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Maxamillion
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Join Date: Aug 2007
Location: Southern Ontario, Canada
Posts: 9

High Pressure Steam Pipe

08/16/2007 11:34 AM

Should high pressure steam pipe be seamless schedule 80?
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Anonymous Poster
#1

Re: High Pressure Steam Pipe

08/16/2007 11:36 AM

Please state the temperature, pressure and flowrate of the steam.
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HydroScot
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Join Date: Jan 2007
Location: Scotland
Posts: 154
#2
In reply to #1

Re: High Pressure Steam Pipe

08/17/2007 7:08 AM

Pressure rating will depend upon bore size and materials according to API standards.

You can alsocheck your local pipe suppliers
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Anonymous Poster
#12
In reply to #1

Re: High Pressure Steam Pipe

05/04/2010 2:10 PM

super heated steam pressure = 93 bars

temperature of this steam = 535 deg c

flow rate = 64000 kgs per second
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pipewelder
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Location: North Georgia, USA
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#3

Re: High Pressure Steam Pipe

08/17/2007 8:50 AM

To select the proper pipe you will need to know the pressure and temp. of the steam. You may not need to use sch. 80 if you use seamless pipe and the pressure and steam is not over the design ratings. You may need sch. 100 or larger and/or you may need to go to a chrome-moly type alloy if the temp. and/or pressure is over a certain point. ASME B31.1 is the code that sets the rules on installing steam piping and in my opinion should be used to determine everything related to running steam pipe.

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Ried
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Join Date: Dec 2005
Posts: 1602
Good Answers: 19
#4
In reply to #3

Re: High Pressure Steam Pipe

08/17/2007 9:55 AM

Selection of pipe size and schedule should also factor the location of installation, expectation for corrosion, and safety. If you're using the pipe for heating a dip tank, there might be replacement costs that are minimized by using a thicker pipe.

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Maxamillion
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Join Date: Aug 2007
Location: Southern Ontario, Canada
Posts: 9
#6
In reply to #3

Re: High Pressure Steam Pipe

08/17/2007 4:30 PM

Thanks
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Maxamillion
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Join Date: Aug 2007
Location: Southern Ontario, Canada
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#7
In reply to #3

Re: High Pressure Steam Pipe

08/17/2007 4:31 PM

Thanks for information!
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Ferrari_Guy
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Engineering Fields - Piping Design Engineering - New Member

Join Date: Jul 2007
Location: Vegas Baby
Posts: 29
Good Answers: 2
#5

Re: High Pressure Steam Pipe

08/17/2007 11:30 AM

It will also depend on the method of jointing. If the pipe is to threaded, B31.1 requires a certain amount of pipe wall left after the threading. We spec Sch. 80 pipe for small sizes where threaded, Sch. 40 if it is to be socket or butt welded. Good old A53 is good to about 500 PSIG in most applications. FG
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Maxamillion
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Location: Southern Ontario, Canada
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#8
In reply to #5

Re: High Pressure Steam Pipe

08/17/2007 4:32 PM

Thanks thats good advice!
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Abdel Halim Galala
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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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Location: Cairo, Egypt
Posts: 1733
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#9

Re: High Pressure Steam Pipe

09/03/2007 1:59 PM

The pipe wall thickness used for steam is determined from the applicable formula of the pertinent ASME B31.1, Power Piping. Please fellow the following example :

Given : Code : ASME B31.1

Design Pressure (P) : 13 bar (188.5 psi), [oper. press. 10 bar (145 psi)]

Design Temperature : 180 oC (356 oF), [oper. temp. 150 oC (302 oF)]

Material : ASTM A106 Grade B, Seamless

Nominal Pipe Size : 3 inch

Find : Minimum Theoretical Wall Thickness, tm & Minimum Nominal Wall Thickness, t

Data : tm = P Do / (2 S + 2y P) + C (ASME Code B31.1)

Corrosion Allowance, C = 3 mm (0.11811 in.)

Factor, y = 0.4 (for carbon steel) [ASME Code B31.1, Table 104.1.2(A)]

Joint efficiency, E = 1.0 (for seamless pipe E=1)

Pipe Outside Diameter, Do = 3.5 inch

Allowable Tensile strength, S @ 356 oF=15000 psi (ASME B31.1,Table A-1)

Wall Thickness Tolerance = 12.5% (ASME B36.10 & ASTM A106)

Solution : By substitution into equation,

tm = P Do / (2 S + 2y P) + C

= (188.5 psi)(3.5 inch)/(2*15000 psi +2*0.4*188.5 psi) + 0.11811 inch

= 0.14 inch (3.6 mm)

Which is the theoretical minimum for wall thickness without allowing for wall thickness tolerance.

Thickness adjusted for wall thickness tolerance, t = tm / (100%-12.5%)

= 0.14 inch/(1-0.125)=0.14/0.875= 0.16 inch (4.06 mm)

The next greater commercial wall thickness is found from ASME B36.10 to be 0.216 inch (5.49 mm) which corresponds to 3" Sch. 40.

In other words 0.216 inch nominal pipe wall thickness is the commercial wall which, when reduced by the full tolerance of 12.5%, satisfies the code formula for tm.

You can fellow the same scenario using the exact design pressure P taking into consideration the value of allowable tensile strength S of seamless pipe material ASTM A106 Grade B at design temp.

So, determining the pipe wall thickness (or Sch.) depends on Design Pressure, Design Temp., Type of Material and its Allowable Tensile Strength, and Pipe Outside Diam.

We prefer using of Seamless pipe for its high strength (E=1) compared with Seam Welded pipes (E < 1).

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Anonymous Poster
#11
In reply to #9

Re: High Pressure Steam Pipe

10/16/2009 3:27 AM

my question is how to determine

design pressure & temperature

if we know

1. operating pressure

2. operating temperature, for this i had refer ASME b31.3-2004,clause 301.3.2
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pipewelder
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Location: North Georgia, USA
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#13
In reply to #9

Re: High Pressure Steam Pipe

05/04/2010 5:54 PM

Nice good answer covered all the question and more with that answer as well.

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Anonymous Poster
#10

Re: High Pressure Steam Pipe

09/11/2007 8:55 AM

If it is VHP line u have to use the following,

ASTM A335-P22,SMLS,SCH 160 to XXS, 2 1/4 CR-1Mo.

If HP the following,

ASTM 106 Gr B,SMLS,SCH 80
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13 comments

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Users who posted comments:

Abdel Halim Galala (1); Anonymous Poster (4); Ferrari_Guy (1); HydroScot (1); Maxamillion (3); pipewelder (2); Ried (1)

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