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DUI Breath Devices: The Draeger Alcotest 7510

December 29, 2017

This is the next installment in a series of Dan's Den articles about the various breath testing devices that are used in California DUI case. In this article, I will discuss the Draeger Alcotest 7510. This device is currently used in more counties than any other in the State of California.

The handheld 7510 runs on fuel cell technology, which makes the 7510 susceptible to all the same issues that other fuel cell devices have (and which have been discussed in previous Dan's Den articles). The 7510 claims to be the first handheld breathalyzer capable of mouth alcohol detection using a device called a “piezo-electric” activator. However, there is not a single published study, peer reviewed or otherwise, that demonstrates that the “piezo-electric activator” is effective for mouth alcohol detection. Additionally, the 7510 needs to be equipped with this optional feature, and the feature needs to be “employed” during the subject test. The model currently used by the California Department of Justice (DOJ") does not appear to have this optional feature, as it is not described in the DOJ manual and there is no provision in the training manuals that discusses the use of this optional feature.

The 7510 manual used by the DOJ is available online. The manual lays out the respective duties of the operator and laboratory. The precautionary checklist, calibration and accuracy check procedures are readily available online as well. The 7510 is not a significant upgrade from the 7410 and all principles of operation and most of the features are shared in common with the exception of typical data handling upgrades due to advances in digital technology. The fuel cell is identical. In all likelihood the 7510 model was merely a stopgap replacement for the 7410 in light of the defect in the 7410 which essentially lets the operator intentionally manipulate the result.

The most obvious potential benefit of the handheld nature of this machine is that it can be used at roadside, which is generally the practice in California jurisdictions using this machine. Another optional feature for the 7510 is a GPS module, again not listed in the DOJ manual.
The 7510 has upgraded data processing and storage capabilities and therefore more information than is contained on the breath ticket should be available for inspection by a DUI defense attorney. The data from the mobile unit can be transferred to a central PC database via modem or Ethernet. This transfer of data occurs at least every 10 days according to DOJ procedures. The information is stored with the Breath Alcohol Analysis Records section at DOJ. The 7510 also has a calibration/accuracy check lock-out period, if exceeded will not permit additional testing.

The DOJ conducts periodic determination of accuracy checks on the 7510 (and the remaining 7410 units) in intervals required by Title 17 by using an “approved” Dry Gas Calibration Ethanol Standard. The Ethanol/Gas standards are acquired in a lot of may dry canisters. The lot will be accompanied by a certificate of analysis, presumably from a certified provider of dry gas alcohol standard solutions. The level commonly used by the DOJ is .10%. The certificate of analysis verifies the level of ethanol in the gas can at the time it is tested. The certificate of analysis will also contain information regarding the uncertainty associated with the measurement of ethanol in the container, as well as the limitations of that uncertainty including the conditions placed on the representation regarding the uncertainty, including an expiration date for the dry gas standard. The DOJ then will test at least one of the gas cans from the lot to verify their alcohol content. The verified content will be assumed for all the gas cans in the lot even though they have not been tested. All verification tests are done in Sacramento. The remainder of the lot is shipped out the various DOJ locations. DOJ uses an Alcotest 7110 to conduct the verification checks on the dry gas tanks. A Guth wet-bath simulator is used to conduct the verification checks on the dry gas tanks themselves. Part of the process involves using a water vapor correction factor. Additionally the ambient atmospheric pressure feature of the Alcotest 7110 is used to calculate the resulting pressure correction factor.

A potentially serious flaw exists in the DOJ calibration/verification procedures, which is true for most forensic lab breath procedures. This flaw involves the use of a known value for accuracy checks based on the anticipated value as opposed to the real value of the alcohol content in the dry or wet simulator. For example, the “known” value used for the gas calibrator (which, as noted above, came from the single verified tank for the lot; the actual tank is never verified) may be .10; however the actual “known” value from the verification checks might be .098. So if the Alcotest 7510 machine reads .109 on the accuracy checks, it would be acceptable within the acceptable range of +/− .01 as required under Title 17 and DOJ policy. Because the breath machine was being told that .098 was actually .10, the machine would not flag at .109 since it did not recognize that the result was registering outside of the .01 +/- tolerance.

As you can see, the technology, maintenance and measurements of breath machines is quite complex. At Chambers Law Firm, we understand these complexities and know how to exploit weaknesses that allow us to build a solid defense in your DUI case. Call us today for a free consultation.

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