Tie treatment options offer sustainability, safety, fire retardancy

By Michael Popke

As wood-tie manufacturers aim to increase production capacity and efficiencies, tie treatment companies also are seeking ways to step up their respective games.

For example, Nisus Corp. offers the BTX System, which is designed to treat large bridge ties with a combination of QNAP® copper naphthenate and Cellu-Treat® borate. The process places the liquid borate directly into the center of the timber via a BTX plug. During the Boulton cycle, the borate is drawn from the ports and travels through the heartwood of the tie. Then the bridge ties are pressure-treated with QNAP.

A U.S. Environmental Protection Agency-registered preservative, QNAP is created from recycled copper and by-products of oil refining, making it “green from the start,” the company says. Copper naphthenate is not a restricted-use preservative — the amount of copper in the preservative can be increased without also boosting the amount of preservative pressed into the tie during pressure treatment, says Nisus President and Chief Executive Officer Kevin Kirkland.

“This means less drippage, which is critical on bridges over roadways and rivers,” he says. “From a safety standpoint, railroads are impressed with the cleaner handling characteristics and the fact that these ties are significantly less slippery when wet — also important on bridges.”

There also have been developments in the fire-retardant realm. An arm of Arch Wood Protection Inc. — Lonza — has teamed with FPInnovations in Canada to market FireSheath™, a fire-retardant coating for wood railroad bridges, crossties and utility poles. The company’s WFS Net™ is an intumescent coated mesh designed to protect wood in case of fire by forming a protection barrier that stops the spread of flames. The product is the first one to fully stop creosote from burning, says Arch Wood Product Manager Tim Carey.

During testing, ties wrapped in FireSheath WFS Net and unprotected ties were engulfed in flames; the wrapped ties did not burn, says Carey, adding that CN has expressed interest in the product.

Michael Popke is a Madison, Wisconsin-based freelance writer. Email comments or questions to prograil@tradepress.com.