An NBC investigation has found that the most common type of smoke detector, used in 90 percent of homes, may not save you from a smoldering fire because they work better when in the vicinity of fast flames. The reason this familiar device is popular is because it’s inexpensive, easy to find, and and it’s an alarms that relies on ionization technology. They work well to detect fires with fast flames, but experts say they may not save you in smoldering smoky fires that can strike while you sleep, even though you assume they’re going to sound when there’s smoke. NBC ran tests, conducted under the supervision of a Texas A & M scientist, placing three ionization detectors in a room, then setting a couch on fire. And as toxic smoke is building, it takes 36 minutes for the first detector to go off, but there’s another technology out there that gives you better warning in these fires. it’s called a photo electric detector, and with a photo electric device next to those three ionization detectors. 17 minutes in, with barely any smoke in the room, the photo electric sounds the alarm. the ionizations? they’re still silent for another 21 minutes. even with smoke everywhere.