What I Learnt About Fire Alarm Systems

Kumar Gauraw

A few weeks ago, one of my friends came with his family to visit us over a weekend from Irving,TX. They stayed overnight with us and we had a great time cooking, watching movies and just talking about various things.

House On Fire - Firemen Working

As they returned to their apartment community the next day, they discovered that there had been a fire in their neighborhood during that night and two or three buildings around their building had turned into ashes. They just got lucky as their building was still standing and so their belongings were safe.

I had never paid much attention to house fire situations before (I just never had any interest in the subject). But that incident got me curious about the causes of house fire, the fire alarm systems and the process around fire prevention. So, I decided to share a few things I have recently learnt about fire alarm systems with you today.

By the way, I have a continued love-hate relationship with smoke detectors (a type of fire alarm systems) since I first got introduced to them. My tussle with smoke detectors started the day I came to the United States several years ago and when it started to buzz whenver I entered kitchen. 

The smoke detectors don't seem to like the way we cook our Indian food. Our cooking method simply produces smoke sometimes and as soon as that happens, the smoke detector goes off scaring my boys instantly.

And to add to the trouble, during my stay in Frisco, our smoke detectors would go off all by themselves at midnight (sometimes at 2 or 3 AM) while everybody is asleep, play for about 15-20 seconds and then stop automatically. That went on for several weeks arbitarily with no idea why it was happening. Later, we figured there was some kind of mechanical fault in the fire alarm system.

Yet as I study more, I still think it’s a good thing to have in the home. In spite of all the heartache I have had with it, I still think that it simply can be a life saver. Therefore, I invested a good portion of time in recent weeks to learn about fire alarm systems, their types and their functionality.

And now, let me share with you what I found out about the fire alarm systems and how they function:

Types Of Fire Alarm Systems

Depending on the need and the place, there are different types of fire alarm systems that can be installed. Here are some of the most common type of the detectors:

Heat Detectors

As the name suggests, these detectors are the type of fire alarm systems that are best suited for environments where a fire is likely to produce heat and very thick smoke. These type of detectors have two temperature-sensitive elements known as thermistors. One thermistor is in contact with the surrounding air while the other is enclosed.

When the air temperature rises above a certain threshold, the exposed thermistor's resistance to electric current decreases. That allows electric current to flow through the thermistor and sound the alarm.

Photoelectric Smoke Detectors

Photoelectric light smoke detectors employ a light source and a light sensitive device. When smoke particles block the light beam, the light sensitive device identifies the reduction in light and it modifies its output. The change in output is sensed by the detector’s circuitry and when the pre-set threshold is passed, the detector sounds the alarm.

Photoelectric detectors are a type of fire alarm systems that are most effective for fires that generate visible smoke. These are one of the popular smoke detectors used in homes in the US.

Ionization Smoke Detectors

This is the detector  that is notorious for giving false alarms. A typical ionization smoke detector typically consists of two plates in close proximity to each other and a radioactive source (typically, this consists of a very small quantity of radioactive element Americium-241). Both plates are connected with a battery, which applies voltage to the plates.

When smoke enters this chamber, it interacts with the ions so the current ceases to flow. A microchip registers the drop in current and sounds an alarm. These kinds of systems are very effective at detecting small smoke particles including the ones that are so small that they may even be invisible. But are these detectors are not very effective at sensing dense smoke.

These smoke detectors are popular as well and many experts recommend to use these detectors along with the photoelectric detectors for safely being able to detect any kind of fire threat.

Resources For More Information

Here are a few useful links to some resourceful websites where you can get more information about such systems:

Questions: What type of fire alarm system do you use in your home? What type of fire alarm system do you recommend? Please share your knowledge in the comments by clicking here.

Thank you kindly!

Kumar Gauraw

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Kumar Gauraw is a Personal Branding & Social Media strategist helping entrepreneurs and skilled professionals achieve personal and professional success by developing leadership and leveraging the power of the Internet, Blogging and Social Media.

14 Awesome Thoughts So Far, Add Yours Now...

  1. Ramesh

    It is very interesting post sir. In India, we don’t use any fire alarm as our houses are not built of wood. I think people in US and UK need it more because of their wooden houses. Good info.

    • Yes Ramesh. It is very much a need in US and UK as you mentioned because of the way houses are built here. Thanks for dropping by.

  2. Great Details Mr. kumar. This page is a great cheat sheet to have details about Fire Alarm in our house.Sometime it might save the big fire accident. Again thanks for sharing:).

  3. Hi Kumar,

    A few days ago we watched a Dateline story on NBC about the failure of many ionized smoke alarms to sound. In cases cited, dense smoke had already filled the area and the alarm did not go off until well after 30 minutes.

    One lady lost her 4 children because of it. The show related that the photoelectric smoke detectors were slightly better. The one they showed went off after about 15 minutes.

    What is important to note are the safety measures that each family should take in the event of a fire. Notably:

    ~ Install detectors on every level of your home.
    ~ Test and replace the batteries twice per year.
    ~ Plan and practice an ESCAPE ROUTE with your family twice annually.
    ~ Parents with children should decide ahead of time what child or children each of them will be assigned to wake up and lead to safety.

    I think it’s also wise to have a reliable fire extinguisher in your home in a convenient place. Many insurance companies offer a reduced rate on insurance just for having one.

    Kind Regards,

    • Bill,

      Sad to learn about the lady who lost her children because of the failure of the smoke detectors. It is such an unfortunate thing.

      Well, and your comment just added another reason why we should be using smoke detectors in spite of the falst alarms I keep getting sometimes.

      Thank you for your value addition through this story. Appreciate you taking time to share.



  4. About six months ago, we found out that an entire apartment complex had fake fire alarms. The renters there figured it out when an accidentally left something in the oven and the smoke filled the room… however no alarm went off. They checked the fire alarm only to find there was nothing underneath what looked to be a plastic casing, except to a tiny battery and it flashing red light to make it appear that it was on! Crazy!

  5. Thanks for sharing, great article!Photoelectric Smoke Detectors are very effective.

  6. Good to know about the fire alarm systems, have bought as new house and am planning to install a really good system. Thanks a lot for your post it really helped.

  7. It is an interesting post that you have shared with us. Fire alarm system is a good idea to be safe during house fire. Thanks for sharing this.

  8. It is a great thing that we know something about fire alarm. This is indeed helpful to all people who would like to install some home fire alarms and yet don’t know what kind of alarm is best for their homes. It is also important that you know everything about that alarm system before you install it in your homes. Thanks for sharing!.

  9. Excellent article, Kumar. Reliable smoke detectors and fire extinguishers are certainly essential for fire safety.
    In addition applying non-toxic flame retardants can make a huge difference when escaping a fire by prolonging the time for escape.

  10. So sad to hear about your friend’s house appalling situation. That’s why I never hesitated installing an alarm system at home. I ensure that the system has fire detector aside from the burglary monitoring. We should always pay focus attention to our properties for what we could do to keep it safe before we leave, otherwise, we end up realizing that everything we invested by our hard-earned money just turned into ash.

  11. Very nice and informative article. Let me explain you brief about what type of fire alarms we should consider for our home. When deciding which type of alarm to buy you should consider which type of fire is most likely to occur in your home. Generally, both types of fire are common so the best form of protection would be to choose at least one smoke alarm of each type. Ideally, and to ensure continuity of supply, mains powered alarms with a back up power supply (e.g. battery, rechargeable capacitor) are the best option but simple battery powered alarms of either type will give good minimum protection.

Please Note: My goal is to host interesting conversations with caring, honest, and respectful people. Therefore, I reserve the right to delete comments that are snarky, offensive, or off-topic.