Smoke Detectors

How do Smoke Detectors Work?

Smoke detectors are a very important part of any home. Although you’re hoping you never hear yours go off, it’s important to have one, just in case. You’ll have the peace of mind knowing that if there IS a fire, your smoke detector will alert you. But do you know how?

There are two different types of smoke detector. The first and most common is an ionization smoke detector, and the other kind is an optical smoke detector. Let’s break down how each type can detect a fire.

Ionization Smoke Detectors

How does it work?

This type of smoke detector works by using chemistry to detect smoke particles. It features an open space called the ionization chamber that is open to the air to allow smoke particles to enter. This chamber contains something called americium that continually releases small bits of radioactive material.

When these bits of radioactive material interact with the air in the chamber, they become positively charged ions and negatively charged electrons. These atoms create an electrical circuit by flowing between the electrodes in the smoke detector.

When there’s a fire

If there is a fire, smoke will clog up the chamber, which ceases the flow of atoms and breaks the circuit. The alarm will immediately sound. The alarm will keep sounding until the chamber is clear and there is no more smoke.

Optical Smoke Detectors

How does it work?

This type of smoke detector works by using an infrared light beam to detect smoke. It also uses a chamber, but this one doesn’t contain radioactive material. Instead, it’s just an opening for air.

The infrared beam shoots across the inside of the chamber from a tiny LED to a photocell. This photocell can detect the light and will generate electricity if it detects the infrared light.

When there’s a fire

In case of a fire, smoke is directed upwards due to the heat from the fire and enters the chamber. When smoke enters the chamber, it blocks the light to the photocell, causing it to no longer produce electricity. When this happens, the alarm will go off.