Utah Intoxilyzers Calibrated With Breath Alcohol Simulators At 34 Degrees C. Penalize Arrestees By Failing To Measure Actual Breath Temperature

David Rosenbloom a Utah DUI Attorney explains inaccurate field sobriety tests.

FACT: Utah Law Enforcement calibrates all Intoxilyzers used in DUI arrests monthly, using a Guth model simulator set at 34 degrees Centigrade, + or - .01 degrees, using a .10 Guth alcohol / water solution that is + or - 2%. However, since none of the Utah Intoxilzyers used in DUI enforcement measure human subject breath temperature, and since human breath temperature has been scientifically proven to vary between 33 and 37.4 degrees C, and since every degree increase C above the set point of 34 degrees equals a 6.7% increase in reported blood alcohol level (BAC); arrested subjects in Utah are routinely subjected to higher than actual blood alcohol levels, ranging from 0 - 24% higher, depending on the subjects actual breath temperature. Consider, as shown below, how sensitive these calibrators are to even room temperature changes!

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Andersson and Jones, Room Temperature Influences on the Performance of Some Breath Alcohol Simulators; Dubowski, Breath-alcohol Simulators: Scientific Basis and Actual Performance, 3 Journal of Analytical Toxicology 177 (1979)

David's Plain Language Analysis / Synopsis: Guth calibration checks are not adequate as the simulators used vary with room temperature, while Guth 210021 and 34C simulators were less able to maintain temperature required than Alcotest CU34 simulator. Room temp used 17, 22 and 27°C. Goal was to maintain 34°.

ARTICLE
Since Dubowski’s 1979 study saying simulators are fine temperature regulation has improved. This study shows that problems still exist with unregulated temperature of the metal simulator head and condensation of water in connecting tubing in the upper part of the jar.
Four breath alcohol simulators, Alcotest CU 34(A), Guth 210021 (B), Guth 34(c), and one modified Guth 34C (D), were examined at different room temperatures and the concentrations of ethanol and water in the simulator effluent were measured. Tests were conducted at room temperatures of 17, 22, and 27°C. Alcohol solutions were prepared to yield 0.50mg/L (0.105 g/210 L) at 34.0°C. Two gas wash bottles were arranged in tandem and charged with the standard ethanol solution and then completely immersed in circulating water at 34.0°C. This alcohol solution was used to create a reference wet-gas standard. A specially constructed infrared (IR) instrument was used to measure the concentration of ethanol (3.47 µm) and water (2.57µm) in the effluent gases. The solution temperature in each simulator was adjusted as close as possible to 34.0°C at the room temperature in each simulator was adjusted as close as possible to 34.0°C at the room temperature of 22°C. The results were expressed as the percentage of the reference gas ethanol concentration after correction for ethanol depletion. The following average deviations from target (100%) were obtained for ethanol at room temperatures of 17, 22, and 27°C. (A) -2.6, -0.04, 0.4; (B) -2.6, -0.7, 0.1; (C) -2.3, -2.0-1.2: (D) 0.1, 0.1, 0.1. The corresponding average deviations from target values for water vapor were; (A) -5.7, 0.1, 6.4; (B) -20.2, -10.9, 0.9; (C) -15.0, -5.8, 4.9; (D) 0.2, -1.1, 1.5.
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