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Dräger Alcotest 9510: Washingtons DUI Breathalyzer

Washington State’s now uses the Alcotest 9510 for DUI breathalyzer testing.

In 2005, the Washington State Patrol wanted to replace its aging fleet of breathalyzer machines. The DataMaster and DataMaster CDM had been in service since 1984. DataMaster manufacturer National Patent Analytical Systems, announced that they would be no longer producing these machines. Washington State police began adopting the Dräger’s Alcotest 9510.

The Alcotest is a device measures a drunk driving suspect’s breath alcohol content. The Alcotest 9510 takes two separate breath samples from each suspect. It 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. It uses 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. This test uses infrared lights called infrared spectroscopy (referred to as the IR result). The machine purges itself of the air sample and gets ready for the second breath sample from the suspect.

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

For a “true” result all 4 readings must be within a certain tolerance of one another. This is determined by an algorithm created by the manufacturer. Washington State Law gives the defendant the benefit of the doubt. It takes the lowest of the 4 readings and rounds 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%. 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.

Some requirements include:

The minimum air volume and blowing duration. If a sample is too small the machine cannot test it. This can result in a charge of Refusal to Submit to a Breath Test if the police are unable to obtain any readings.

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. This ensures the machine has enough time to purge the last breath sample before taking a new one.

The police officers must observe the suspect continuously and uninterrupted for 15 minutes directly before blowing into the machine.

All radio devices, including cell phones must be removed from the testing room.

All officers using the Dräger’s Alcotest 9510 must receive specialized certification and recurrent training. This is required for a breath test result to be admitted in court.

Additional Notes:

The DataMaster DUI Breathalyzer and DataMaster CDM, used a “wet bath” external sample chamber. 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.

Facing DUI/DWI charge?

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