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