CS or maybe SS using

[Asya]

The RSI value of RO permeate is specified from 11 to 15.8. This value means as “severe corrosion”.
Further to the review of RSI, unexpected corrosion product and scale particle may affect to the operation and maintenance of demineralization package. pls advice me whether carbon steel is appropriate or not. if not why?

 

[blriehl]

Need more information. RSI is a conglomerate value. Do you have a real water analysis?

And by carbon steel, do you mean black pipe? Or seamless? Or welded? Need more info to help.

Bill Riehl
Riehl Engineering

 

[bimr]

Carbon steel is not appropriate for RO permeate. RO permeate typically has a pH of 5-6 with the lower pH (acidic) due to carbon dioxide dissolved in the water. This will corrode carbon steel.

One option is to use Schedule 80 PVC piping & fittings. A second option is to use 316 stainless steel piping and fittings. A third option is FRP.

 

[EdStainless]

and it depends on the pressure, Many systems use FRP. I like that option better than metal.

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P.E. Metallurgy, Plymouth Tube