PVC, CPVC and SS pipes - Maximum flow speed

[ucabjm]

Dear engineers,

I have the following application:

T: 60-100 F
straight pipe.
Liquid: Seawater
We don't care about friction losses trough the pipe.

I am wondering what is the maximum speed of the water for those kind of pipes.

Thank you

 

[rconner]

If you were to use the "Advanced Search" feature of these forums and a few keywords, I believe you will find there have been many past, similar inquiries with resulting threads/opinions/references concerning flow velocity limitations of plastic pipes. If you vary the keywords some, more past discussions will probably pop up. Also, I believe there have been many past discussions on many Eng-Tips, as well as extensively on NACE forum lists, of various "SS" pipes and e.g. seawater exposures. From past recollections, I believe at least many authorities appear concerned in general about high velocities and plastic pressure pipes (I suspect primarily due to surge/fatigue considerations and possibly other), as well as the effects of chlorides, external soils and/or MIC etc. on at least some "SS". I think whether or not you will have the problems they worry about in your application(s) may have one of those "it depends" type answers (maybe depending on significantly more information than you've provided here).

 

[Artisi]

As friction loss doesn't seem to be a problem (in your estimation) it is therefore irrelevant what the speed (velocity) is - so pick any speed you like, somewhere between zero and the speed of light.

If you need a sensible answer, post the flow rates and pipe diameters under consideration or check previous postings as suggested by rconner.

 

[insult2injury]

Artisi: I disagree, many factors besides pressure drop can limit velocities such as erosion, FAC, solids, etc...

I2I

 

[ucabjm]

I will use 3 inch pipe made of SS, PVC or CPVC.

The problem is that if I increase the speed of the flow too high, it can create a failure in the pipe.

My question is: How fast I can go without risking the integrity of the pipe.

 

[Artisi]

I2I
I was being facetious regarding the velocity and in any case it is seawater - no mention of solids etc.


ucabjm
Still not enough information given, how long is the pipeline, what flowrate are you thinking about - it all makes a difference to the pressure needed for flow thru the pipe and the velocity.

Ask the pipe supplier for the pressure rating of the pipes and any limitation on velocity for seawater.

 

[Pipewrenched]

8fps is the recommended velocity for cold water distrubution for PVC and CPVC piping. Make sure is you use PVC, you install
PVC Pressure pipe and fittings, not dwv.

Engineering and formula's, the backbone to code. Know it and plumb straight.

 

[BigInch]

Keep the velocity less than 8 ft/sec and chances are you won't bust the pipe, but no guarantee with all the information you didn't give.

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain