Demin Water usage

[igorv2]

Hi everyone,
Here is a question from mechanical chap.
Is anyone could advise on usage demin water, untreated (low Ph) and stored in open to atmosphere tank, in conjunction with downstream carbon steel piping and associated equipment? Is this is no-no area and stainless steel is the way to go?

 

[kenvlach]

Emphatic no-no. SS is for high-pressure or hot. 304L mostly.
Most people use plastic, PVC for ordinary usage, or PVDF for critical applications. In old days, glass was used for for distilled water systems.

 

[unclesyd]

What is the material of construction of the tank? An open tank isn’t very good in any service except fire water.

As "kenvlach" states 304/304L S/S is by far the best material for the pipe line. There are far less mechanical (support) problems with S/S. We used both Al and S/S on demin water with the Al giving some support problems with expansion on very hot days. All "pure" lines at the site are now probably S/S.