Getting to Know Washington’s New DUI Breathalyzer: The German Made Dräger Alcotest 9510

Washington State’s new DUI breathalyzer is called the Alcotest 9510, which is manufactured by a German company called Dräger Industries.

In 2005, the Washington State Patrol wanted to replace its aging fleet of DataMaster and DataMaster CDM DUI breathalyzer machines which had been in service since 1984. After DataMaster manufacturer National Patent Analytical Systems, announced that they would be no longer producing these machines, the WSP decided to purchase the Dräger’s Alcotest 9510and eventually phase it in as the state-wide standard breath testing device.

Like all breath testing machines, the Alcotest is a device which is used to measure a drunk driving suspect’s breath alcohol content. The Alcotest 9510 does this by actually taking two separate breath samples from each suspect and then sends those samples one at a time through the machine’s two testing chambers. The first chamber analyzes alcohol contained in the breath sample by using a chemical reaction from an electrochemical cell (referred to as the EC result). Next the machine sends the same breath sample into a second chamber where it is tested using infrared lights called infrared spectroscopy (referred to as the IR result). Once IR result is completed the machine purges itself of the air sample and gets ready for the second breath sample from the suspect.

This testing process ultimately results in 4 BAC readings – 2 EC results and 2 IR results. This system which uses two separate and accurate technologies to test the same breath sample is intended to provide the highest level of accuracy and legal integrity.

In order for the machine to give a successful final BAC, all 4 readings must be within a certain tolerance of one another to be considered a “true” reading. This is done by plugging the numbers into an algorithm created by the manufacturer. However, Washington State Law gives the defendant the benefit of the doubt by taking the lowest of the 4 readings and rounding down to the second decimal place.

For example, if your readings are 0.148, 0.139 0.145and 0.150, then your reading final BAC legal reading would be 0.139%.Also, all four test results (IR and EC from each of the two breath samples) must be within ± 10% of the mean of all four test results.

It is important to note that there are many more requirements that must be followed in order to achieve an accurate and true reading. In order for the Alcotest to receive and acceptable breath sample, the suspect must meet certain requirements such as a minimum air volume and blowing duration. If the sample is too small the machine cannot test it and you could be charged with Refusal to Submit to a Breath Test if the police are unable to obtain any readings.

Moreover, the mouth piece must be changed between each breath to minimize the effects of any residual alcohol. There must also be a two-minute lock out between each breath sample to ensure the machine has enough time to purge the last breath sample before taking a new one.
Other requirements include that the police officers must observe the suspect continuously and uninterrupted for 15 minutes directly prior to blowing into the machine as well making sure all radio devices, including cell phones are removed from the testing room. Also, all officers using the Dräger’s Alcotest 9510 must receive specialized certification and recurrent training in order for the breath test results to be admissible in court.

Note: In the DataMaster DUI Breathalyzer and DataMaster CDM, there was a “wet bath” external sample chamber used. However, the Drager uses two ethanol dry gas cylinders mounted on the rear of the instrument rather than the wet external sample. These are secured with a technician key and cannot be altered by the operator.