How smoke alarms became installed in nearly 100% of US homes
While smoke alarms are installed in almost 100% of homes, approximately 30% of alarms don’t work due to aging, removal of batteries, or failure of the homeowner to replace dead batteries.
In 1915, people living in homes or apartments could expect that if their home caught fire, they’d have a one in ten chance of that fire killing them.
One hundred years later, the statistic has dropped to a one in one hundred chance of dying from fire in your home or apartment. The key change agent in those statistics is without a doubt the invention of the practical, inexpensive home smoke alarm.
Smoke detectors have been around since the late 1890s. George Andrew Darby patented the first heat and smoke detector in 1902 in Birmingham, England. Twenty years later, Swiss physicist Walter Jaeger was working to invent a sensor for poison gas, but was failing. Sitting at his desk, he lit a cigarette and was startled to notice his “poison” device was responding to the smoke emitting from his coffin nail. His work translated into the road map for modern smoke detectors.
In 1939, another Swiss physicist Dr. Ernst Meli developed a device with an ionisation chamber that could detect gasses in underground mines. He also invented a cold-cathod tube that could amplify the small electronic signal created by the detection mechanism to a strength sufficient to trigger an alarm. The result was the ionisation smoke alarm.