Therefore, if smoke enters the detecting chamber, some of these ionised air molecules will react with the smoke, causing a change in electrical behaviour — hence triggering the alarm to go off. Whilst perfectly safe to residents, ionisation fire alarms are banned in several countries as they contain small quantities of radioactive material Americium meaning there are storage and disposal issues. It is therefore expected that the UK will soon follow suit. Ionisation alarms are also more prone to false alarms in domestic premises compared to optical and multi-sensor alarms available.
Of these, optical alarms are marginally less sensitive to fast flaming flames, so the Fire and Rescue Service advocate installing multi-sensor alarms around the home. These provide residents with ultimate fire protection as they work to detect two different signs of fire heat and smoke , and so have a faster response time to all types of fires.
Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Home Improvement. Home DIY. Household Safety. How Smoke Detectors Work. Do you know how they work? Photoelectric Detectors " ". It's a pretty big smoke detector. It is not very sensitive.
Did You Know? Ionization Detectors: Ionizing Radiation Ionization smoke detectors use an ionization chamber and a source of ionizing radiation to detect smoke. Ionization Detectors: Ionization Chamber " ".
Inside an Ionization Smoke Detector " ". Why does smoke come from a fire? How do smoke detectors intercommunicate? Cite This! Try Our Sudoku Puzzles! More on This Topic. Smoke Alarm Outreach This webpage includes infographics, frequently asked questions, and good information about smoke alarm effectiveness and importance. Skip to main content. Contact Us. Americium in Ionization Smoke Detectors. Radiation Facts. Some smoke detectors use very small amounts of radioactive material to detect smoke.
While they are safe to use in your home, never tamper with an ionization smoke detector. Replace the batteries in your smoke detectors every year. The States Each state has a program to protect people from radiation exposure. Nuclear Regulatory Commission NRC Licenses are required for anyone who sells, uses, or disposes of radioactive material. Smoke alarms detect fires by sensing small particles in the air using a couple of different kinds of technologies. Once they detect those particles above a certain threshold, they signal the alarm to sound so that you and your family can get to safety and call Smoke alarms save lives.
Smoke alarms detect particles in the air. They most commonly do this using two types of detection technologies. First, there are ionization detectors. These use a small bit of safely shielded radioactive material that electrically charges, or ionizes, the air molecules between two metal plates. This produces a small electric current flowing from one plate to the other in the air. When particles enter the chamber, they attract the ions and carry them away, reducing the current.
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