Will smoke detectors keep your home safe?

(KPRC) It's the middle of the night and your house catches fire. At this point, the most valuable thing in your home is your smoke detector, which is designed to sound the alarm when fire breaks out. That smoke detector's sole purpose is to wake you up so you can get your family out as quickly as possible.

[WEB EXTRA: Smoke detector safety ]

"They were saying 'Daddy, Daddy, please help us, we gonna burn, please Daddy help,'" said Brian Robertson.

Those were the terrible screams of panic that woke Robertson last Memorial Day as his home filled with thick, black smoke. His house was on fire with his 10 kids inside.

Robertson described the flames and the sound of windows popping as he ran through the smoke to save his children, but one thing was missing, the sound of smoke detectors. He said that although he had two working smoke alarms with fresh batteries in them, the smoke detectors never sounded the alarm.

"Even with all that smoke that was coming into the rooms, we still didn't get no sound from the smoke detectors. They never made a sound," Robertson said, shaking his head.

The Robertsons said they had the most common type of smoke detectors, called ionization smoke detectors, which are used in 90 percent of American homes, according to the National Fire Protection Association.

Using ionization technology, experts say these smoke detectors work well in big, flaming, fast-moving fires but not in slow, smoldering, smoky fires, the kind of fires that kill most people at night.

Don Russell is a scientist at Texas A&M who has tested hundreds of smoke detectors over the last 20 years inside a special fire safety lab. He said ionization smoke alarms can take way too long to warn your family of fire, if a slow, smoky fire breaks out in your home.

"If you have an ionization smoke detector in a slow, developing fire, that fire may burn for 10 minutes, 20 minutes, 50 minutes or more, before that smoke detector sounds," Russell said.

News 6 Investigated.  Working with firefighters, we decided to test the ionization smoke detector side by side with what's called a photoelectric smoke detector.
The photoelectric detector works with completely different technology and is said to be much, much faster at detecting slow, smouldering fires.
We filled two glass tanks with polyester fiber and inserted a soldering iron in each tank to create heat. Then we added tiny cameras and started our stop watch to measure how much time it would take for the ionization detector and the photoelectric detector to go off.

With tiny puffs of smoke swirling inside both tanks, the photoelectric detector went off at exactly four minutes, five seconds.
But inside the other tank, five, 10, 15 minutes went by with no alarm at all.

Finally at fifteen minutes, thirty seconds, the ionization smoke detector sounded its warning. That's nearly four times slower than the photoelectric smoke detector.
In a real fire, firefighters say this could have been very dangerous, even deadly, because fires can double in size every five to seven minutes.

Fire experts say, make no mistake: Smoke detectors save lives and are vital for your family's safety.
So what should you do?
Russell said, ideally, you would have both types of smoke detectors in your home.
"The easiest thing is to buy several photoelectric smoke detectors and mount them right next to your existing ionization smoke detectors, so you are protected", Russell said.

The price difference between ionization detectors and photoelectric detectors is about $10, and smoke detectors that employ both technologies are also available at most hardware stores.