City of St. Paul Park 

on the Mississippi

Smoke Alarms 101: A Short Course in Safety

Roughly 80 percent of fire deaths in the U.S. take place in homes without working smoke alarms. In fact, half of home fire deaths occur in the six percent of homes with no smoke alarms at all.


Using smoke alarms is a matter of personal safety and common sense. It’s also a matter of compliance with Minnesota law. Every home in our state is required to have at least one smoke alarm per level. In new construction, a smoke alarm must be installed in each sleeping room and in a point centrally located in the corridor. These alarms must be interconnected.


In order to create a safe and legal home environment, you should start by assessing your living arrangement and determining the best type of protection for your home.


All smoke alarms consist of two basic parts: a sensor to sense the smoke and a very loud electronic horn to awaken and alert people. The two most common types of smoke detectors used today are photoelectric detectors and ionization detectors.


Ionization Alarms

An ionization smoke alarm uses a harmless radioactive source that sets up an electric current in the detector chamber. When smoke enters the chamber; the unit senses the change in electric current and sets off the alarm. Studies have shown that ionization detectors are better at detecting small, invisible particles that are typically present in hot, fast-burning fires such as grease or flammable-liquid fires.


Photoelectric Alarms

Photoelectric alarms sound when the smoke is dense enough to deflect a beam of light.  Photoelectric detectors are better at detecting larger, visible smoke particles more commonly produced by slow, smoldering fires such as couch or bedding fires.


Both types of smoke alarms have been proven effective in detecting typical residential-type fires. In cases where smoke detectors are subject to frequent false alarming due to cooking, smoking or similar causes, the State Fire Marshal encourages the installation of photoelectric smoke detectors as they are not as susceptible to false activation.


Battery powered

A battery-powered alarm is a basic smoke alarm with a hinged-cover that opens for easy battery replacement without removing the unit from the ceiling. Many features available, including an “escape light” to illuminate a path to safety when the alarm sounds. A Silence/Test button tests alarm functions and silences nuisance alarms.



AC powered

This AC powered (hardwired) smoke alarm has a Test/Reset button that tests the alarm and resets the memory. It may have inter-connect abilities and other features.


AC powered with battery back up

A120-Volt, AC powered smoke alarm with battery back-up for single- or multiple-station use may include a false alarm control feature that allows the user to quiet an unwanted alarm for up to 15 minutes.


Dual sensor

This alarm detects both smoldering and fast-flaming fires. Some have extra features including a remote-control to test or silence the unit without getting on a ladder or chair.


Voice Smoke & CO

A step forward from early combination CO and smoke detectors, this unit eliminates the need to decipher color codes. A voice alarm tells you the location of the unit and whether you’re dealing with smoke or CO.


Wireless Interconnect

These smoke alarms enable families to quickly and easily install an interconnected smoke alarm system throughout their home without any messy wiring or labor. The battery-powered units are linked so that when one alarm sounds, it will trigger all to sound. In addition to providing protection to any room in your home, the wireless smoke alarm also can be placed in a detached workshop or shed and linked into the home’s system.


Voice Programmable

This innovative smoke detector allows you to record escape instructions in your own voice. In case of a fire, this alarm will alternately sound a warning tone and play your message to help guide children to safety.


Hearing Impaired Smoke Alarm

If you, or someone in your home, is hearing impaired, your home should he equipped with smoke alarms that have a flashing light powerful enough to wake up a sleeper who may not hear an audible alarm, although an 85-decibel alarm is also included. Some models also include vibrating devices for extra warning.


Fire Chief Kurk Lee says, “Keeping a family and home safe from fire is the responsibility of everyone in the home.’’ The St. Paul Park Fire Department asks you to sit down together and discuss these important tips, equip your home with the proper alarms, and prepare and practice a fire escape plan. Should you have any questions please feel free to call us at (651) 459-9918.

City of St. Paul Park, 600 Portland Avenue, St. Paul Park MN 55071