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Discussion of Approved Instruments, Approved Screening Devices, Approved Drug Screening Equipment, Alcohol Standards, and Wet-bath Simulators used by Police in Canada to screen at roadside or to establish "conclusive proof" of excess Blood Alcohol Concentration

Purpose - to assist defence lawyers in examining and challenging the "reliability" of aging breath instruments, particularly in Ontario . "Reliability" is not the same thing as "accuracy" or the apparent "accuracy" alleged by police officers. For many reasons, an instrument may appear to be "accurate" (as indicated in the limited printouts from the instrument); yet the "conclusive proof" may not be "reliable" and your client may in fact be innocent. Do you understand the scientific meaning of "reliability" and the distinction between "accuracy" and "reliability"?

This site promotes discussion among defence lawyers in Canada. It deals with transparency in the quality assurance and quality control measures used by police respecting evidentiary breath testing equipment. As instruments age, they require maintenance to ensure that all of their systems function in accordance with the manufacturer's specifications. Modern approved instruments measure time, mouth alcohol, breath volume, breath flow, radio frequency interference, ambient conditions, chemical interferents, and other values, and match them against internal and external standards. As time passes, systems and sensors get dirty or unstable, clock batteries weaken, and calibration drifts.

In R. v. St-Onge Lamoureux, the Supreme Court of Canada relied on a paper by Brian Hodgson, entitled The Validity of Evidential Breath Testing. Hodgson stated in that review article:

"Any scientific device or technique used to measure breath alcohol concentrations must address four fundamental issues in its design: accuracy, precision, reliability and specificity."

Hodgson defines "reliability" as follows:

"Reliability refers to the ability of the instrument to perform over time without any significant drift in accuracy and precision."


Watch the 5000EN video on this page. The Intoxilyzer instrument depicted  was once a "reliable" evidentiary breath instrument. However, it has not been properly maintained. Calibration of the internal standards has drifted over time. As with an aging automobile that has not been properly maintained, this instrument has become unreliable. The accuracy and precision of either its breath analysis system or its internal standards has drifted. It requires multiple start attempts to get it going. Like a car that won't start or a computer that has crashed, you need to keep trying to get it going. Over time and many start attempts, sometimes it passes and sometimes it fails its startup tests. Sometimes it starts after 2 tries, sometimes after 20, sometimes hours later, and sometimes not at all. Once it is finally going, however, it tends to "pass" (at least in terms of the screen messages and printouts at time of use) stand-alone diagnostics, stand-alone cal. checks, stand-alone breath tests, and internal standards. Watch the video to see an example of just how many times it takes to get the instrument going.

To be "reliable", an individual evidentiary instrument needs to be "accurate", "precise", and "specific", at every time and in every place. An instrument that was reliable many years ago at the factory may not be reliable now. An instrument that appeared accurate in a laboratory in controlled conditions, may not be reliable out-in-the-field in a police breath room or a R.I.D.E. mobile breath testing truck. An individual serial number production instrument may not match the accuracy, precision, and specificity of the prototype that was evaluated so many years ago.


Although, new instruments submitted for evaluation are not supposed to be prototypes, it is apparent from reading evaluations that: 1. they receive manufacturer re-calibration immediately before submission to the evaluation body and 2. that production models that start being shipped to police a year or two later after approval by the Minister, have different hardware and firmware. "Type" approval is very different from "verification" of an individual production instrument that has been shipped to Canada.

Model numbers sometimes change between evaluation (e.g. 5000 or 8000) and production (e.g. 5000C or 8000C).

The purpose of a breathalyzer is different from an automobile. A breathalyzer is a scientific and forensic measuring device. It does not simply "work" or "not work". We rely on a breathalyzer to measure guilt or innocence. Measurement of BAC for a forensic purposes is a quantitative analysis. Most defence lawyers need continuing education on the subject of quantitative analysis used for a forensic purpose. An "approved instrument" measures quantities, not simply a pass or fail (a screening device). If you don't understand this distinction you need to take a course.


If the Criminal Code, as amended, authorizes evidentiary searches to obtain a quantitative analysis for a forensic purpose by means of a machine that is not capable of a reliable quantitative analysis, then the Criminal Code violates Charter section 8. If alleged approved instruments, in a particular  jurisdiction, are, in fact, only screening devices (i.e. capable only of detecting above 80 or 100, rather than quantitating), then there is massive systemic failure that will result in innocent convictions.


Another aspect of "reliability" has to do with the "measuring interval" of the instrument. A prototype or out-in-the-field instrument may appear to be accurate and precise at 100 mg/100mls, but be unreliable below a "lower limit of quantitation" such as 80, 50, 30, 20, or 12 mg/100mls. To be "quantitative", a quantitative analysis must be reliable across the measurement range or interval of the instrument. This issue is particularly problematic in cases where the indicated BAC is in the 20 to 80 mg/100mls range. Statutory read backs such as section 320.31(4) (or searches that could result in a statutory read back)  may therefore be unconstitutional.

Constitutional litigation will be complex where the cause of the unconstitutionality is systemic, rather than the construction of the legislation. Defence lawyers need to work together collaboratively to build  good evidentiary records before raising  these issues.

Unlike an automobile, the purpose of an evidentiary breath testing instrument is not to simply get from one point to another, i.e. produce a result. A breathalyzer's purpose is to accurately, precisely, specifically, and reliably measure a whole variety of parameters associated with the prosecution of an excess blood alcohol criminal charge or a refusing / failing to provide an adequate breath sample criminal charge. The instrument does not simply work or not work. It measures for a forensic science purpose. Calibration of all measuring systems or exception thresholds (e.g. RFI, interferent, and ambient environmental conditions) must be in accordance with the manufacturer's specifications. A simple calibration check of ethyl alcohol calibration at 100 mg/100mls ONLY does not provide a complete control check for ethyl alcohol at other concentrations because calibration is a curve; it is not linear. A simple wet-bath or dry gas calibration check DOES NOT constitute a control check for all the other measuring systems or exception thresholds. That's why regular complete inspections and maintenance of breath instruments are so essential to the integrity of  breath testing in Canada. Transparency of documentation of such inspections and maintenance is essential to the constitutionality of the Parliamentary scheme - see R. v. St-Onge Lamoureux in the SCC.


The "approved instrument", the breathalyzer itself,  is not the only measuring device used in evidentiary breath testing in Canada. Accessory equipment is necessary too, and must be inspected and maintained to check calibration and thresholds for exception messages. Accessory equipment includes simulators and simulator thermometers. Transparency of documentation of such inspections and maintenance is also essential to the constitutionality of the legislative scheme (see R. c. Lopez in QC SC).

The failure of investigating authorities to recognize the forensic purpose behind quantitative analyses used in Court proceedings  has resulted in miscarriages of justice in Ontario. The Motherisk Inquiry  is a good example of a review of what can go wrong when authorities fail to recognize that most forensic analyses are quantitative rather than qualitative and fail to follow clear standard operating procedures. CFS scientists have acknowledged during cross-examination that pre-amendment Criminal Code sections 253(1)(b), 254 "approved instrument", 254(3)(a)(i), 258(1)(c), and 255.1 require quantitative analysis to determine concentration, rather than the qualitative analysis of a screening device. CFS scientists have also acknowledged that neither the Alcohol Test Committee nor the Centre of Forensic Science provide metrological supervision of police in their use of instruments out-in-the-field. It is respectfully submitted that if Ontario's approved instruments are not properly and transparently maintained and operated, under proper metrological supervision, so that they are capable of providing scientifically reliable quantitative analysis, then Parliament's breath testing schemes under both Bill C-2 and Bill C-46 are frustrated.  Parliament cannot have intended such an unreasonable and unconstitutional application of its scheme.


Access to the Blog is Restricted to Members of this Site contains a large number of resources for use by Canadian defence lawyers in defending charges of impaired driving, over 80, and refusal to blow. Under Bill C-46 we must pay a great deal of attention to the ambient fail systems and the control check systems of approved instruments. It is important that lawyers prepare for cross-examination of Qualified Technicians and government experts.


We have created online courses to help defence lawyers. Contact Stephen Biss for more information.




Please find below, a simple video explanation of the creation of the Intoxilyzer 8000C calibration curve at the factory or during re-calibration by the Canadian Authorized Service Centre. This video is an excerpt from one of our online courses for defence lawyers. The calibration of an instrument out-in-the-field is only as good as the last creation of a calibration curve saved within the software of the individual instrument. A saved calibration curve is unique to each individual instrument and each re-calibration of that individual instrument. It is not the case that one calibration curve exists for all instruments of an approved type. An understanding of "calibration curve" is fundamental to any defence lawyer's application for disclosure and any challenge to the reliability of an instrument. Before you call evidence or conduct a cross-examination  on issues of disclosure or reliability, consider taking an online course or doing research about the creation of the calibration curve.

Justice Watt in R. v. Stipo at 109:

"…But the material issue in each case had nothing to do with the instrument’s performance on other occasions. The material issue in those cases was how the approved instrument worked when it measured Jackson’s and Gubbins’ blood alcohol levels.”


Reliability of an instrument at time of use is a function, among other things, of its last calibration curve, probably last established, during annual or other maintenance. The connection between annual or other maintenance and the creation of the calibration curve, is essential to an understanding of and proper application of Canadian case law such as R. v. Stipo, R. v. Vallentgoed, R. v. Gubbins, R. v. Jackson, and section 320.34 of the amended Criminal Code.

With the greatest of respect to those who hold a contrary view:


1. two tests at least 15 minutes apart with good agreement,


2. single data point cal. checks  at 100 ± 10 mg/100mls, and

3. automatic self-diagnostics tests (the checks and balances argument)

DO NOT exclude the real possibility that the instrument has, at time of use, an improperly fitting calibration curve. Two tests of 53 and 57 mg/100mls may both be inaccurate. The instrument may have dirt or circuitry that has degraded over time that requires re-calibration - the creation of a better and proper calibration curve. The last creation of a calibration curve may have been done negligently using unreliable alcohol standards (traceability) during annual maintenance. The instrument may have lost, to use Hodgson's words, its ability "to perform over time, without any significant drift in accuracy and precision" at points in the measuring interval other than 100 mg/100mls. The instrument may be "accurate" at 100 mg/100mls but unreliable at 50 or 150 mg/100 mls. The measurement result may no longer be traceable, as required by the federal Weights and Measures Act, to the international standards for kilogram and litre.

Continuing education on forensic measurement, including metrological concepts such as "calibration curve" and "traceability", is essential for defence lawyers.

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