How do fire alarms work?

  • July 28, 2021

You likely know that a fire alarm can save your life. But do you ever wonder just exactly how do fire alarms work? Why are they so effective? And what do I need to do to ensure they keep working?

The numbers, unfortunately, don’t lie. According to the National Fire Protection Association (NFPA), 41 percent of home fire deaths happened in homes with no smoke alarms, and the death rate is more than twice as high in homes without smoke alarms. 

Having a fire alarm system and understanding the ins and outs can keep you safe, and we break down the details why below. 

Choosing Your Fire Alarm

According to the NFPA, there are three standard fire alarms: ionization alarms, photoelectric alarms and combination alarms. When it comes to understanding how these fire alarms work, there are slightly different functionalities for each:

  • Ionization alarms: this type of alarm is most effective when flames are present. In an ionization alarm, a small amount of radioactive material flies between two electrically charged plates. This ‘ionizes’ the air and creates a current between the plates. When smoke enters the alarm, it disrupts the ions and activates the alarm. 
  • Photoelectric smoke alarms: this type of alarm is most effective for fires with a long ‘smoldering’ period. In a photoelectric alarm, the alarm casts a light into a sensing chamber, angled away from the sensor. When smoke enters the chamber, it reflects the light onto the light sensor, triggering the alarm. 
  • Combination alarms: this alarm combines both technologies and is considered one of the safest and most effective alarms available. 

So, which type of fire alarm should you choose? 

According to the NFPA, “for each type of smoke alarm, the advantage it provides may be critical to life safety in some fire situations. Home fatal fires, day or night, include a large number of smoldering fires and a large number of flaming fires. You cannot predict the type of fire you may have in your home or when it will occur. Any smoke alarm technology, to be acceptable, must perform acceptably for both types of fires to provide early warning of fire at all times of the day or night and whether you are asleep or awake.” 

As such, look for combination alarms for your property. 

Alarm Installation

Once you’ve chosen the appropriate fire alarm, the next step, installation, is critical. The way you install the fire alarm is essential to its efficacy. In other words, it could save your life. The NFPA recommends the following when installing your fire alarm:

  • Choose an alarm with a label from a recognized testing laboratory: these alarms are entirely up to code and offer the best protection. 
  • Install smoke alarms in each bedroom, outside each sleeping area, and on each floor of the home: this ensures that the fire alarm can identify and alert you to risk no matter where it occurs in your home. It’s imperative to have a fire alarm in your bedroom in the event of a fire at night. 
  • On levels without bedrooms, install the alarms in the living area or near the stairway to the upper level: the goal here is to give residents every possibility to hear the alarm. In addition, installing the alarms near living areas and stairwells increases safety. 
  • Install basement or subterranean smoke alarms on the ceiling at the bottom of the stairs leading to the next level: this increases the likelihood of escape in the event of a fire. 
  • Install smoke alarms at least 10 feet away from any cooking appliances: this reduces the risk of burned toast (or something similar) setting off a false alarm. 
  • Keep smoke alarms high on the walls or ceiling: smoke rises, and the alarms are more likely to identify a risk quickly if they’re high on the walls. 

If this process sounds complex or overwhelming, don’t worry. You can always advise or hire experts for fire alarm installation

Alarm Maintenance

Smoke and fire alarms shouldn’t be installed and forgotten about; they require a bit of maintenance. The NFPA recommends following the manufacturers’ instructions for your specific fire alarm, along with the following maintenance tips: 

  • Test smoke alarms at least once a month.
  • Ensure that everyone in the house/business understands the sound of the smoke alarm, what it means and the appropriate response. (You could even stage a fire drill, if necessary).
  • Follow manufacturer instructions to keep the alarms working well.
  • Replace batteries regularly, when applicable, especially if you hear a chirping sound.

Invest in Your Fire Safety 

When it comes to figuring out how smoke alarms work, it’s important to know the basics and reach out for help if you need it. Whether it’s for your home or business, a properly functioning fire alarm system is a must. While it may represent an upfront investment as far as equipment purchase and installation, it’s an expense that can save lives.

At A&A Fire Protection, we’d be delighted to help. For more information or to schedule an appointment, get in touch today

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