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What Are Photoelectric Smoke Alarms?

Smoke alarms are essential safety devices that are recommended for all buildings. For best results these alarms should be placed on each floor of a structure and be located both inside and outside of all rooms where people sleep. Smoke alarms are generally one of two different types, either ionization or photoelectric alarms. They work in two different ways to accomplish the same task. While photoelectric smoke alarms are sometimes considered the best option, more homes have ionization alarms installed in them in the United States.

  1. How They Work

    • Photoelectric smoke alarms work by using a small light source inside the alarm that is captured by a light sensor. When smoke enters the device the beam of light is scattered by the smoke interference. The sensor picks up on the change in the light beam and sounds the alarm to notify occupants of the smoke and the fire that is causing it.

    Supposed Advantages

    • According to the Fire Safety Council, photoelectric smoke alarms have some inherent advantages over the popular ionization alarms, although there are conflicting arguments about which is better. One supposed advantage is that the photoelectric alarm is quicker to sound when there is heavy smoke in the room and less likely to be set off by steam from cooking in a kitchen, which results in fewer false or "nuisance" alarms. The photoelectric alarm is also free of the radiation emissions found in ionization models. While the ionization smoke alarms are not known to emit enough radiation to be harmful to humans, some people prefer to eliminate radiation in the home completely.

    Best Uses

    • The best use of photoelectric alarms is in places where false alarms may be common. Kitchens are an ideal place for photoelectric alarms because of the lower likelihood of steam setting them off. But they are also considered quick to react to smoldering fires like the ones you might have in a living area where furniture or other slow-burning, smoldering fires might happen.

    Popularity

    • Photoelectric smoke alarms are popular in some places, but they are not the leader in home smoke alarm systems in America. There are more ionization smoke alarms in American homes than photoelectric alarms. This is likely because most people do not know the difference in the two types and go solely on price. Ionization alarms are generally a bit cheaper. In commercial buildings it is common to find photoelectric smoke alarms, and in Europe ionization alarms are not sold at all because of the radiation factor.

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