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BAC Instruments and SAS in Ontario

Guth 34C Simulator

Manufactured by: Guth Industries

Used by: All Ontario Police services

External Link to Manufacturer

External Link to Local Distributor

This Guth 34C calibration instrument, used together with a Standard Alcohol Solution (SAS), simulates the breath of a so-called average human being with an average breath temperature of 34.0° C. Human breath temperatures may vary.

SAS's used in Ontario by police (see SAS Laboratoire Atlas, SAS Alcohol Countermeasures, SAS Bodycote, SAS Calwave) are generally designed to produce a target "cal. check" of 100 mg/100 ml or .100 on the "cal. check" phase of the breath test sequence on the Intoxilyzer 5000C. Look at the "cal. check" notations on your Intoxilyzer Test Record. If, for example, the "cal. check" shows .093 then this means that the Intoxilyzer was interpreting a known SAS sample of 100 mg/100 ml as a reading of 93 mg/100 ml . If, for example, the "cal. check" shows .105 then this means that the Intoxilyzer was interpreting a known SAS sample simulating 100 mg/100 ml as a reading of 105 mg/100 ml . The Alcohol Test Committee Standards allow an error of plus or minus 10 mg/100 ml. If a "cal.check" produces a reading of more than .110 or 110 mg/100ml or less than .90 or 90 mg/100 ml then the test is unacceptable.

The above acceptable margin of error assumes that the SAS has the correct concentration and that the simulator is operating at 34.0° C. The Alcohol Test Committee also has acceptable ranges of error for the SAS concentration and the simulator temperature. Unacceptable temperatures for the simulator are less than 33.8° C or more than 34.2° C. Unacceptable temperatures or unacceptable SAS concentrations render "cal. checks" within the plus or minus 10 mg meaningless.

The simulator must be capable of holding its temperature constant throughout the breath sampling sequence. According to factory specifications this instrument when properly inspected and maintained holds its set temperature (34.0° C) at plus or minus .05° C.

A simulator thermometer (usually a NIST certified mercury thermometer) is used by the breath tech to verify the temperature. The breath tech must look closely at the thermometer during the breath test sequence and accurately record the temperature indicated on the thermometer. Watch the video carefully to see if the breath tech looked carefully at the simulator thermometer.

Obviously a reading by the breath tech of the thermometer at 33.8°, 33.9°, 34.0°, 34.1° or 34.2° C.  is meaningless unless the simulator thermometer is accurate. We are all familiar with the phenomenon of gaps forming in mercury when a thermometer is dropped or subjected to unusual conditions. Unless the breath tech and his or her colleagues have taken steps to ensure that the thermometer is safeguarded from mercury gaps and regularly inspected then one cannot assume that the recorded reading taken from the thermometer is accurate.

The Alcohol Test Committee requires that simulators and simulator thermometers be inspected and maintained at least once per year to ensure that they are as accurate as possible. Serial numbers of simulators and simulator thermometers should be noted. Maintenance logs should be kept respecting each serial numbered simulator and each serial-numbered simulator thermometer. Mercury gap repairs should be documented in the officer's notes or thermometer maintenance log.

"A maintenance log shall be kept for each Approved Instrument, Approved Screening Device and accessory equipment in active use in the program. Logs should include the results of all inspections, documentation of the maintenance history including records of parts replaced and approved modifications to hardware or software."

It is respectfully submitted that in the absense of strict compliance with Alcohol Test Committee standards, "cal. checks" are meaningless and not in compliance with the spirit and intent of Criminal Code of Canada section 258(1)(g).



Click on Photo to Enlarge

simulatoropp.jpg (57307 bytes) Port Credit OPP Simulator 
(showing original calibration with no annual re-calibration)
Enlarge photo and Note the dates. Photo taken on April 27, 2001. 

Watch for temperatures above 34.2° C or below 33.8° C.

Unfortunately it appears that many police services are not bothering to recalibrate these instruments at least once a year. Note the calibration date information on the Port Credit OPP simulator. The Alcohol Test Committee standards require:

"The Program Director shall ensure that accessory equipment necessary for the proper operation of Approved Instruments and Approved Screening Devices (e.g. simulators, equilibrators) is periodically inspected to determine that such equipment continues to meet the manufacturer's specifications. The interval between such inspections shall not exceed one year."

Police services should replace old units with current models with current warranty or strictly adhere to regular maintenance protocols set by the Alcohol Test Committee. In the meantime, breath techs will be closely cross-examined as to the accuracy of their simulator temperature recordings. They may not be able to successfully withstand that cross-examination if there is a possibility that the thermometer is unreliable and hasn't been checked. This has become a serious problem for the authorities in the State of Washington, see State of Washington v. Leo Mitchell et al..


Please see www.impaired-driving.com for more recent information on approved instruments and accessory equipment used in Ontario, Canada.

Warning: This is NOT a government web site.  

Alcohol Test Committee Standards    Edit







This site is designed to encourage fair professional discussion among police officers,  lawyers, toxicologists, and judges respecting the appropriate use of these instruments. Please report any inappropriate or unfair comments forthwith to biss@lawyers.ca.
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 are "approved instruments" in Canada.
Alcotest® is a registered trademark of Draeger Safety, Inc. The Alcotest® 7410 GLC is an "approved screening device" in Canada.


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  WARNING: All information contained herein is provided for the purpose of providing basic information 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: This is NOT a government web site.