BAC DataMaster Breathalyzer Information

Manufactured by National Patent Analytical Systems of Mansfield, OH, the BAC DataMaster is the second most widely used breath testing unit used by law enforcement in the United States. Based on infrared spectrometry, the BAC DataMaster is a desktop unit (versus a hand-held or portable "field unit") used to calculate the Blood Alcohol Content (BAC) of an individual suspected of Driving While Intoxicated (DWI) or Driving Under the Influence (DUI).

Like most breath testing units, a test subject is required to provide a breath sample by blowing into a mouthpiece and tube connected to the BAC DataMaster. The BAC DataMaster begins sampling the breath at a rate of four times per second to verify that the test subject is providing a valid sample. A valid sample is one in which the test subject blows a consistent and deep breath in order to obtain breath from the lower levels of the lungs where alcohol\ethanol concentrations are at their highest. The longer the subject blows, the higher the alcohol content of the tested sample. The intent is to obtain a sample in which the highest Blood Alcohol Content (BAC) can be obtained. While subjects should initially be informed to take a deep breath and blow long and deep, many subjects are informed that they need to blow harder or deeper on the second test. This is often why a subject's first and second Blood Alcohol Level (BAL) test results vary so greatly.

Between the first and second breath test to determine Blood Alcohol Content (BAC), the BAC DataMaster conducts a "control" test on a solution of water and alcohol in a 1:10 ratio. The results should register between .90 and .110 for the control. This indicates that the BAC DataMaster unit appears to be functioning properly and becomes part of the evidence ticket.

While many states use the BAC DataMaster to determine Blood Alcohol Level (BAL) and to provide evidence in the prosecution of an individual suspected of Driving While Intoxicated (DWI) or Driving Under the Influence (DUI), it is accepted in the scientific community that this type of device is not the most accurate method of determining the alcohol content in a breath sample.

In fact, there are numerous factors which can contribute to a "false positive" or incorrectly high or low Blood Alcohol Content (BAC) reading in these types of devices. While the manufacturer claims that sufficient safe-guards are built into the device to eliminate these factors, they are unwilling to reveal the formula and equations used by the machine to eliminate error.