Smoke Detectors in Security Systems

Smoke Detector
Smoke Detector

Smoke detectors are fire indicators that automatically detect smoke and notify about it to the respective departments. These notifications could be visual or audible warnings. At times, these warnings are produced at the location where indicator itself is installed and hence, these detectors are also referred to as “alarms” in such cases.

These detectors are an amazing invention that saves hundreds and thousands of lives all around the world each year. And, these small gadgets don’t even break you and are economically priced due to their mass production. You can get your hands-on one by paying as low as $6 to $7.

You would be amazed to know that these fire alarms (smoke detectors) are compatible with surveillance and security systems as well. Thus, these days security lovers are able to connect the wired smoke detectors to their existing security camera systems. And, here are all the reasons for the question “Why would you do so?”

  1. If there is fire on one floor, a dedicated security system configured with an alarm can easily alert people in the whole building.
  2. A smoke alarm, when connected to an HD security system that is configured to dial concerned departments in case of emergency, will act as a great savior in case of fire emergency. If fire breaks out, your security system will automatically dial the number of the fire department and alert them.
  3. Conventionally, the owner has to keep a regular watch on the battery of their fire indicators as they don’t last forever. When consolidated with security systems, this daunting task won’t double up as you might be expecting (changing batteries of fire detector as well as the security system) because just one battery can power both, the detectors and the HD surveillance cameras.
  4. A smoke indicator and security system combo can also help you save pets along with saving humans. The video operator can look up the concerned areas and send immediate help.

Now, you’d be wondering what actually is inside that little detector which makes it so powerful that it saves a life. So, let’s just explore it a little more:

How do smoke detectors work?

There are two different answers to the question depending on which detector (indicator) we are talking about. Basically, there are two kinds of indicators – optical or photoelectric smoke detectors and ionization smoke detectors. The optical or photoelectric indicators can be perceived as an electronic eye while the other ones can rather be considered as electronic nose. This perception can best be understood with the explanation given below.

Optical (Photoelectric) Smoke Detectors

These detectors are capable of detecting the hot gases and particles generated by fire. The hot gases are thinner and less dense in contrast to ordinary air and immediately rise upwards toward the ceiling. Small smoke particles that swirl along with these gases also head in the upward direction. For this reason, optical detectors are most generally fitted on the ceiling itself.

The photocell indicators are built with a large opening at the bottom, followed by a detection chamber up above. A source of ultraviolet, infrared or visible light shoots the beam through the chamber. This source is usually a light-emitting diode (LED) or an incandescent light bulb. This beam is focused on a detector and forms a kind of light circuit.

As long as there is no fire, this light beam unceasingly shoots on the detector. The electronic circuit affirms that everything is working fine and the alarm is quiet. However, in case of fire, the smoke particles interrupt the light beam and the current in the electronic circuit ceases to flow.  The electronic circuit spots this change, detecting that something is wrong and immediately sets that booming alarm to save many lives.

Ionization Smoke Detectors

Detectors that belong to this category are an economical option and work in an entirely different manner. Referred to as electronic noses, these devices use some kind of chemistry to detect the unusual particles entering into the circuit just like the nose in front of your face does.

Ionization smoke indicators contain a chamber which contains a radioactive element, most commonly, americium. This radioactive substance continually emits small particles known as alpha particles in the area across the detection chamber. Further, these alpha particles collide with air molecules of detection chamber and convert them into ions (positively charged) and electrons (negatively charged). The detection chamber also contains two electrodes which act just like the terminals of a battery. The positively charged ions and negatively charged electrons get drifted towards the oppositely charged electrodes. As long as there is no fire around, the ions and electrons keep moving conventionally, thus, there is a continuous current flowing through the circuit. This flow of current is monitored by an electronic circuit inside the detection chamber.

When the smoke particles enter the chamber, the ions get more attracted to it rather than moving towards the electrodes. All this clogs the detection chamber and shuts off the current, which is straight away detected by the electronic circuitry. The deafening alarm is set on to intimate the nearby people about the fire. Once the fire comes under control and all the particles clear up, the electric current starts flowing again and it automatically shut off the nasty alarm.

Which one is better – Photoelectric or Ionization?

Photoelectric detectors offer a better response to flaming fire situations and photoelectric detectors provide a better response to smoldering fires.  Whatever type you pick up, it is always better than having no indicators at all. If possible, try to incorporate both types of alarms in your surveillance systems.

What are the best options for placing smoke detectors?

The best bet for the placement of a fire indicator is having one on each floor of the building. It is preferable to place them on the ceiling or else, high up on the wall. Avoid placing them near the juncture of the walls/ceiling as these are considered to be dead air areas. Also, avoid areas where the density of particulate matter like dust and exhaust is high such as in attics and garages.

These indicators, when consolidated with your complete surveillance system will make them ideal ones and you will never regret your $7. These smoke detectors will pay for themselves and will not demand special maintenance too. There’s just a thing that you have to keep a check on – dust. Dust can clog your indicators and cause false alarms. So to avoid them, it is better to keep your detectors clean.  Hope this article motivates you to buy a detector for your place to make it fire-safe!

Rohan Sharma

Rohan Sharma is a gadget wizard, an active blogger, and an eminent speaker. With more than 10 years of experience to his credit, Rohan has always been a pertinent contributor to the security industry. He is closely associated with Revo America, a well-renowned security products manufacturer and retailer. Needless to say, Rohan boasts for paramount and credible products only, with Revo's being his favorite.

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2 Responses

  1. madhu says:


  2. Rohan Sharma says:

    thanks madhu