In both the industrial coatings and water infrastructure industries, there has recently been significant buzz about upcoming changes to potable water lining standards. The standard we are all intimately familiar with, American National Standards Institute (ANSI)/NSF 61, is being replaced by ANSI/NSF 600. This change goes into effect Jan. 1, 2023, and it will, almost certainly, have some effect on nearly all potable water linings installed in the United States.
The new standard has tighter limits for acceptable extractable levels in some compounds, and this will remove some potable water linings products from the market in general. However, there has been a lot of rumor, worry, and gossip that the entire industry will be forced to switch to waterborne or 100 percent solids, and this simply isn’t true.
Linings are being installed right now, and have been for some time, that are fully NSF 600-compliant. In preparation for 2023, NSF has released new requirements, and manufacturers have already begun getting various potable water linings tested for NSF 600 compliance. The new standard’s most significant change is a several orders of magnitude shift in the allowable extractable levels of aromatic solvent traces, which typically are associated with bulk xylene and similar solvents.
Naively, this may lead one to assume there will no longer be solvent-borne products available for potable water application. Yes, many applicators are using 100-percent solids, plural-applied epoxies on jobsites. But those same contractors were already doing that —
and have been for years. There are also NSF-600 complaint, solvent-borne, single-leg airless-applied epoxies that are still being sprayed.
Contractors that regularly install potable water tank linings should check with manufacturers and see if the products that are being regularly applied will be NSF 600-compliant. But from the jobsites I am seeing right now, I do not think the change from NSF 61 to 600 will be the industry-shattering change that some have made it out to be.
Typical Systems
The typical system I see installed on potable water tank interiors in the field during recent years looks like one of two of the following types:
1. Type A
• SSPC: The Society for Protective Coatings Surface Preparation (SP) 10 blast
• NSF 600-compliant, thin-film epoxy primer (roller or airless applied)
• NSF 600-compliant, 100-percent solids, thick-film epoxy (plural airless applied)
2. Type B
• SSPC SP-10 blast
• NSF 600-compliant, approximately 70-percent solids, thin-film self-priming epoxy (roller or airless applied)
• NSF 600-compliant, approximately 70-percent solids, thin-film self-priming epoxy (roller or airless applied)
Most contractors are already familiar with these sort of lining systems and have the equipment and skilled labor to handle them. The barrier to entry for executing potable water lining jobs isn’t going to change much at all. My recent experience tells me that an earth-shattering change to a new technology for NSF 600 compliance isn’t necessary.
With NSF 600-compliant, thin-film, solvent-borne epoxies on the table, I really have trouble conceptualizing how there would be a major industry shift to a different new resin technology or application style. As has been the case for several decades, contractors that need high throughput application and high production rate spraying will typically opt for something similar to the Type A system, as plural application has a higher cost barrier to entry. But ultimately, this can result in greatly reduced cure times and less time spent spraying. This cost analysis makes more sense as jobs get larger, typically speaking. Plural application makes a lot more sense for a 250,000-square-foot (23,225.8 m2) series of tank interiors than it does for one small municipal elevated water tank.
Likewise, contractors who preferred single-leg airless and roller application have always used the thin-film epoxy systems and will continue to do so under NSF 600. Some products are going away, yes, but not all of them. New products will come out to fill those gaps left behind. This has already happened, and it will continue to do so.
There is a major opportunity here for the industry to evaluate how it looks at immersion-grade primers, a product type that has historically been associated from a chemistry perspective with inherently high levels of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs). NSF 600 is already facilitating change there.
A Solved Problem?
Perhaps it is anticlimactic to write an article entitled “Notes from the Field” on NSF 600, only to tell the reader that they need not worry much about it at all. But my biggest takeaway from the field concerning NSF 600 is that it is already a solved problem, and it has been for quite some time.
As an industry, though, I believe we do need to take the time to ensure that all specifications and active jobsites — which we are in contact with as manufacturers, applicators, engineers, and owners — are updated to reflect the changes coming in 2023. That said, the necessary changes for all parties are likely to be simple, and they should not present as much hassle as some seem to believe.