Minnesota builders no longer have to install sprinkler systems in large new homes, after they won their legal battle against the year-old fire safety requirement in the state building code.

The Minnesota Supreme Court this week declined to hear an appeal of an October court ruling that invalidated the rule. Homebuilders complain that the sprinkler systems are expensive and say there’s no evidence to support claims that they save lives in newer homes.

“It’s really a victory for homeowners and for the affordability of homes,” said Shawn Nelson, past president of the Builders Association of the Twin Cities, which challenged the code. “The data pretty clearly shows that to the extent that there’s a fire safety issue, it’s in existing homes, and we think there are reasonable affordable ways to solve the issue that we should be focused on.”

But firefighters say mandatory sprinkler installation is the only way to reduce the 3,000 deaths nationally from fires each year.

“It just puzzles us in the fire service why the homebuilders wouldn’t want to sell to their customers a safe product,” said St. Paul Fire Marshal Steve Zaccard. “You can’t buy a car without seat belts and now you can’t buy a car without a backup camera.”

The fight between builders and firefighters over sprinkler requirements in Minnesota has played out in all three branches of government.

The Legislature passed bans on any sprinkler mandate in 2011 and 2012, but Gov. Mark Dayton vetoed them each time. In 2014, legislators tried to get the ban into a $1 billion capital investment package, only to back off after another veto threat from Dayton.

Since then, the state Department of Labor and Industry, which is responsible for the Minnesota State Building Code, adopted a code effective last January that required sprinklers only in new homes larger than 4,500 square feet.

Firefighters have advocated for sprinklers to be required in all new homes, but agreed to the compromise with the hope that smaller homes would eventually be phased in.

But the Builders Association of the Twin Cities sued to stop the rule and prevailed in the Minnesota Court of Appeals, which ruled that requiring sprinklers in homes that are 4,500 square feet and larger was arbitrary.

“Provisions of the Building Code must be based on the application of scientific principles, approved tests and professional judgment, and there is simply no evidence or explantation to support the determination that new two-family dwellings and new one-family dwellings over 4,500 square feet present a fire-safety risk that justifies the increased costs of sprinkler installations, while new one-family dwellings under 4,500 square feet do not,” Judge Francis Connolly wrote.

Although the International Building Code — a model code adopted in most of the country — currently calls for sprinkler systems in all new homes, Nelson said that more than 40 states removed the provision for their codes because there’s no safety data to justify the cost.

For the year the code was in effect, Nelson said some Minnesota builders were required to install sprinkler systems, and others lost contracts because homeowners did not want sprinkler systems. Builders want to work with firefighters on other fire-prevention methods, such as wireless interconnected smoke detectors in existing and older homes, he added.

“Honestly, our hope is that we’re able to work with the fire services and Legislature where we’ve had bipartisan support to look at data and facts and come up with reasonable and common-sense solutions that don’t put such an expensive burden on homeowners,” he said.

In the meantime, firefighters are regrouping.

“I don’t know what our next step will be,” Zaccard said. “We’ve got to better educate the public about the value of sprinklers.”