A new study on the reliability of common household smoke detectors contradicts the findings of a CTV documentary, and concludes the devices easily meet national safety standards.

The study was commissioned by Health Canada after a January report on CTV's W-Five found the detectors failed to sound their alarms within the time limits required by Canadian standards.

W-Five asked engineers at Texas A&M University to look at 11 models -- 10 ionization models and one photoelectric model -- in their study. The report featured tests of smouldering fires, including some that burned for more than 15 minutes, filling a room with smoke before any of the ionization smoke alarms finally sounded.

But a special round of tests conducted by Underwriters' Laboratories of Canada found the 11 models passed their tests 100 per cent of the time.

ULC gave few details on how it conducted its tests but said the process occurred "in an open manner" and was witnessed by fire officials from the Standards Council of Canada, Canadian Association of Fire Chiefs, and the Consumers Association of Canada.

"Both ionization and photoelectric smoke alarms are tested in exactly the same manner and meet the same requirements -- they both provide needed protection," says John Roberts, President and CEO of ULC.

"ULC was glad to conduct testing for Health Canada, but we're concerned that the testing became necessary because a sensationalized story, based more on television ratings than on scientific findings, has cast doubt on smoke alarms," said Roberts.

Ontario's Fire Marshal Bernard Moyle reinforced the findings. He says smoke detectors have helped reduce the number of fire deaths in his province by 60 per cent over the past 20 years.

Robert Hurst, vice-president of CTV News and executive producer of W-Five, says that he has not read the ULC report but stands by his show's story.

The show says the tests were conducted accurately in what it calls "real world" fire situations. It's even invited ULC to come on television and compare their test results.

Health Canada still plans to have another look at existing standards for smoke detectors, to see if they need to be improved.