatory bodies have emerged. The names vary from country to country, but they deal with standards, for wire, pipe etc.

http://www.asme.org/

http://www.astm.org/

there will be a listing of standards for pipe etc, for various pressures, temperatures etc. These manuals, often called pipe schedules, for pipe, wire schedules for wire, and steel beams and cement and so on.

These schedules list the pipe by material, wall thickness, application, and all manner of ways pipe, wire etc is sold. These schedules are are used by professional people to design pipeing, wiring etc that will have a long and safe life and will be an efficient use of materials. There is no point in wasting money with overdesign, nor can you save money and take great risks with underdesign. The people who use them have spent years learning and using them, and getting the experience to use them with safety.

That said, an intelligent person can read the standards and learn how to use them for particular applications fairly easily. Where it gets hard is in the extreme applications. water pipe for a house = dead easy. Boiler piping or hot oil piping at 700F and 3000 PSI = not easy. Vessels that explode at those temperatures and pressures do so with such force that people are shredded into cooked fragments. It is an ultrasonic shock wave that fluidizes flesh, like a bomb blast does to the close by victims, so you do not want any learners doing it. read deep into the links and you will get some idea.

http://www.google.ca/search?hl=en&safe=off&q=ASme+%2B%22pipe+schedules%22&btnG=Search&meta=

http://www.google.ca/search?hl=en&safe=off&q=ASTM+%2B%22pipe+schedules%22&btnG=Search&meta=

http://www.google.ca/search?hl=en&safe=off&q=ASTM+%2B%22wire+schedules%22&btnG=Search&meta=

Much more in-depth than your earlier post and spot-on.

Out of curiousity, what's your background?

Mike

Try to solve the problem by selecting a seamless austenitic stainless steel pipe material in accordance with ASME pipe material SA 312 with the optimum grade to withstand pressure, temperature and corrosion, and try to find the required pipe wall thickness and compare with that of SA106 Grade B.

Complete explain about this, not to much more to say. May be only: What about PWHT, using A 106 and what if Sa 312 (SS) is selected? Very good Mr Adbel

Now that is what I call a whole set of very good answers from Mr. Abdel Halim Galala my friend. I have never gave the same poster three GA's at once but I believe you deserve them for those answers. While some would not even answer the posters question and automatically assumed that the OP shouldn't even ask such a question because of safety worries you answered the question exactly and delivered better than most. Your knowledge of the ASME codes is truly impressive. I personally have never worked on the design side of such high temp. and pressure oil other than maybe fitting and welding on high pressure pipe in refineries and chemical plants in my earlier days. Most of my ASME design and stamp implementation experience is with up to 1500 PSI steam in power generation and paper mills. We never see pipe systems with anywhere near those kinds of pressures.

The safety issue with this question is huge and like the others have already said any one wrong move in any aspect of designing, installing, maintaining and operating such a system could be devastating to anyone and/or anything around it. I am not sure why anyone would even want to put an oil under that pressure and temp. and then contain it in a pipe around someone or something living. I was wondering if anyone could give me an example of what would this or a similar high pressure pipe system be used for?

I have been torn between voicing my opinion and staying quiet, and the opinioniated side has won out -

I do not want to come across as demeaning/condescending/ etc ...... because I truly do respect Mr. Galala's knowledge and expertise, plus his ability and desire to help others out. However, I believe that a little knowledge is a dangerous thing!!

This thread only covers one aspect of piping design; what has been left out for a proper/thorough design is, and not limited to: branch connections, welding, NDE, pressure testing, supports, local stresses, thermal expansion, wind, seismic, fatigue, bolting, ........

700 degree F & 3000 psi oil is not for the faint of heart.

My sentiments exactly!

I grant you that 700 deg.f and 3000 psi is nothing to sneeze at, but deep submergence vehicles go to much higher pressure. Also, fluids are tame compared to gas. We routinely test gas cylinders at more than 3000 psi. Others test at twice this pressure and firearms develop more than 10 times this pressure. Also, the race is on to develop portable high pressure hydrogen storage for automobiles. We might as well get used to the fact that the world is becoming a more dangerous place.

Fair enough, and partly true -

I would hazard a guess that 700 F is above the atmospheric boiling point of the oil, and because of that, if a leak developed it would instantaneously flash into vapour (a highly explosive vapour at that); and 700 F is almost assuredly above the fire point of that oil. And possibly over the autoignition temperature.

Note: I work around an operating pressure of 5500 psig syngas - 75% hydrogen.

And I am not talking about small lab scale stuff - I am talking about a few of these smaller beasts for our pressures/volume:

*******

Plus a couple larger 10 cylinder monsters.

I think this is the kind of answer the OP need.

Another great explanation from a great guru.

Brilliant answer Abdel! Up to your usual high standard.

You don't state how much of this pipe you require, but if it's a short length, I suggest you locate a surplus 76mm cannon barrel.

Thanks to all who expressed their support especially Mr Abdel. Obviously I know than the process conditions can cause a very unpleasant incident if a pipe or flange fails. I just wanted to know which factors could miss out.

This is only the beginning...

I would assume that somewhere, this section of pipe is to be connected to a flange of some sort. Therefore:

• the proper gaskets would need to be selected,
• adequate flanges would need to be chosen,
• bolt material must be defined,
• bolt loads would have to be calculated,
• applicable and precise bolting methods would have to be specified and,
• a Bolting Operation QA process would have to be implemented

It's much more fun than simply designing the pipe