Worcester Polytechnic Institute:
International Smoke Alarm Legislation & Technolgy in Residential Structures
 
“A group of fire protection authorities across the world, including Boston’s Deputy Fire Chief 
 Joseph Fleming and New Zealand’s Adrian Butler, are leading the push towards requiring
 photoelectric smoke alarms in all dwellings.”chieffleming.htmlshapeimage_4_link_0

WPI Smoke Alarm Legislation
& Technology Study

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“However, combination units also have their drawbacks. Detectors can be combined using either an
 “AND” gate or an “OR” gate (Ian Thomas Interview, Appendix L). An OR gate will sound an alarm if
 the unit receives a signal from either one of the detectors. This means that the unit will sound at the
 earliest possible time, but also that the unit is susceptible to the most nuisance alarms due to the
 cumulative weaknesses of each detector. A unit designed with an AND gate will not sound
until it receives a signal from both detectors.”
Note:
Fleming, Butler and other fire protection authorities do NOT advocate
the use of combination ionization/photoelectric smoke alarms.

WPI Study, ‘Executive Summary’ page x, para 1

Combination Ionization/Photoelectric Smoke Alarm Technology

WPI Study, 4.1.3, ‘Combination Alarms’, page 26, para 2

“It must also be noted that, due to the frequency of nuisance alarms from current ionization
 technologies, combination detectors are likely to be disabled by a consumer, rendering them
 useless to warn occupants of any fire.”

WPI Study, 4.1.8, ‘Conclusion’, page 35, para 1

Worcester Polytechnic Institute (WPI):
International Smoke Alarm Legislation & Technology in Residential Structures
A Review for Fire Protection Association Australia
May, 2009fpaa.htmlshapeimage_9_link_0

Founded in Worcester, Massachusetts, USA, in 1865,
WPI is one of America’s oldest technological universities.

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The Combo Con
The truth about combination ionization/photoelectric alarms Here > > >combocon.htmlshapeimage_15_link_0