• Stephen Biss

Ambient Conditions Change Baseline 0 on an IR Breath instrument

This video displays the function of the air blank and ambient fail systems on an IR evidentiary breath instrument such as the Intoxilyzer® 5000C (or 5000 as in this video) and the Intoxilyzer® 8000C (or 8000). In this experiment the room's ambient conditions have been artificially elevated to 50 mg / 100 mls by attaching a second simulator (at 50 mg/ 100 mls and 34C) to the breath tube inlet. Although the 5000 instrument is programmed to flag "Ambient Fail" at 20 mg/100 mls no such error message is produced. This is because the instrument can only compare an unacceptable ambient situation ( 50 mg/100 mls) against the baseline established when the instrument was first powered on (50 mg / 100 mls.) The instrument erroneously considers the 50 mg /100 mls as 00 mg /100 mls. The real danger of this phenomenon is that calibration checks become not reliable - and in this example the 100 mg /100 mls alcohol standard produces a calibration check of 51 mg / 100 mls. COBRA data from the weeks before and after a particular subject test may be very useful in flagging unusually low cal checks that possibly are being caused by ethanol or another chemical interferent in the room air (e.g. hand cleaners, paint, cleaning fluids). Unreliable cal checks do not cause erroneous subject test results but they do compromise the scientific reliability of the subject tests.

#ambientfail #truezero

3 views0 comments

© 2020 Allbiss Lawdata Ltd. All rights reserved. This is not a government web site.



For more information respecting this database or to report misuse contact: Allbiss Lawdata Ltd., 303-470 Hensall Circle, Mississauga, Ontario, Canada, L5A 3V4, 905-273-3322. The author and the participants make no representation or warranty  whatsoever as to the authenticity and reliability of the information contained herein.  WARNING: All information contained herein is provided  for the purpose of discussion and peer review only and should not be construed as formal legal advice. The authors disclaim any and all liability resulting from reliance upon such information. You are strongly encouraged to seek professional legal advice before relying upon any of the information contained herein. Legal advice should be sought directly from a properly retained lawyer or attorney. 

WARNING: Please do not attempt to use any text, image, or video that you see on this site in Court. These comments, images, and videos are NOT EVIDENCE. The Courts will need to hear evidence from a properly qualified expert. The author is not a scientist. The author is not an expert. These pages exist to promote discussion among defence lawyers.


Intoxilyzer®  is a registered trademark of CMI, Inc. The Intoxilyzer® 5000C is an "approved instrument" in Canada.
Breathalyzer® is a registered trademark of Draeger Safety, Inc., Breathalyzer Division. The owner of the trademark is Robert F. Borkenstein and Draeger Safety, Inc. has leased the exclusive rights of use from him. The Breathalyzer® 900 and Breathalyzer® 900A were "approved instruments" in Canada.
DrugTest® 5000 is also a registered trademark of Draeger Safety, Inc.. DrugTest® 5000 is "approved drug screening equipment" in Canada.
Alcotest® is a registered trademark of Draeger Safety, Inc. The Alcotest® 7410 GLC and 6810 are each an "approved screening device" in Canada.
Datamaster®  is a registered trademark of National Patent Analytical Systems, Inc.  The BAC Datamaster® C  is an "approved instrument" in Canada.