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I am looking for information concerning the typical application pressure range for 2" Schedule 10 pipe (steel or stainless steel).
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The pressure range depends on the design temperature due to the change in allowable stress.
I've never seen a carbon steel sch10 pipe, always Stainless Steel.
The from code formula for pipe thickness you can determine the max pressure.
HTH
Saludos.
a.
I've never seen a carbon steel sch10 pipe, always Stainless Steel.
The from code formula for pipe thickness you can determine the max pressure.
HTH
Saludos.
a.
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1
- #3
I assume you mean Sch 10S for the stainless steel pipe. I would advise against using it for a number of reasons. Although it may be able to easily withstand the internal pressure of the process, you may come across some serious problems when you do a flexibility analysis of the system. If it ever needs to be able to withstand a vacuum condition, maybe under a steamout condition, it is fairly useless. If you need to weld anything onto the outside of it (pipe shoe, stiffening ring), you need to control the heat input or risk warping the pipe. You will likely need many more pipe supports than if you had gone with Sch 40S, which leads to a cost increase for structural steel. If you are required to apply corrosion allowances to this piping, you will have a difficult time passing any calculations. (I had one situation where a pipe in vacuum service had 95% of the wall thickness used up by corrosion allowance. Very conservative owner.)
My experience is that procurement managers like to propose using Sch 10S piping due to "significant cost savings". They then get big bonuses for saving huge quantities of money. The engineers then get dumped on as being too conservative when they put ridiculous amounts of extra steel in to support all this pipe.
I have only been with my current company for about 1.5 years, but I hear that at the end of every job, we vow never to use Sch 10S again, and then on the next job we get bullied back into using it.
We have used Sch 10 carbon steel piping successfully in a few cases that I can remember, but due to availability, I wonder if it isn't cheaper to go with STD weight pipe most of the time. You will probably end up buying STD weight fittings and then taper boring them to fit Sch 10 piping. Make sure you factor that into your cost.
Most of my bad experiences relate to larger diameter thin wall pipe. By the way, I don't think that carbon steel is generally available as Sch 10 in NPS 2 piping. Maybe it's worth looking at for smaller diameters.
I'd be interested to hear other peoples opinions of thin wall piping...
My experience is that procurement managers like to propose using Sch 10S piping due to "significant cost savings". They then get big bonuses for saving huge quantities of money. The engineers then get dumped on as being too conservative when they put ridiculous amounts of extra steel in to support all this pipe.
I have only been with my current company for about 1.5 years, but I hear that at the end of every job, we vow never to use Sch 10S again, and then on the next job we get bullied back into using it.
We have used Sch 10 carbon steel piping successfully in a few cases that I can remember, but due to availability, I wonder if it isn't cheaper to go with STD weight pipe most of the time. You will probably end up buying STD weight fittings and then taper boring them to fit Sch 10 piping. Make sure you factor that into your cost.
Most of my bad experiences relate to larger diameter thin wall pipe. By the way, I don't think that carbon steel is generally available as Sch 10 in NPS 2 piping. Maybe it's worth looking at for smaller diameters.
I'd be interested to hear other peoples opinions of thin wall piping...
Just a comment!
Not only for pipes and tubes but for everything, the worst thing that we can do is let the salesman and the procurement agent do the design !!
As engineers we have to be sure to have a complete and comprehensive spec when putting out for bid.
I can think of three jobs which had to be completely redesigned after the fact because the original specs didn't have enough detail to allow "flagging" of problems and the salesman was too eager to ask all the questions.
Caveat emptor!
Not only for pipes and tubes but for everything, the worst thing that we can do is let the salesman and the procurement agent do the design !!
As engineers we have to be sure to have a complete and comprehensive spec when putting out for bid.
I can think of three jobs which had to be completely redesigned after the fact because the original specs didn't have enough detail to allow "flagging" of problems and the salesman was too eager to ask all the questions.
Caveat emptor!
I like your comments Flareman. I used to work for a company that was small enough that the engineers did absolutely everything, specifying, procuring, qa/qc on receipt, approval of invoices, etc. (We did have an office manager who wrote the checks to suppliers!) We had INCREDIBLE control over what actually ended up in the final installation.
Now I work for a big company where there is a whole different department who takes care of procurement. Often, what ends up in the field is nothing like what was intended. The big one for us is material substitutions. Too many procurement specialists, with a tiny bit of technical knowledge (if any), approve material substitutions without getting proper engineering input. They write "n/a" next to engineering approval!
I've had procurement managers try to intimidate me into signing purchase orders because NDT of a fabricated fitting was just a "technical issue that could be worked out later". Fortunately, when I got hauled on the carpet in front of my boss later, and asked why I was being so stubborn about approving it, I was able to show him that without the NDT I was proposing, the design didn't meet code.
Well, I feel a little better having got my feelings about procurement off my chest...
Now I work for a big company where there is a whole different department who takes care of procurement. Often, what ends up in the field is nothing like what was intended. The big one for us is material substitutions. Too many procurement specialists, with a tiny bit of technical knowledge (if any), approve material substitutions without getting proper engineering input. They write "n/a" next to engineering approval!
I've had procurement managers try to intimidate me into signing purchase orders because NDT of a fabricated fitting was just a "technical issue that could be worked out later". Fortunately, when I got hauled on the carpet in front of my boss later, and asked why I was being so stubborn about approving it, I was able to show him that without the NDT I was proposing, the design didn't meet code.
Well, I feel a little better having got my feelings about procurement off my chest...
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