Smoke Detectors
Each year people unnecessarily perish in fires. Purchasing smoke detectors and installing and maintaining them properly is a good first step in prevention.There are two basic types of detectors: photoelectric alarms that are activated by smoke particles interrupting a beam of light within the device; and ionization types that contain a radioactive material such as americium-241 that ionizes the air in a small chamber thus creating a weak electric current. When particles from the fire affect the current's flow, the alarm sounds. Both types of device give off a loud piercing wail that no one will mistake for the doorbell.
A controversy rages over which type is the best fire detector. Radiation has always been the major bone of contention between the two factions. Critics of ionization systems ask: Why take any risks when another type of detector, devoid of any inherently dangerous elements, can alert people to fires? Scientists point out that ingestion of even a minute amount of americium-241, which is a waste product from the nuclear cycle, can cause cancer. Admittedly, ingestion is not a likely occurrence; however, the disposal of used units poses very real problems. Consumers are now advised, by means of a small label on the interior of the casing, to return used units to the manufacturer or distributor.
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December 4, 2008