Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
(OP)
I'm specifying an elevated tank repainting. Right now, I'm going with AWWA Interior Coating System #5 (ICS-5) for the interior wet area of the tank. ICS-5 consists of a zinc-rich primer and epoxy intermediate and finish coats. All paints must be ANSI/NSF Standard 61 approved for immersion in potable water.
Honestly, I know very little about paint. The ICS-5 was initially chosen based on a recommendation from a paint manufacturer. However, I just talked to a different manufacturer who said that they did not make a zinc primer that's NSF 61 approved. She said the reason for this wasn't because they weren't capable of doing so - they have a zinc primer for exterior use - but rather, they do not support the use of zinc as a primer for potable water immersion systems. This manufacturer is concerned that subsequent coats could be compromised and leave the zinc primer exposed to potable water, and in the future zinc will become the "new lead".
Just wondering if anyone shares or has heard this viewpoint.
Thanks in advance for your help.
Honestly, I know very little about paint. The ICS-5 was initially chosen based on a recommendation from a paint manufacturer. However, I just talked to a different manufacturer who said that they did not make a zinc primer that's NSF 61 approved. She said the reason for this wasn't because they weren't capable of doing so - they have a zinc primer for exterior use - but rather, they do not support the use of zinc as a primer for potable water immersion systems. This manufacturer is concerned that subsequent coats could be compromised and leave the zinc primer exposed to potable water, and in the future zinc will become the "new lead".
Just wondering if anyone shares or has heard this viewpoint.
Thanks in advance for your help.





RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
http://www.nlm.nih.gov/medlineplus/ency/article/00...
http://en.wikipedia.org/wiki/Zinc_toxicity
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RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
Basically, they say that specifying topcoated zinc underwater is poor practice. Eventually, the topcoat will be compromised and the zinc primer will be exposed to water. When it is exposed to water, it reacts and forms blisters, causing the system to fail.
This is the complete opposite stance I've heard from other manufacturers, who claim that a three coat system with a zinc primer is the "Cadillac" of paint systems, and should definitely be specified for tank interiors.
Thoughts?
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
And in the older galvanized pipe had lead in the zinc coating.
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
This is a repainting, so you wouldn't use an inorganic zinc primer.
I suggest that the coatings supplier who rubbished the idea of a zinc rich primer was simply trying to push her product.
This is the one I would research and probably use:
https://www.tnemec.com/product/view/Series-94-H2O-...
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
There are some concerns about using any solventborne coating inside potable water tanks due to water odor/taste problems - with your suggested material, the PCBTF solvent has a particularly pungent odor. The first time I had a paint with that solvent sprayed out at the steel fab, the paint crew commented on that several times.
Again, a competent crew (no over-thick application, no thinning, forced ventilation in the tank during cure) can overcome that challenge.
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
It is a little strange, but we have one water tank that is still coated with Anhydrous Lanolin
http://www.targetproducts.com/prod-detail.aspx?id=...
http://www.google.com/url?sa=t&rct=j&q=coa...
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?
RE: Zinc Primer for Potable Water Tank - Will Zinc Become the "New Lead"?