Stainless steel clean steam piping design guidelines???

[brosebor]

Can anyone point me to a reference for the specification of a stainless steel piping system for a 65 psig clean steam system?

I've already done the design including pipe sizing, traps, etc. What I need is information on recommended pipe schedules, if tubing is more appropriate than pipe, etc.

The material will be 316L to prevent corrosion and rouging.

The steam is generated from deionized water.

Thanks

 

[ione]

Use Barlow formula to calculate the pipe thickness:

t = f * P*D/(2*S)

t = wall thickness (inches)
f = safety factor
P = internal design pressure (psi)
D = outside diameter
S = allowable stress for your material at your design temperature (psi). For stainless steel ASTM A312 TP316L the value of allowable stress is 16700 psi (roughly)

Then, when you get the pipe thickness from the formula above, you can easily find the pipe schedule suitable for your application.

 

[brosebor]

Thanks Ione.

What I'm looking for more specifically is a guideline(s) relating to standard industry practice. For instance, I could use tubing (of differing wall thicknesses), schedule 10, or schedule 40 piping, etc.

Are there cost or availability issues that need to be considered? Installation issues?

Since tubing is thinner than piping, are there erosion issues that could come into play?

Thanks

 

[C2it]

A ruptured steam system can spoil your day. You might think about employing a competent piping engineer to spec out your system.

 

[VerneE]

It appears you are looking for specs for sanitary piping and tubing systems that are used in drug manufacturing, dairies, and food processing. ASTM A270 is the standard for "Seamless and Welded Austenitic Steel Sanitary Tubing". You can also look at various manufacturers of sanitary piping systems, like TriClover AlfaLaval, Cherry Burrel, and many others. Most of those have catalogs that help in the design of piping systems. There are requirements for valves and such to not have crevices and dead spaces that could allow for the collection or build-up of organisms that would contaminate the piping system. There are also requirements for surface finish of the interior piping systems.

In my experience, the mill tolerances and corrosion thickness requirements for the piping are more than the thickness needed for the pressure, e.g. for 150# steam the tube only needs to be the thickness of paper for 2" pipe. However, vacuum pressures also could be a factor, otherwise the system will collapse when it cools off.

 

[HEC]

Brosebore, in general design the system such that it is free draining and will not trap or contain condensate anywhere. Cleaning and initial passivation of the system is paramount, this should be covered by the installation qualification procedures. It is a pressure system an must therefore be designed according to you country codes for pressure piping. A useful reference would be ISPE.
What is the steam to be used for?

Mark Hutton