Revise the state building code to allow single stairwells in certain buildings

This bill amends Montana's state building code to allow certain residential buildings to have a single stairwell instead of requiring two separate exits. It specifically permits Group R-2 occupancy buildings with six stories or fewer and no more than four units per floor to use one stairwell if they have an automatic sprinkler system and each unit has an emergency window or exit. The legislation also grants the state department rulemaking authority to adopt these changes while maintaining existing safety standards for fire protection and emergency egress.