Who is the biggest floor-cleaning equipment maker in town?

Who's the big global manufacturer of floor-cleaning equipment located in the western suburbs?

Golden Valley-based Tennant Co., right? The cornerstone Minnesota company is headed toward sales of $755 million this year, according to analysts.

Then there's low-profile neighbor Nilfisk-Advance in Plymouth, the U.S. headquarters of the Danish manufacturer that's expected to post sales of about $1.2 billion this year.

Nilfisk-Advance concedes that it controls only about 9 percent of the U.S. cleaning-equipment market compared with an estimated 13 percent for Tennant — the U.S. market leader. But Nilfisk-Advance says it has started to grow market share in the United States, its single largest market.

"Our flagship industrial products are built in Plymouth, Minnesota," said Jeff Barna, who took over as president in 2012 of Nilfisk-Advance's U.S. business, which has 600 employees and is growing.

The relationship between the neighboring competitors has been contentious in recent years, with Nilfisk calling out Tennant on some of its advertising claims.

Barna, who took over in 2012, wasn't president when the advertising claim was lodged a couple of years ago. He declined to comment on that flap but said generally about Nilfisk-Advance's performance over the past year: "This company is stepping it up. We've got the great people and assets to win on a continuous basis."

Barna, 52, is a veteran sales and marketing executive who last worked at Exide Technologies, the battery manufacturer that filed bankruptcy in June. Barna succeeded a Danish engineer who was considered more focused on technology and operations than sales in a slow-growth industry hobbled by federal government spending cuts and flat education spending — two of the competitors' biggest markets.

Nilfisk-Advance is growing more than two times faster in the U.S. than the company's global 2 percent rate of growth through the first half of this year, Barna said. Tennant's sales were up more than 5 percent in the third quarter and about 1 percent year-to-date. Nilfisk-Advance, part of Denmark's NKT, will report its third-quarter results later this month.

Barna's assessment of Nilfisk-Advance when he arrived 15 months ago "was along the lines of us being a company that consistently demonstrated an ability to not live up to our potential. We're now unleashing the potential of shared leadership. Our third-quarter results will be awesome. Our business results are following the cultural upgrade around here."

Nilfisk-Advance makes and sells equipment nationally under the brands Advance, Nilfisk, Clarke, Viper and others.

Mike Tanner, CEO of Salt Lake City-based Bell Janitorial Equipment, a Nilfisk distributor of Clarke equipment for schools, offices and factories, confirmed there's been change at Nilfisk.

"Barna called me one night about 7 p.m. after he took over and asked about any problems and said we're going to make things go better," Tanner said. "I was impressed that the president sought out a scrubber dealer in Salt Lake. They make a nice, feature-rich piece of equipment that is durable and does the job."

Even before Barna took over, Nilfisk started attacking Tennant.

Over the past seven years, Tennant's chemical-free cleaning technology has been the major growth engine for the Golden Valley-based company. Since 2010, Nilfisk-Advance has argued that Tennant's marketing claims for the eco-friendly products aren't legit, stirring up a dust storm between the floor cleaners.

Responding to a complaint from Nilfisk, an arm of the Better Business Bureau examined Tennant's marketing claims for its technology, which electronically converts tap water to activated water to clean without chemicals.

The council of the Better Business Bureau's National Advertising Division (NAD) concluded that Tennant had overstated the new products' cost savings and should stop asserting that it delivers a "superior" cleaning performance.

Nilfisk contacted media outlets and issued a news release proclaiming it had unmasked Tennant.

Nilfisk announced that Tennant's activated water cleaned no better than plain tap water. But Nilfisk got its hands slapped on that one for violating an NAD rule that prohibits companies involved in the ad group's proceedings from using rulings for promotional purposes.

In a separate spat this fall, Tennant withdrew an appeal of a German court ruling over allegedly misleading ads about its hot-selling, chemical-free floor cleaners. The withdrawal let stand a June 2013 decision in favor of competitor Alfred Karcher GmbH & Co. The German court ordered Tennant to change the language of its ads. Tennant maintained the German court erred.

"In September, we announced our decision to channel our resources into new product innovations, and we withdrew our appeal" concerning Tennant's ec-H2O chemical-free cleanser," Tennant spokeswoman Kathryn Lovik said in a statement. "This technology is based on the established science of electrolysis."

She added that Tennant is introducing new technologies and products at a "robust" pace.

About direct competition with Nilfisk-Advance, Lovik said: "To the extent that Nilfisk sells cleaning equipment, they are a competitor to Tennant Company but not in the area of sustainable cleaning technologies."

Nilfisk begs to differ.

On a recent tour of the huge plant in Plymouth, officials talked about their new "green" class of hybrid-powered industrial sweeper-scrubbers that use half the fuel and increase battery life for several types of machines.

Also, the company says its "ecoflex" technology allows machine operators to switch between water-only and various-level detergent modes as required by the job. It uses up to 70 percent less water.

"We line up well with our products," Barna said. "The recent results give us confidence that our way can work."

Neal St. Anthony • 612-673-7144