Flange Isolation Kit
Flange Isolation Kit
(OP)
Gents,
I would like to know when a flange isolation kit is required when installing a SS valve into a CS line. The system is Hot Process Water built to B31.3. The valve is 18" butterfly.
Regards
79ron79
I would like to know when a flange isolation kit is required when installing a SS valve into a CS line. The system is Hot Process Water built to B31.3. The valve is 18" butterfly.
Regards
79ron79





RE: Flange Isolation Kit
RE: Flange Isolation Kit
Can you please explain why not? People here seem to believe when a CS flange meets SS, we need an insulation kit there due to dissimilar metals, hence galvanic corrosion.
Cheers,
YY
RE: Flange Isolation Kit
RE: Flange Isolation Kit
But, the reason for this is contained in the position of the metals in the galvanic series.
Carbon steel/stainless steel are considered to be "not that far apart" galvanically.
Whereas copper/zinc are considered "significantly far apart"......and you can make a battery.
http://www.corrosionsource.com/FreeContent/1/Galva...
MJCronin
Sr. Process Engineer
Venture Engineering & Construction
www.VentureEngr.com
RE: Flange Isolation Kit
However if you put a small piece of C Stl connected to a wholly Stl Stl system then it could suffer significant galvanic corrosion.
I might have got the anode and cathode but the wrong way round, the theory is still valid.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Flange Isolation Kit
Ag = -0.15V
SS = -0.50V plates all the above
CS = -0.85V plates all the above
Al = -0.95V plates all the above
Galvanized Zn = -1.2V plates all the above
Zn = -1.25V plates all the above reasonably well
Mg = -1.75V plates all the above very well
Difference between CS and SS is 0.15 or greater, so they really should not be placed together, however if they are, electron flow will be from most negative to less negative, the CS will plate the SS. If you put the two together, put a small bit of SS in contact with a large surface area of CS.
Lesson learned. DO NOT put SS "silverware" in the dishwasher with the real silverware. Both will not come out looking very nice.
I hate Windowz 8!!!!
RE: Flange Isolation Kit
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Flange Isolation Kit
I hate Windowz 8!!!!
RE: Flange Isolation Kit
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Flange Isolation Kit
I hate Windowz 8!!!!
RE: Flange Isolation Kit
*Not recommended in flammable services.