Allow me to further complicate and possibly confuse the issue by advising that among the substrate preparation choices, more (choices) is not necessarily better. If zinc primer is applied, is the primer organic or inorganic chemistry. If the items are fresh applied hot-dipped galvanized, were passivation or phosphate treatments added after galvanization? By way of example, if your supplier is applying polyurethane directly to recently galvanized (>6 months of weathering exposure) short-term coating adhesion failure should be anticipated. If the galvanized surfaces are weathered to naturally form zinc carbonates at the surface, passivated with chromate treatment, phosphated, or even abrasive blasted for surface profile, coating adhesion will be greatly improved. I suggest your specification permit some or all of these options with the requirement to identify which surface treatment process was used.
Original Message:
Sent: 12-03-2024 06:50 AM
From: Daniel Miller
Subject: Comparison of Paint Vs. Zinc Coated Vs. Galvanized Coatings for Natural Gas Meter Sets
David,
Appreciate the follow up. With regards to our current vendors, I'm assuming if we talk to each of them they are going to say they are using the best product on the market. What we are looking for is a truly independent comparison of zinc vs. galvanized vs. urethane coated parts exposed to typical outdoor environments. There are a lot of gas pipeline operators that are AMPP members so I'm hoping to hear back from someone in our field?
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Daniel Miller
MidAmerican Energy Company
Sioux City IA
+17122777933
Original Message:
Sent: 12-02-2024 07:10 AM
From: David Fernee
Subject: Comparison of Paint Vs. Zinc Coated Vs. Galvanized Coatings for Natural Gas Meter Sets
Dear Dan
-
To follow up on Brent's comment, the "mixed bag of coatings", I would also suggest that you contact the vendor/applicator of the coatings to discuss the field failures. In advance of that meeting, I would also recommend that you request the Product Data Sheets for each of the products applied.
From there you can discuss other products that will meet your performance requirements.
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David Fernee
Sherwin-Williams Co.
Warrensville Heights OH
+12163321161
Original Message:
Sent: 11-21-2024 06:52 AM
From: Daniel Miller
Subject: Comparison of Paint Vs. Zinc Coated Vs. Galvanized Coatings for Natural Gas Meter Sets
Brent, thanks so much for the reply. To clarify, when our field folks install our gas meter sets, the coating has already been applied by the vendor. Everything is essentially assembled in the field. My concern is that some parts are simply painted with polyurethane from the factory, some have a thin zinc coating, and some are fully galvanized. We are trying to choose the best coating system and require ALL gas meter set parts to have the same coating. We just don't understand the benefits of one coating system vs. another. Thank you!
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Daniel Miller
MidAmerican Energy Company
Sioux City IA
+17122777933
Original Message:
Sent: 11-19-2024 10:10 AM
From: Brent Bergman
Subject: Comparison of Paint Vs. Zinc Coated Vs. Galvanized Coatings for Natural Gas Meter Sets
Hi Dan!
The "mixed bag of coatings" may not be the cause of protective coating failures. I suggest you look into the surfaces under the coatings to identify the failure sources. Failures between the substrate and the first coating layer are typically the results of contaminated surface and/or inadequate surface preparation. Oil/grease residue from other work activities are a frequent problem along with salt (chloride, nitrate, sulfate) contamination and these contaminants can exist on any substrate and will cause failure regardless of the coating type. The surface can't be too clean.
Adequate surface preparation by hand or power tool cleaning and pressure washing will provide a surface that appears clean and roughened but may not remove invisible contaminants or provide enough surface for the coating system to be used. Instructions like "roughen the surface by hand sanding..." mean different results from each project. Check with the coating manufacturer for surface profile requirements and the methods to achieve the requirements.
Service conditions the coating will be exposed to can be challenging. Weather, chemical exposure, and stray currents will all shorten the life of any coating system.
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Brent Bergman
Dominguez Hills CA
+15628899451
Original Message:
Sent: 11-15-2024 07:15 AM
From: Daniel Miller
Subject: Comparison of Paint Vs. Zinc Coated Vs. Galvanized Coatings for Natural Gas Meter Sets
Hello all, my name is Dan Miller. I am new to this technical community. I am the Principal Engineer here at MidAmerican Energy Company, and I manage our DIMP program. We are having a lot of issues in the field with our leak surveyors not turning in early signs of corrosion on our meter sets. One thing that has become obvious to us is that we have a mixed bag of coatings that are being installed in the field. Some, especially the polyurethane-coated parts, are not holding up well. Can anyone point me to a technical paper that compares these basic coatings types for natural gas use? I'm assuming we want to go the galvanized route, but would like some documentation to prove that. Any ideas would be greatly appreciated!
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Daniel Miller
MidAmerican Energy Company
Sioux City IA
+17122777933
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