Fire alarms in business occupancies (Group B) provide early detection and notification to quickly evacuate occupants when businesses are open. The alarms also can  alert emergency services during closed hours, which can reduce property damage and inventory loss. The number of occupants and their ability to evacuate are the two main determining factors in deciding whether or not a fire alarm is required in a business occupancy. The 2020 edition of the Minnesota State Fire Code (MSFC) and adopted 2016 edition of NFPA 72 provide detailed requirements for the selection and installation of the initiating devices and notification appliances throughout the entire business occupancy. 

A fire alarm is required in a business occupancy when:

• The building has an occupant load of 500 or more people.
• The building has an occupant load of 100 or more people above or below the lowest level of exit discharge.
• The building contains an ambulatory care facility.

In other than ambulatory care facilities, a fire alarm system is not required when an approved automatic sprinkler system is installed throughout the building.