Andrew Sullivan points to an interesting post on Freakonomics, where a deputy fire chief questions whether smoke detectors have made as much a difference as we think they have. Their use has jumped from 10% of homes in 1975 to over 95% today, and the number of fire deaths in that period has dropped in half. Joseph Fleming writes:
The death rate was trending down before smoke alarms and continued to trend down after they saturated the market. It does not appear that ionization smoke alarms affected the trend line. NIST inexplicably ignores the trends in better building codes, reduction in smoking, better firefighting equipment, and better emergency medical care as likely reasons for the reduction in fire deaths.
He is probably right about it not being the smoke detectors, because in many cases they have been disabled due to false alarms. Certainly in our house, it is be best way to tell if the toast is ready. Like most people we have ionization smoke detectors, where a tiny bit of radioactive material emits alpha particles. When smoke gets in, it absorbs the particles, breaking the circuit, and setting off the alarm. These are popular because they are battery powered; we have two that have lithium batteries and will run for twenty years without changing. (There was some concern a few years ago about terrorists hoarding smoke detectors to harvest the Americium in them to make a dirty bomb, but it would have required about 10,000 of them)
Photoelectric smoke detectors have to be hard wired; they detect smoke when it blocks the light from reaching a photocell. They are less sensitive and less subject to false alarm. They are required in some building codes in new housing, but the great majority are still ionization types. And neither gets to the root of the problem, of actually stopping fires.
Instead of just having detectors, we really should have sprinklers in every living unit. And not just because of fire; also because of our health. To protect people from fire, flame retardants are put into just about everything; as I noted in an earlier post,
despite being tied to cancer, reproductive problems, irreversible changes in brain development – and being found in the breast milk of many women in the US. These and dozens of other flame retardant chemicals are used in drapes, carpets, upholstered furniture, electronics – pretty much anything in your home that contains polyurethane foam, textiles or plastics.
It isn't enough to just have better smoke detectors; we need to be able to ensure that when a fire starts it can be put out quickly and automatically. Then we can get rid of all these chemicals that are doing us no good at all.