The city of Portland is appealing after a state agency demanded it rescind a city rule that requires large nightclubs to have automatic fire sprinklers.

The state Building Codes Division told the city in a letter last month it plans to fine Portland at least $20,000. The agency says cities can't enact rules that have different requirements than the state building code.

Fire Commissioner Dan Saltzman introduced the rule in 2013 requiring nightclubs that hold 100 people or more have automatic sprinklers. The state rule exempts existing buildings from having to add sprinklers as long as the building met codes when it was built.

"This is a clear example . . . of a state agency overstepping its bounds and overstepping it in the wrong direction," Saltzman told The Oregonian. The state, he said, is "reverting back to an old standard, which could result in a tragedy none of us want to see."