The Windgap Bridge in Pittsburgh, Penn. was painted in 1986 with Tnemec polyurethane coatings. While the original specification called for a phenolic zinc-rich primer, Tnemec’s local coating consultant spoke with the contractor and engineer about a new Tnemec moisture-cured, zinc-rich urethane, Series 90-97 Tneme-Zinc. Benefits of Series 90-97 included superior corrosion resistance, a more user-friendly application and better curing tolerance at lower temperatures. All parties agreed to the change, and one of the first Series 90-97 projects was under way.

The photographs to the left were taken in 2007. After 20 years of service, the Tneme-Zinc/epoxy/polyurethane system is still performing extremely well. Note the gloss of the 20-year-old Endura-Shield finish coat.

The bottom photo shows the signs of an inspection that occurred in 1989. Note the reddish-gray Series 90-97 that was left un-topcoated for 18 years. No corrosion has occurred other than where Series 90-97 was scratched away during destructive cross-hatch or Tooke gauge inspections. The confined rusting and lack of undercutting are a testament to the galvanic protection capabilities of Series 90-97 Tneme-Zinc.

Reports from a 2007 professional inspection indicate that many more years of service life can be expected.