5 replies to this topic

[cowboys5xsbs]

I am trying to find piping sizes up to 6” and material which will handle 6000 MAWP and burst 7500psig minimum.  Temperature range will be between 0-175F.

[Art Montemayor]

You should specify what your pressure units are in order to have our members respond with confidence that they are dealing with your query accurately.  What units do you mean by writing “6000 MAWP”??  (MAWP = Maximum Allowable Working Pressure)  This is what happens when you use acronyms without defining them.

 

The diameter of the pipe does not limit the working pressure.  It is the pipe’s alloy and the pipe’s wall thickness (using seamless pipe).  Additionally, the pipe’s wall may not be the limiting factor; the type of joint and welding will also limit the maximum working pressure.

[cowboys5xsbs]

You should specify what your pressure units are in order to have our members respond with confidence that they are dealing with your query accurately.  What units do you mean by writing “6000 MAWP”??  (MAWP = Maximum Allowable Working Pressure)  This is what happens when you use acronyms without defining them.

 

The diameter of the pipe does not limit the working pressure.  It is the pipe’s alloy and the pipe’s wall thickness (using seamless pipe).  Additionally, the pipe’s wall may not be the limiting factor; the type of joint and welding will also limit the maximum working pressure.

All pressures in PSIG

[MTumack]

For SA-106-B:

 

If I recall correctly I believe SCH XXH is good up to 1-1/2". After that you're probably looking at custom pipe, you'll need to calculate the required thickness as per B31.3. para 304.1.1 and para 304.1.2. Ensure you include the required corrosion allowances as per the code as well as the required mill tolerances as per your manufacturers fabrication process.

 

May I ask, what do you need this pressure for? This kind of pressure is no to be messed around with.

 

Art: The Diameter of a pipe does in fact limit the working pressure allowable, it changes the hoop stresses quite a bit; a .5" WT 2" OD pipe is good to a much higher MAWP than a 0.5" WT 24" OD pipe.

Edited by MTumack, 15 January 2015 - 01:21 PM.

[Art Montemayor]

Mtumack:

 

What I said is true.  If you employ a larger pipe, you simply go to a higher wall thickness.  I did not state that I was maintaining the wall thickness constant.

 

As you state, the hoop stress is what determines the mechanical strength of a given pipe with a given wall thickness and diameter.  You are not expected to vary both diameter and wall thickness.  The pipe diameter is calculated for a specific flow rate - be it gas or liquid flow.   Once you obtain the desired nominal pipe diameter size, you then proceed to determine the required thickness to withstand the stated pressure.  And it is this second step that the OP obviously is debating - not the size of the pipe.

 

The pipe size calculation is a process calculation.

The pipe wall thickness is a mechanical calculation.

[shan]

Piping Class API 10000 per API 6A