LETTER- In a fire, seconds count

With all the care and resources devoted to your cover story on smoke detectors ["Alarming: Most smoke detectors don't detect deadly smoke," July 10], we're disappointed that the article did not actually quote the documents it mentions from our website at the National Institute of Standards and Technology (NIST), as they specifically address many of the points raised in the piece.

As our website smokealarm.nist.gov details, NIST research has shown that both types of smoke detectors— ionization and photoelectric– when properly installed and maintained, provide enough time for escape under many fire scenarios.

Consistent with prior findings from other research groups, NIST studies have found that ionization alarms provide somewhat better response to flaming fires than photoelectric alarms and that photoelectric alarms provide often considerably faster response to smoldering fires than ionization alarms. 

Although Boston Deputy Fire Chief Jay Fleming states in the article that ionization detectors are "nearly useless," the Hook's own flaming fire tests show that the in-room ionization detector activated 35 seconds sooner that the photoelectric. NIST studies of escape times have found that seconds do count in many flaming fires because of the rapid buildup of heat and toxic gases.

Ionization detectors respond 50 seconds earlier on average than photoelectric detectors in the NIST flaming fire experiments. Many fire-safety related agencies and organizations recommend that a mix of both ionization and photoelectric detector types or combination units be present in the home.

In February, NIST posted a detailed set of questions and answers that address the concerns raised in the article, including recommendations regarding the placement of ionization detectors to reduce the incidence of nuisance alarms. These questions and answers will continue to be updated as new information becomes available. Your readers may find this document on our website, http://smokealarm.nist.gov/pdf_files/SmokeDetectors_Q&As_Feb2008.pdf. 

Alarm response is an important issue, and NIST is conducting new research to examine factors that affect detector response and identify more effective life-saving detection strategies.

Shyam Sunder
Director, Building and Fire Research Laboratory
National Institute of Standards and Technology

Gaithersburg, MD



As a fire protection professional, we recommend repllecement of smoke detectors- both photeoelectric and ionization type every ten years. However, the industry does not seem to support this. Commercially, depending upon location, inspectioons and tests of fire alarm systems are done quarterly, semi annually or yearly, but residentially- never.
I belive this is a source of liability on the manufacturers part not to clearly state that every ten years all detectors should be replaced, and at least annually all detectors be inspected,tagged with the date of inspection (perhaps under the detector in a form attached to the detector by the MFG, and the expiration date of the detector, ten years after initial installation.

As to the article: UL tests most of the smoke detector in use today. They test both photo and ionization types to the same conditions and classify them both as "Smoke Detectors". Perhaps we should have separate standards. As author Sunder points out that detectors when properly installed and maintained are effective. Proper installation should consider what fuels could burn in a specific enviroment and the rate that they could burn at. These two factors must be considered in "proper installation".
As to Mr. Garlands comment: If the "fire protection professionals" are not enforcing current NFPA 72 requirements for 'qualified' technicians how will we ever get to this point of replacing detectors in both commercial and residential facilities?

In view of thirty years of experience, I fully support Mr. George P. Garland. but I do not agree that it is not soley liability on the manufacturers part, it is also from installer side.

It is very interesting to note that Mr. Sunder mentioned the two tests where Ionization detectors alerted 35 and 50 SECONDS faster that photoelectric detectors but failed to mention the tests where PHOTOELECTRICs alerted 17 to 55 MINUTES faster than the ionization detectors. Incidentially, these were smoldering fire tests, the leading cause of fire deaths. There is a story here.

NIST once agains fails to tell the truth about ionization smoke alarms.

Mr Sunder states: ". . . that both types of smoke detectors . . . provide enough time for escape under many fire scenarios."

So, if you have one thousand smoldering fires and ionization detectors safely activate in 100 of those fires then NIST's statement, using the word 'many', is technically correct. After all, 100 fires is 'many' fires isn't it - all you have to do is not think about the 900 fires when the ionization alarms fail to safely activate and there is not a problem.

Here in Australia, some of our Government agencies have dug deep and discovered the truth. AFAC & FPAA are now warning that ionization smoke alarms do NOT give sufficient time to escape from smouldering fires. Fire Departments in Australia and New Zealand are now required to ONLY recommend photoelectric smoke alarms.

For more on NIST, visit their page on our website:

and make sure you check out The Hook's page:

Adrian Butler, Chairman
The World Fire Safety Foundation
Gold Coast, Queensland, Australia