The Louisiana State Fire Marshal’s Office has issued guidelines for installing locks on the inside of classroom doors to help secure campuses during an active shooter situation.

Chief H. “Butch” Browning outlined the new guidelines in a pair of memos issued this month to all schools and daycare facilities in Louisiana, reported

The proposed door locks will serve as a secondary line of defense after security measures like fences, metal detectors, and security guards, which are meant to control access to the campus, said the report.

Schools will be allowed to install one single cylinder deadbolt lock with a thumb turn on the classroom side of each classroom door between 34 inches and 48 inches above the floor, according to the report.

A sign reading “Lock is for teacher’s use only” will be installed next to each door, and all door locks on campus will be opened with the same key, which “responsible school staff shall have available at all times.”

A reliable two-way communication system between the locked classrooms and the front office is recommended, and procedures will be instituted that clearly distinguish between a signal for an evacuation for a fire or other emergency and a signal for a shelter-in-place emergency, according to the memo.

The guidelines do not apply to large rooms with an occupancy of 50 people or more.