Max Allowable Working Pressure for Welded & Npt Piping 2

[DTC]

I would like to find a full updated chart for the maximum
allowable working pressure for welded and threaded carbon
steel pipe (all sizes & schedules) with corrosion factors from 0 CA to 1/4" CA

 

[MikeONeill]

Without performing specific B31.1 calcs, this sample is easy to set-up in excel, and is reasonably close. As for corrosion allowance, I cannot remember ever seeing a chart.

Regards,

Mike

6" SCHEDULE 10 ASTM A53 GRADE B TYPE E (ERW) PIPE

P = (2St) / D

P = PRESSURE (PSIG)
S = STRESS (FOR A53 GRADE B - 35Ksi)
t = NOMINAL WALL THICKNESS (INCHES)
D = OUTSIDE DIAMETER (INCHES)

(2*35,000) = 70,000
70,000 * .134 = 9,380
9,380 / 6.625 = 1,415
P = 1,415

'S' REDUCED BY A DESIGN FACTOR OF .72 WILL PRODUCE THEORETICAL MAXIMUM ALLOWABLE OPERATING PRESSURE (MAOP)

(2)(35,000*.72) = 50,400
50,400 * .134 = 6,753
6,753 / 6.625 = 1,019
P = 1,019

APPLY A JOINT EFFICIENCY FACTOR OF .85 FOR ERW PIPE, P = 866 PSIG
(MILL HYDROSTATIC TESTING IS PERFORMED AT 850 PSIG)

 

[MJCronin]

DTC

I take issue with the above calculation.... ASME B31.1 or B31.3 should be the governing code for your operations and in both of these codes, the allowable stress is decreased as the operating temperature of the line increases. (see paragraph 104)

What you really have to do is to develop an organized set of pipe specifications (sometimes called line specifications) for each kind of fluid service. In each spec, piping, flanges, valves and gaskets are selected as per maximum combinations of temperature and pressure. ANSI B16.9 pipe fleanges typicall limit the service pressure for most systems....

Hope that this helps...... good luck !!! MJC

 

[MikeONeill]

MJC's point is well taken, I neglected to state at ambient temp. Again, not knowing the specific stress value (using minimum) of the pipe and without developing a line spec, the calc above will get you close at ambient temp.

I believe flanges are B16.5

Mike

 

[tstead]

Cast iron flanges are B16.1 - all others are B16.5

Tim S.

 

[PAN]

Refer to the sample calculation ,I understand that the allowable stress of A53 Gr.B (from B31.1) is less than 35 ksi. Please comment.

PAN

 

[UtilityLouie]

A chart that I have seen that takes into account temperature is in the NAVCO piping datalog. The latest edition of this book that I have found is #11 published in 1984. In my opinion it will get you close to the information that you need, but detailed calculations are always recommended. It is an excellent piping handbook.

I had to locate this book on a used book website. At this time I cannot remember which one it was. It was a Canadian company.

 

[br549]

You have talkd about pipe but in most instances the rating of you flanges is the limitng factor of your piping system.

These rating are based on leakage as well as pressure contament, leakage typically being the controling factor.

 

Piping Spreadsheet Templates
for Piping Engineer

Program
PipingOffice (full suite) Single User - I.D.

Capability
Pipingoffice is a set of Microsoft Excel-97 compatible spreadsheets for performing various piping engineering calculations. Following are included: Pipe Allowable Pressure per ASME B31.3; Pipe Allowable Pressure per ASME B31.1; Pipe Branch Reinforcement per ASME B31.3; Pipe Branch Reinforcement per ASME B31.1; Steam Safety Valve Reaction Effects per ASME B31.1 Appendix II; Pipe Mitered Elbow Allowable Pressure per ASME B31.3; Piping Properties; Pipe Support Span, Shoe Bearing, Jacketed Pipe Weight; Pipe Theoretical External Collapse Pressure; Pipe Allowable Pressure per ASME B31.3 Chapter IX High Pressure; Extruded Outlet Pipe Branch Allowable Pressure per ASME B31.3; Piping Line Blinds Design; Metal Weight Data; Physical Properties of Pipe; and 3D Offset Calculator

Hardware
For computer compatible with Microsoft Excel-97 or later.

Developer
Ben A. Nottingham

 

[Ben4piping]

Using ASME B31 Piping Codes, the design wall thickness is normally determined by: t = nominal wall thickness - mill tolerance on thickness - corrosion allowance - erosion allowance - mechanical allowances, such as threading or grooving. Pipe may be ordered with a minimum wall thickness, in which case mill tolerance would = 0. Mill tolerance is normally 12.5 percent for steel, alloy steel, stainless steel, and aluminum pipe. Stainless pipes made from plate have a mill tolerance of 0.010 inch as stated in ASTMs. Mill tolerance for copper pipe varies by ASTM. Threading allowance is dimension h as determined by ASME B1.20.1. I've had a blast putting all this together in Excel spreadsheets according to B31.3 and B31.1.

 

[kahlilj]

ben4piping,
is it possible to get a copy of this spreadsheet that you mentioned? or can u tell me how i can put one together?
thanks,

 

Hello Kahlilj,

Ben (ben4piping) is being far too modest. Ben's PipingOffice suite of ExCel spread sheet templates are far more useful than he describes in this thread. The suite has saved me an enormous amount of time through the years. Some of the capability of the suite includes the following:

Pipe Allowable Pressure per B31.3
High Pressure Pipe per B31.3 Ch-IX
Pipe Allowable Pressure per B31.1
Branch Reinf per B31.3
Branch Reinf per B31.1
Mitered Ell per B31.3
Mitered Ell per B31.1
Safety Valve Reactions per B31.1 Appendix II, (impact forces)
Support Span, Shoe Bearing, ....
SIFs per B31.3
SIFs per B31.1
Theoretical External Collapse Pressure
Jacketed Pipe Theoretical Column Buckling
Pipe Dimensional and Material Properties
3-D offset, Triangle Calcs, Dimen Calcs

You can contact Ben at:

bnottingham@chartertn.net

Regards, John.