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If you are arrested for OVI, the police will ask you to blow into a Breathalyzer at the station. 

Breathalyzer Instruments

There are three Breathalyzer Instruments approved by the State of Ohio under the Ohio Administrative Code (OAC) 3701-53-02. They are:

  • BAC Datamaster
  • Intoxilyzer model 5000 series
  • Intoxilyzer 8000

How Do Breathalyzers Work?

A Breathalyzer does not measure alcohol in a person's breath. It actually attempts to filter out other molecules in a person's breath. The Intoxilyzer 8000 uses the scientific principle of Infrared Absorption to analyze the breath sample. The infrared light source is a pulsed infrared light. Infrared light is not visible to the human eye. It is similar to the light from a TV remote.

A person blows into the machine. The machine produces a specific amount of infrared light, which passes through the person's breath to a sensor. If a person has alcohol in their breath, then a certain amount of infrared light will not be detected by the sensor. This is because the alcohol molecules absorb a known amount of the infrared light. 

In other words, the machine is calibrated so that a certain amount of infrared light is detected by the sensor, but when a person's breath has alcohol in it, then those alcohol molecules decrease the infrared light that reaches the sensor. This allows the machine to measure the person's blood alcohol level.

Are Breathalyzers Accurate?

To an extent they are, however there are several things that cause the Breathalyzer to give a false measurement. Per Ohio Administrative Code (OAC) 3701-53-01 through 3701-53-10, certain things must be done to ensure a Breathalyzer is accurate. In addition, the Breathalyzer must be properly used by the officer. Further, the officer has to provide a person arrested for an OVI certain instructions. Below is a list of things that are reviewed by Fogt Law Office in a Breathalyzer case. We will look at a couple in detail.

  • Was the Breathalyzer calibrated every seven days with no more than 192 hours between checks?
  • When was the last time it was serviced or was repaired?
  • Is the machine new or old?
  • How was the machine tested for Radio Frequency Interference (RFI) sensitivity?
  • Was the machine tested with a solution that was not expired and had not been opened for longer than three months?
  • Was the person observed uninterrupted for 20 minutes to ensure that mints, gum, or anything else was not placed in the mouth that could prevent an accurate measurement from the Breathalyzer?

Breathalyzer-How To

Most officers instruct those arrested for OVI to take a deep breath and to blow. As a person is blowing, officers typically tell them to "Keep blowing, blow harder!" This is incorrect and will cause the machine to give an inflated number indicating that a person is intoxicated. This method causes a large volume of non-alveolar air to enter the machine.

According to page 2 of the BAC Datamaster Supervisor Guide, it is best to have a smaller volume of alveolar air because the testing will more accurate. "The best simply to tell the subject to take a normal or moderate breath and to blow until he is told to stop...Instructing the subject to take a deep breath is not helpful, and may be detrimental as it simply means there is more air to be expelled before alveolar is reached. Never instruct a subject to blow hard as this can cause...the instrument reading to be slightly unstable...Remember, it concentration uniformity, not volume, that is necessary for a good test." (page 3).

The DataMaster Basic Operator Guide (page 6) states "Do not tell the subject to blow hard..."

A person should only blow into Breathalyzer for approximately 5 to 7 seconds at a steady rate. 

It is almost always best NEVER to blow.

Breathalyzer Time-Frame

The police cannot conduct a breath test more than two hours after the time of the violation (not the arrest). This is especially important in cases involving auto accidents, since the officer was not at the scene at the time of the actual violation.

Radio Frequency Interference (RFI)

Breathalyzer manuals warn that that their machines are susceptible to RFI. Electromagnetic interference that may obstruct, interrupt, or degrade the ability of the instrument to measure the presence of alcohol. This can be caused by electronic devices such as:

  • Police radio
  • Cell phones
  • Computers

Health Conditions

Certain health conditions and other related things can cause an unreliable Breathalyzer measurement such as:

  • GERD
  • Diabetes
  • Acid reflux
  • Dentures
  • Elevated body temperature
  • Ingestion of cold medicine or cough syrup

Fogt Law Can Help You

Attorney Fogt understands how Breathalyzers work and how best to challenge them to obtain the best result for his Clients. He is also certified in the NHTSA manual just like the police and has 104 hours of Continuing Legal Education classes on OVI alone. 

Attorney Fogt practices in Federal Court and all over the State of Ohio including, but not limited to Montgomery County, Greene County, Miami County, Warren County, Hamilton County, Clark County, Franklin County. Attorney Fogt also practices in Kettering, Miamisburg, Dayton, Xenia, Fairborn, Springboro, Clark, and Lebanon Municipal Courts as well as others. 


Fogt Law Office is a BBB Accredited Lawyer in Dayton, OH