Fires in one unit of a multi-family dwelling can quickly spread to other units.

Smoke Detector Requirements in Multi-Family Structures

by Tara West

The Federal Emergency Management Agency states that when working smoke alarms are present, the chance of dying from the fire is cut in half. This makes properly installed and functioning smoke detectors vital for any home. Multi-family structures are unique in that a fire in one unit can quickly spread to another. This means, special precautions and recommendations are made for these types of dwellings.

Types of Smoke Detectors

According to FEMA, twenty-seven percent of non-confined multifamily residential building fires extend beyond the room of origin, with an estimated 108,400 multifamily residential building fires in the U.S. per year. This makes multifamily dwellings smoke detector needs slightly different than for a single family dwelling. The smoke alarms should be interconnected, which means that the activation of one alarm will activate all of the alarms in the unit. If a fire is in a hallway outside of a unit, it should activate alarms in all units in the structure. Multi-family structures may also consider interconnected fire alarms between all units; meaning, if an alarm is activated anywhere in the building, the alarms in every unit are initiated. Since fires can spread quickly between multi-family structures, this is recommended by FEMA.

Quantity Needed

FEMA points out that many homes do not have as many smoke alarms as are needed to protect the occupants properly. Therefore, it is important to properly install smoke alarms in the correct locations and in correct quantity. In multi-level units, a smoke detector should be located on each floor. Any room that frequently has it's door shut should also have a smoke alarm. For example, if you sleep with your bedroom door shut, the room needs it's own smoke detector.


Smoke alarms should be installed on the ceiling or at the top of the wall. If installed on the wall, they should be between 4 and 12 inches from the ceiling. Installation of an Automatic Extinguishing System is also suggested by FEMA for multi-family structures. An AES would include sprinkler systems or other distinguishing devices mounted in the ceiling. Proper installation is key to a functioning system. Hiring a professional installation team can ensure that the alarm system is installed properly. When fire alarms were present in multi-family structures, only 35 percent operated correctly. The other 65 percent either did not function correctly or status was unknown, making proper installation all the more important.


FEMA estimated that a third of the smoke alarms in place are not working, often due to failure to replace a worn out battery. For multi-family dwellings, many states require emergency back-up batteries to be present and for the system to be installed electrically. This means the fire detectors are hardwired to the electrical system instead of with the use of batteries. This helps prevent battery replacement errors. Even with electrically mounted devices, alarms should be checked on a monthly basis.


The amount of fire detectors needed for multi-family dwellings varies from state to state. Each state has a different set of guidelines that must be followed. The guidelines can be found online at each state website or by contacting the state Fire Marshall.

About the Author

Tara West graduated from the University of Tulsa with a bachelor's degree in business administration and human resources. West specializes in parenting, green living and career development as a regular contributor at She has been featured on a variety of websites including a childhood favorite, Reading Rainbow.

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