In the U.S., home testing detectors

American TV WHNT of Huntsville, Ala., has tested two types of stand-alone smoke detectors, most commonly used in private homes. Test results so impressed the journalists that they decided to publish them as widely as possible.

In the U.S. market are two types of self-contained smoke detectors, the design of which is based on different physical principles of detection of smoke.

Ionization (radioisotope) smoke detector - is composed of a small amount of radioactive material between two electrically charged plates. Radioactive material ionizes the air in the chamber detector, causing an electrical current between the plates. When smoke enters the process chamber, charged particles "stick" to the particles of smoke, the current decreases, the detector is triggered.

Photovoltaic (optoelectronic) smoke detector - the principle of operation is based on the dispersion of infrared light in the chamber detector smoke particles. When the level of infrared light from the LED on the photocell, srabatyvet anxiety.
Bill Loden, vice president of the American Society of inspectors houses (American Society of Home Inspectors), states that over 95% of the detectors in homes USA is the ionization type. International Association of Fire (International Association of Fire Fighters) warns homeowners from installing radioisotope detectors.

The thing is that the reaction time of the detector to the smoke, which is usually formed in the early stages of a fire in a residential area, much longer than that of the photoelectric detector. In addition to this, the construction of such home nesovreshenna detectors, which leads to frequent false alarms. Reduced people's confidence in fire alarms, and many people do turn off the detectors, leaving his home and family unprotected.

WHNT News 19 journalists have decided to check both the detector. With Bill Lodena, they had visual desonmtratsiyu using aquarium simulates indoors. In the aquarium were placed the following items:

a piece of foam, which is the most commonly used filler for furniture;

soldering iron to heat the foam;

carbon monoxide detector (carbon monoxide, the most dangerous component of the combustion products, poisonous, odorless gas);

smoke detector.

Then placed on the aquarium lid, and takes the time alarms. Also control the content of carbon monoxide.

The value of the response time for the photoelectric detector was 2 minutes and 48 seconds, and for the ionization - 17 minutes, the carbon monoxide level in the case of ionisation detector exceeded 1,000 parts per million (with a value of 200 parts per million, firefighters work on the fire with breathing apparatus).

In the past few years, Vermont, Massachusetts and Iowa have enacted legislation under which accommodation equipment ionization fire detectors either not permitted or required to equip facilities with combined detectors, combining both photoelectric and ionization sensors. A similar law in Tennessee is in the discussion.