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Reliability: Ambient Conditions

Tip 41: Changing breath room ambient conditions can reduce "system calibration check" and "system blank test" reliability. Any infrared-based approved instrument such as the Intoxilyzer® 8000C has no true zero. Zero floats up and down depending on, inter alia, the environment of the breath room and the sample chamber. Adding some ethyl alcohol to the room air affects the air sucked into the breath tube and then into the sample chamber during an air blank. Zero needs to be re-established frequently because the baseline voltages in the instrument may be changing (see DVM blog entries) and because the ambient environment may be changing. The instrument constantly re-adjusts.

If, for example, the room is full of ethyl alcohol floating in the air, a cal. check result of 90 to 110 mg/100mls on the approved instrument/wet-bath simulator/simulator thermometer system, may not be very helpful in assessing reliability of the approved instrument, if the wet-bath simulator contains 100 mg/100ml target solution. The correct target, using 100 solution, may become 80 to 100 mg/100mls if there is 10 mg/100mls ethyl alcohol in the breath room air. The correct target, using 100 solution, may become 70 to 90 mg/100mls if there is 20 mg/100mls ethyl alcohol in the breath room air. The correct target, using 100 solution, may become 60 to 80 mg/100mls if there is 30 mg/100mls ethyl alcohol in the breath room air. The correct target, using 100 solution, may become 40 to 50 mg/100mls if there is 50 mg/100mls ethyl alcohol in the breath room air.

This phenomenon is described, to a limited extent, in the 2013 CFS 8000C Training Aid pp. 69 to 70 of 238. Notice the references to "baseline" and "purge fail". See the 2018 CFS 8000C Training Aid p. 70 and note the effect they state therein on "system calibration check". They acknowledge it will be lower than it should be. The "system calibration check" becomes unreliable as a control test.



page 70 excerpt
Excerpt from p. 70 of 240 in CFS Intoxilyzer 8000C Training Aid

This phenomenon can be demonstrated if one has an available Intoxilyzer® 5000, 5000C, 8000, or 8000C and two wet-bath simulators. One simulator contains 100 target solution and is attached to the calibration port in re-circulating mode. A second wet-bath simulator contains 10, 20, 30, or 50 mg/100mls solution and is attached to the breath tube inlet. The simulator solution attached to the breath tube, the contents of the breath tube, and the IR instrument need to be at equilibrium at AI cold power-up to avoid a sudden change in concentration (up or down) that triggers an ambient fail error message. In this way the person performing the experiment simulates a breath room, that already contains ambient alcohol at power-up, or a breath room where the ambient alcohol is rising slowly. The phenomenon is illustrated by the following videos using Intoxilyzer 5000s.


In the following two videos, the experimenter was simulating the presence of ethyl alcohol in the room's ambient air by attaching wet bath simulators containing alcohol standard to the breath tube. On both the Intoxilyzer 5000 (and 5000C) and Intoxilyzer 8000 (and 8000C) the instrument samples room air through the breath tube. "Normal" ambient air is sucked into the instrument by the Intoxilyzer to enable it to establish or adjust zero. If the air sucked into the breath tube is compromised (such that it does not really represent the true zero state of the room) then zero is set or reset at the wrong place and so cal. check and subject test indications will not be reliable.

http://youtu.be/Bm0v0KEyT_g

http://youtu.be/xma5bGItq4Q

The CFS 8000C 2013 Training Aid at page 70 of 238 states in Bold: "Subject test results will not be overestimated by alcohol in the room air."

With respect, overestimation of subject test results is not the point. Evidence to the contrary is not the point defence lawyers will raise. Rather, subsequent subject tests will be unreliable, both under the old law, and according to C-46 section 320.31(1)(a), because:

1. the instrument's baseline zero has been adjusted for subject tests, and

2. more importantly, because the reliability of the subject tests is based upon the reliability of the calibration checks, the calibration checks are unreliable, because the instrument's baseline has been adjusted prior to the cal checks.

A section 258(1(c) defence, is no longer available. It is no longer a defence to prove "evidence to the contrary" or "evidence tending to show a BAC below 80". Parliament has abolished any defence related to contradiction of accuracy by means of a Carter defence.

With Bill C-2, Parliament replaced the Carter defence with reasonable doubt about scientific reliability. Lack of scientific reliability of subject test results was a defence pre-C-46. A key aspect of subject test reliability is alcohol standard reliability. If we can't count on the true target value being 100 mg/100mls (90 to 110 mg/100 ml range), then subject test scientific reliability has been compromised and should result in reasonable doubt.

Please re-read R. v. St-Onge Lamoureux and study the use of the words "reliable" and "reliability". Note the separation of the concept of "reliability" from "accuracy", "precision", and "specificity" in the quote therein from Hodgson (see the Home page for duimetrology.com under the anchor "The Hodgson Report"):

[33] Parliament’s decision to resort to the presumptions of accuracy and identity to help combat the problems resulting from drinking and driving is not at issue in this appeal; rather, what are at issue are the means available to rebut those presumptions. Parliament intended to limit the evidence that can be adduced to raise a reasonable doubt about the reliability of the test results. As can be seen from the legislative history, the objective of the amendments, which form part of a scheme whose purpose is to “reduc[e] the carnage caused by impaired driving” (Orbanski, at para. 55), was to give the reliability of the test results a weight consistent with their scientific value.

[34] The reliability of breathalyzer tests was explicitly mentioned in the abstract of Hodgson’s report:

The scientific basis for evidential breath alcohol testing is well established. Experiments derived from a recognized scientific law in physics have proven the scientific validity of breath analysis to determine alcohol concentration in the blood. Instruments designed to measure breath alcohol content are based on technology that is capable of producing scientifically sound results. Like Canada, every country that embarks on evidential breath alcohol analysis subjects these instruments to a rigorous evaluation process. These processes determine whether the instruments meet the scientific standards for accuracy, precision, reliability and specificity. [p. 83]

[41] It should also be mentioned that the new provisions do not make it impossible to disprove the test results. Rather, Parliament has recognized that the results will be reliable only if the instruments are operated and maintained properly, and that there might be deficiencies in the maintenance of the instruments or in the test process. What the new provisions require is that evidence tending to cast doubt on the reliability of the results relate directly to such deficiencies.

[48] The prosecution gains a clear, albeit limited, advantage from the requirement, since evidence to the contrary is limited to the real issue: whether the test results are reliable. The evidence to be tendered relates directly to an instrument that is under the prosecution’s control. The prosecution must of course disclose certain information concerning the maintenance and operation of the instrument, but it is free to establish procedures for tracking how such instruments are maintained and operated. Moreover, the prosecution has control over the people who maintain and operate the instruments.

[52] At this step in the defence process, it must be accepted that the judge will not consider evidence showing a connection between a deficiency and the determination that the blood alcohol level of the accused exceeded the legal limit unless the accused has already proved that the instrument was malfunctioning or was operated improperly. At this stage, if the arguments made by the defence are frivolous or trivial, they will not cast doubt on the proper functioning or operation of the instrument, and the defence must fail. The facts of Crosthwait provide a good illustration of this. In that case, the accused had tried to raise a doubt that the instrument had functioned properly by arguing that the technician had not compared the air temperature with the temperature of the solution before making the analyses. The mere possibility that the instrument had malfunctioned was not evidence to the contrary that could cast doubt on the reliability of the results.

53] Thus, it is necessary to proceed on the basis that the accused must not simply show that a deficiency is possible, but raise a real doubt that the instrument was functioning or operated properly. In short, if Parliament’s objective was to eliminate frivolous cases, that objective would be achieved through the assessment of the evidence by the trier of fact.

[72] In the context of the case at bar, as I mentioned above, the expert evidence accepted by the courts over the past few years has established that breathalyzer tests are very reliable, provided that the instruments are operated and maintained properly.

[78] Although Parliament now requires evidence tending to establish a deficiency in the functioning or operation of the instrument, this does not mean that there are limits on the evidence that can reasonably be used by the accused to raise a doubt in this regard.

It is respectfully submitted that unless the design of the approved instrument (ambient fail systems), and the protocol actually followed by the Qualified Technician, control for Intoxilyzer/the wet-bath simulator / alcohol standard unreliabilty caused by, significant ethyl alcohol in the breath room air, there should be a reasonable doubt about the scientific reliability of the subject tests. However, post C-46 there is no "evidence to the contrary" 258(1)(c) defence. Reliability, potentially lowered indications on subject tests, has been compromised, but that is not a defence post C-46.


Instead, defence lawyers should look at the "blank test" and "system calibration check" provisions in 320.31(1)(a). If the Crown cannot prove reliability of the "blank test" or prove reliability of the "system calibration check" beyond a reasonable doubt then they cannot rely upon "conclusive proof" in 320.31(1) and must prove their case without resort to the conclusive proof presumption. If cal. checks have been lowered by changing ambient conditions, then they are giving false assurances of Intoxilyzer reliability if they appear to indicate normalcy i.e in the usual 90 to 110 range.


Be careful though to call expert evidence. You cannot successfully argue these concepts without expert evidence. The Crown may prima facie prove its case using a Certificate, Intoxilyzer Test record, or hearsay. Your brilliant cross-examinations of the breath tech probably won't be enough.


Although the Crown may be able to establish prima facie proof of the conditions precedent in 320.31(1)(a) (specifically the blank test) using, for example, a Certificate of a Qualified Technician, the facts stated in that Certificate (the three conditions precedent in 320.31(1)(a) including the "blank test") can be displaced by Interpretation Act "evidence to the contrary" and reasonable doubt. You'll need "evidence to the contrary" and an expert to displace the Interpretation Act presumption.


Be sure to read subsequent blog entries dealing with DVM : differential voltage monitoring. They will help you to understand a further layer of floating in the baseline zero. After all, an indication of BAC by voltage is really only a calculation of one electrical signal at one time minus another electrical signal at a prior time. Each of those electrical signals has its own zero point and variability. Be sure to laugh at our videos showing wandering DVM in aging (or flooded) machines that sometimes pass diagnostics and cal. checks and sometimes are totally bonkers.


How do police control for these environmental issues and do good forensic science the way Parliament and the Supreme Court of Canada expect?

  1. Stop fudging ambient fails into passes by manipulating the breath tube to positions not contemplated by the manufacturer's design of the instrument.

  2. Exercize caution with respect to ethyl alcohol or chemical interferents in the breath room (i.e. avoid fingerprinting equipment and hand cleaners in the breath room)

  3. Follow their training from the CFS or other provincial lab.

  4. Follow their protocols from the ATC.

  5. Use only approved instruments that are relatively new (i.e. recent factory calibration)(as in Jackson) or recently re-calibrated by an independent service centre . (i.e. short calibration intervals) as in Vallentgoed and Gubbins.

#reliability #truezero #ambientfail #tip

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