Steam pipe Pressure rating 2

[62hog]

I am wanting to use Sch 10s stainless steel pipe for a steam system. Can anyone give me some insight for where I might find a Temperature and Pressure chart that would include 200 psig steam or about 400 deg F?

Thanks.

 

[buddyo1]

I am not aware of a pressure/temp. charts for stnls stl Sch 10 pipe. I calc the wall thick. press limits per the applicable code requirements. I work in the utillity boiler field and use either the ASME sec. 1, or B31.1 code equations. P=2SE(tm-A)/Do-2y(tm-A), P=allowable press. SE=B31.1 allowable stress for material per temp, tm=wall thick, Do=outside diameter,y=a coefficient (for type of steel and temp. you would use .4)
A=additional thickness for corrsion and/or end preping (threading or any process that thins the wall) See page 16 of the ASME B31.1-2001 code. (You did not state what type of stnls stl or size pipe you are using.)I used A312 TP304 which has an allowable of 11000 psi @ 400F P=2*11000*(.120-.01)/4.5-2*.4*(.120-.01) P=538psi, Remember this needs to be adjusted for manufacturing tolerance of 12.5%. I hope this helps you to be able to size other pipe walls.

 

[62hog]

Thanks Buddyo1.

You made the correct assumptions about material and pipe size.

This helps alot.

 

[TD2K]

62Hog, if you are going to use that pipe, the calculation of its pressure capacity should be done by someone qualified in your organization.

This isn't a negative comment against buddy01's response (it seems to be well laid out though I don't do these calcs) but from your point of view, if something happens, saying 'well, someone off the Internet said it was okay' is not going to satisfy very many people.

This just doesn't sit right with me. I know running the calc(s) from the appropriate code isn't rocket science but we are talking about steam at 200 psig, Eng-Tips isn't the correct forum to be 'okaying' these type of questions IMO.

 

[BobPE]

TD2K:

You are right on target with your comment and I couldn't agree with you more. The is a forum where we can talk, not dispense advice. I have the same concerns as you when I read it, buddy01 gave a great discussion, but it should not be construed as engineering advice.

BobPE

 

[buddyo1]

I also agree that someone qualified from your orginization should be sizing the pipe. My intent was for you to go to the correct code and see what the requirments are for your application. There should be some design standards, or code requirments that you must follow. Most steam systems are designed under the Power Piping Code B31.1, that is why I referenced it. Read page 16 trough 18 of the ASME B31.1-2001 code.

 

[62hog]

All of this was taken as you have written. Being in the consulting business, I am used to collecting information and analyzing and utilizing it as appropriate.

Thanks for all of the additional advice and concern.

 

[MJCronin]

TD2K,

You are "right on" with your observations about advice and information given on this forum.

I feel that it is appropriate to point out governing Codes,standards, books, texts and websites, but an actual calculation or soulution is usually a bad idea.

Leading someone in the right direction is much more useful than doing actual engineering analysis online ( Also much less risky....)

Performing analysis and problem solving online only leads to abuse and disrespect for the engineer(s) posting answers (Its kinda like trying to be nice to an ungrateful wife...)

I would like the comments of others on this issue...

MJC

 

[TD2K]

"... but an actual calculation or solution is usually a bad idea."

Why do I feel like the back of my neck is burning? . Valid point though MJC.

 

[hacksaw]

buddyo1,

I agree with you for piping in the powerhouse and on the boiler, but in operating plants B31.3 seems to be the most common.

 

[TBP]

dacksaw - it may depend upon the jurisdiction. In Ontario, B31.1 covers steam, compressed air, high pressure water, etc in entire plants in general industry. B31.3 covers non boiler room utility piping in operations like refineries, pulp & paper, petro-chem, etc.

 

[hacksaw]

TBP,

You have stated much better than my attempt, although I have not seen B31.1 used with compressed air.

By operating plants I meant to have indicated process plants. The transition from 31.1 to 31.3 is an engineering call. That we agree upon.

Thanks,