Fire Safety Tips - Smoke Detectors

Center Pigeon Volunteer Fire Department, Inc. P.O. Box 875, Canton, NC 28716    Tel: 828.648.0810



Fire Safety Tips - Smoke Detectors

Installing smoke detectors is the smart thing to do. It's also the safe thing to do.

Follow these tips to help save your life & property from fire:

For minimum protection, install a smoke detector outside of each bedroom or sleeping area in your home.

Keep your bedroom doors closed while you are asleep. Better, install detectors on every level of your home.

Keep your smoke detectors properly maintained. Test them once a week to ensure that the detectors are working properly.

Every Spring and Fall when you change your clocks, remember to change your smoke alarm batteries. Use only the type of batteries recommended on the detector.

Develop an escape plan and review the plan with all members of the family frequently. Be aware that children and elderly people may need special assistance should a fire occur. Establish a meeting place outside the house for all members of the family to ensure that everyone gets out safely. When fire occurs, get out of the house and use a neighbor's telephone to notify the Fire Department

Did you know??

Landlords must install smoke detectors in multiple-dwelling apartment buildings? But it is your responsibility to maintain them!

Most fire deaths occur at home.

Most occur in homes with no working smoke detectors.

So why take a risk? Install smoke detectors! They really do work!
Background of the Smoke Detector

A smoke detector is a device that detects smoke and issues an alarm. Smoke detectors alert people within hearing range; some also interface with a security system or notify emergency services.

A household smoke detector will typically be mounted in a disk-shaped plastic enclosure about 150 millimeters (5.9 in) in diameter and 25 millimeters (0.98 in) thick, but the shape can vary by manufacturer.

Most smoke detectors work either by optical detection (photoelectric) or by physical process (ionization), but some of them use both detection methods to increase sensitivity to smoke. Smoke detectors are usually powered by battery; some are connected directly to power mains — often have a battery as a power supply backup in case the mains power fails.

In either case, it is usually necessary to replace the batteries once a year to ensure appropriate protection if alkaline or carbon-zinc batteries are used.

History of the Smoke Detector

The first automatic electric fire alarm was invented in 1890 by Francis Robbins Upton and Fernando J. Dibble, (US patent no. 436,961). Upton was an associate of Thomas Edison, although there is no evidence that Edison contributed to this project.

It is a widely spread misinformation that the first electric fire alarm was patented in 1902 by George Andrew Darby of Birmingham, England, as this falls 10 years after the real first fire alarm was invented. There is a fun (and seemingly non-confirmable) anecdote regarding Darby's device. Apparently it indicated an increased temperature by closing an electrical circuit to sound an alarm if the temperature rose above the safe limit. The contact was made by bridging a gap with a conductor, or allowing one plate to fall on another. The connection of the two plates was caused simply by a block of butter which melted as the temperature rose.

In the late 1930s the Swiss physicist Walter Jaeger tried to invent a sensor for poison gas. He expected that gas entering the sensor would bind to ionized air molecules and thereby alter an electric current in a circuit in the instrument. His device failed: small concentrations of gas had no effect on the sensor's conductivity. Frustrated, Jaeger lit a cigarette--and was soon surprised to notice that a meter on the instrument had registered a drop in current. Smoke particles had apparently done what poison gas could not. Jaeger's experiment was one of the advances that paved the way for the modern smoke detector.

It was 30 years, however, before progress in nuclear chemistry and solid-state electronics made a cheap sensor possible. While home smoke detectors were available during most of the 1960s, the price of these devices was rather high. Before that, alarms were so expensive that only major businesses and theaters could afford them.

The first truly affordable home smoke detectors were invented by Duane D. Pearsall in 1967, featuring individual battery powered units that could be easily installed and replaced. The first commercial smoke detectors came to market in 1969. Today they are installed in 93 percent of U.S. homes and 85% of UK homes.
However it is estimated that any given time over 30% of these alarms don't work, as users forget to replace, or remove the batteries.
Although commonly attributed to NASA, smoke detectors were not invented as a result of the space program, though a variant with adjustable sensitivity was developed for Skylab.