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(c) Copyright July 09

1. 1. •“As illustrated in the article, the various types of fire detectors provide different levels of risk which supports the need for a change in the current thought process of many fire officials. Certain types of fire detectors are more reliable for the different types of fires, therefore, recommendat-ions as to the type and location of the fire detector should include the type of fire ignition that would most likely occur and the most reliable detector that can be installed in that location.”
      
      

   2. •“For example, during a smoldering ignition fire, the photoelectric smoke detector offered the most reliable method of detecting the fire while the room of origin was still in a tenable condition.”
      

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   4. •“The probability of the failure of the photoelectric detector to detect a smoldering ignition fire is 4.06% while the ionization detector provided a 55.8% probability of a failure in a similar type of fire. This high probability of a failure of the ionization detector can be contributed to a number of factors such as performance under normal conditions and an inability to consistently detect smoldering smoke particles. This is a very important consideration since most of the fires that occur in residences start out as smoldering ignition fires.”
      

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   6. •“During a flame ignition fire, the photoelectric smoke detector had a 3.99% probability of a failure to detect the fire while the ionization smoke detector probability of failure to detect the fire is 19.8%.”

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1. 1. continued . . .

Slides 23 and 24

Now what I think should be the Gold Standard study.  Researchers at Texas A&M University, along with support from the University of Colorado and Iowa, did a three year smoke alarm study in the 1990’s.  They were concerned that UL’s testing of smoke alarms, by putting a smoke detector in a wooden box and then by forcing smoke through it, was not as good as open field testing.  Texas A&M’s testing was a fault-tree-analysis model designed by Bell Laboratories for the United States military.  After three years here is what their research concluded:

1. -In a Smoldering fire the ionization detector had a 55.8% failure rate (this means the person died) to the photoelectric detectors 4.06% failure rate.
   

2. -In a Flaming fire, where the ionization supposedly has a few seconds advantage, the ionization had a 19.8% failure rate, to the photoelectric detectors 3.99% failure rate.