Thursday, January 11, 2007

Alabama Drops It's Old Technology in Favor of Draeger because of Temperature Correction

ABSTRACTS FROM THE 45th ANNUAL MEETING (WOLFVILLE, NOVA SCOTIA, AUGUST 12–15, 1998) Alabama’s Field Evaluation of the Draeger Alcotest 7110 M K III: Breath Temperature CorrectionAuthors: Dale A. Carpenter, Ph.D. and James M. Buttram, Ph.D.

Over the past several months the Alabama Department of Forensic Sciences has been conductingan evaluation of the Draeger Alcotest 7110 MK III evidential breath alcohol testing instrument. The Alcotest 7110 MK III is the first commercial evidential breath-testing instrument available that measures a suspect’s exhalation breath temperature. The importance of breath temperature in breath alcohol testing has been mentioned in the literature repeatedly. One aspect of our evaluation was to place two instruments in the field and perform parallel testing of actual arrestees against the current Alabama evidential breath-testing instrument. Almost all (93%, 81%) of the over two hundred collected breath samples acquired on the Alcotest 7110 MK IIIAEs had breath temperatures above 34°C. Our results show a breath temperature range of 32.4 – 36.2°C with a mean of 34.9°C. The influence of temperature on Henry’s Law illustrates the benefit of an instrument capable of measuring a suspect’s exhalation breath temperature and correcting the resulting (BrAC) to the reference temperature of 34°C. Our data indicate an overwhelming number of suspects would benefit from a breath-testing program that utilizes breath temperature correction capability. The Alabama Chemical Tests for Intoxication Program is currently implementing a protocol that will correct or lower a suspects BrAC when an elevated (>34°C) breath temperature exists. In the event that a suspect’s breath temperature is lower than 34°C no correction will be made. The Alabama Breath testing protocol will provide relief to those suspects with BrACs on or about the 0.08% level with elevated breath temperatures.

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