How Breath Testing Works

In Florida, a breath test instrument is an evidential machine used to measure, calculate, and record the breath alcohol level of a Florida DUI suspect.  The most common instrument used in Florida is the ‘Intoxilyzer 8000.’

The Intoxilyzer 8000 is an infrared analyzer manufactured by CMI, Inc., based on Owensboro, Kentucky. Broadly speaking, the instrument measures the amount of infrared light absorbed by ethyl alcohol as contained in a breath sample provided by a DUI suspect.  Since the concentration of the alcohol in the alveolar air released from a person’s lungs is directly related to the concentration of the alcohol in the blood, a measure of breath alcohol level will indicate whether a person is over the legal limit.

The Intoxilyzer 8000 analyzes a person’s breath on the basis of infrared absorption.  A lamp contained within the instrument generates an infrared beam, which is passed through the subject’s breath sample. Since ethyl alcohol absorbs infrared wavelengths at a 3.39 to 3.48 micron range, absorption of wavelengths at this range will indicate that the subject has alcohol in his or her system. The amount of infrared light absorption at that particular wavelength can then be used to determine how much ethyl alcohol is in the subject’s system.

One of the key problems with the Intoxilyzer 8000 is that the instrument does not measure specifically for ethyl alcohol.  Any organic molecule within the so-called “methyl” group of organic compounds (including acetone, methyl alcohol, diethyl ether, acetaldehyde) will absorb infrared light in the same manner as ethyl alcohol.

If these compounds or molecules are present in the subject’s system, they will grouped simply as “ethyl alcohol.”  This can lead to unreliable blood alcohol content measurements. Methyl group molecules can be present in a person’s breath for a variety of reasons aside from of consumption of alcoholic beverages. Some occur naturally in the human breath, while others can be present by inhaling gasoline fumes, and fumes from glue, paint, lacquer thinner, chemical cleaners, and even smells from your car.

Legal Grounds to Request a Breath Test

Under Florida’s Implied Consent Law, a breath test must be incidental to a lawful arrest and administered at the request of a law enforcement officer who has reasonable cause to believe such person was driving or was in actual physical control of the motor vehicle within this state while under the influence of alcoholic beverages.

Operation Procedures- Florida

The procedures governing the operation, inspection, and maintenance of Intoxilyzer 8000’s in Florida are contained in Chapter 11D-8 of the Florida Administrative Code.

Compliance with the breath testing code provisions is critical, as they are designed to ensure the accuracy of breath test results. The standard for a valid and admissible breath result is “substantial compliance.”

Shown below is a reproduction of “Form 37,” which outlines the step-by-step procedures that an operator must follow in administering a test with the Intoxilyzer 8000.

FORM 37: OPERATIONAL PROCEDURES- INTOXILYZER 8000

1.  All results are reported to three decimal places in g/210L.  The instrument must display READY MODE prior to beginning the breath test.  Push the START TEST button to begin the breath test:

    • Enter Breath Test Operator last name, first name and middle initial at USER prompts.
    • DATE/TIME.  Verify the displayed date and time.  Change if necessary.  Press ENTER.
    • LAST AGENCY INSPECTION DATE.  Verify the agency inspection date displayed.  Press ENTER.
    • CYLINDER LOT#.  Verify the dry gas standard cylinder lot number.  Change if necessary.  Press ENTER.
    • EXPIRATION DATE.  Verify the dry gas standard cylinder expiration date.  Change if necessary.  Press ENTER.
    • OBSERVATION PERIOD BEGAN.  Enter the time the observation period began (at least 20 minutes).
    • SWIPE DL OR PRESS ENTER.  Either swipe the subject’s driver license or identification card or press ENTER.  Enter applicable information as prompted.
    • DIAGNOSTICS CHECK.  The result must be OK.
    • AIR BLANK.  The result must be 0.000.
    • CONTROL TEST.  The result must be between 0.075 and 0.085, inclusive.
    • AIR BLANK.  The result must be 0.000.
    • PROVIDE SAMPLE NOW.  Have the subject provide a breath sample into the instrument.
    • AIR BLANK.  The result must be 0.000.
    • PLEASE WAIT.  The instrument will countdown the time remaining for the wait period.
    • AIR BLANK.  The result must be 0.000.
    • PROVIDE SAMPLE NOW.  Have the subject provide a breath sample into the instrument.
    • AIR BLANK.   The result must be 0.000.

Note:    If there is no 0.020 g/210L agreement between first and second breath samples, the instrument will automatically request a third breath sample as follows:

    • PLEASE WAIT.  The instrument will countdown the time remaining for the wait period.
    • AIR BLANK.  The result must be 0.000.
    • PROVIDE SAMPLE NOW.  Have the subject provide a breath sample into the instrument.
    • AIR BLANK.  The result must be 0.000.
    • CONTROL TEST.  The result must be between 0.075 and 0.085, inclusive.
    • AIR BLANK.  The result must be 0.000.
    • DIAGNOSTICS CHECK.  The result must be OK.

2.  If an external printer is used, FDLE/ATP Form 38 – Breath Alcohol Test Affidavit – Intoxilyzer 8000 will be automatically printed containing all the results.  If no external printer is used, a printout slip containing all the results will be automatically printed.

3.  Complete FDLE/ATP Form 38 – Breath Alcohol Test Affidavit – Intoxilyzer 8000.

Breath Instrument Inspections- Florida

For results to be admissible at trial, all Intoxilyzer 8000 breath instruments in use in Florida must be inspected monthly by police agencies and once yearly by the Florida Department of Law Enforcement.

The inspection procedures for police agencies are outlined in Form 39, while the procedures for Department inspections are contained in Form 36.  Form 39 is reproduced below in its entirety.

FORM 39: AGENCY INSPECTION PROCEDURES – INTOXILYZER 8000

1.  Prepare at least two simulators for use and allow them to warm up for at least thirty minutes prior to the first analysis.  When changing solutions, allow the new solution to warm up for at least ten minutes after the heater light turns off for the first time.  Ensure that each simulator maintains an air leak resistant seal and an operational temperature of 34 C (+/- 0.2 C).

2.  Only distilled or deionized water must be used for the Alcohol Free Test and the Interferent Detect Test.  Class A glassware must be used when measuring solutions.

3.  Only approved and non-expired alcohol reference solution and non-expired dry gas standard from an approved source must be used during the applicable portions of the inspection.

4.  Press ESC twice to access the main menu.  Enter Agency Inspector last name, first name and middle initial at USER prompts.  Press the 2 key to access the Agency Inspector menu.  Enter password.  Scroll to Inspection Test and press ENTER.  Enter Agency Inspector last name, first name and middle initial at INSPECTOR prompts.

5.  All results are reported to three decimal places in g/210L.  The result must be 0.000 for each air blank.  The instrument will abort the inspection process if the air blank result is not 0.000.  If any test is out of compliance the instrument will prompt the Agency Inspector to REPEAT (Y/N) the test.  Each test may only be repeated once.  If a test must be repeated, the REASON must be entered when prompted and recorded in the Remarks section of FDLE/ATP Form 40 Agency Inspection Report – Intoxilyzer 8000.

    • Verify DATE.  Adjust if necessary.  Press ENTER.  Verify TIME.  Adjust if necessary. Press ENTER.
    • DIAGNOSTIC CHECK (Pre-Inspection).  Press ENTER.  The result must be OK for each diagnostic check.  If any diagnostic check result is not OK, the instrument will abort the inspection process.
    • NUMBER OF SIMULATORS USED.  Enter the number of simulators used during the inspection.
    • ALCOHOL FREE SUBJECT/MOUTH ALCOHOL TEST.  Press ENTER.  When PROVIDE SAMPLE NOW is displayed, introduce an alcohol-free breath sample into the instrument.  The result must be 0.000.  Rinse mouth with mouth alcohol solution. When PROVIDE SAMPLE NOW is again displayed introduce a breath sample into the instrument.  The result must be SLOPE NOT MET.
    • ALCOHOL FREE TEST.  Attach a simulator containing 500 mL distilled or deionized water to the instrument.  Press ENTER.  Conduct three (3) analyses.  The result must be 0.000 for each analysis.
    • INTERFERENT DETECT TEST.  Attach a simulator containing 3 mL of acetone stock solution and 500 mL distilled or deionized water to the instrument.  Press ENTER. Conduct three (3) analyses.  The result must be INTERFERENT DETECT for each analysis.
    • 0.05 g/210L TEST.  Attach a simulator containing 0.05 g/210L alcohol reference solution to the instrument.  Press ENTER.  Enter the lot number and expiration date of the alcohol reference solution used.  Conduct three (3) analyses.  The result of each analysis must be within the acceptable range.
    • 0.08 g/210L TEST.  Attach a simulator containing 0.08 g/210L alcohol reference solution to the instrument.  Press ENTER.   Enter the lot number and expiration date of the alcohol reference solution used.  Conduct three (3) analyses.  The result of each analysis must be within the acceptable range.
    • 0.20 g/210L TEST.  Attach a simulator containing 0.20 g/210L alcohol reference solution to the instrument.  Press ENTER.  Enter the lot number and expiration date of the alcohol reference solution used.  Conduct three (3) analyses.  The result of each analysis must be within the acceptable range.
    • 0.08 g/210L DRY GAS STANDARD TEST.  Attach a cylinder containing 0.08 g/210L dry gas standard to the instrument.  Press ENTER.  Enter the lot number and expiration date of the dry gas standard used.  Conduct three (3) analyses.  The result of each analysis must be within the acceptable range.
    • DIAGNOSTIC CHECK (Post-Inspection).  Press ENTER.  The result must be OK for each diagnostic check.  If any diagnostic check result is not OK, the instrument will abort the inspection process.
    • REVIEW REMARKS.  Enter Y/N.
    • IN COMPLIANCE.  Enter Y/N to state whether the instrument complies or does not comply with the requirements of Chapter 11D-8, FAC.  If the instrument does not comply with Chapter 11D-8, FAC, remove the instrument from service and notify the Department Inspector.

6.  The results of the Agency Inspection must be recorded on FDLE/ATP Form 40 Agency Inspection Report – Intoxilyzer 8000.

For regulatory and administrative purposes only, the results of the agency inspection must be made electronically available to the Department within five (5) days of completing the inspection.

Breath Test Defenses- Florida

There are multiple defenses that may be used in a Florida DUI case to question the validity of a breath test result, or to challenge the admissibility of those results. Some of the more common defenses include the following:

  • Were the inspections of the breath machine conducted in substantial compliance with the Florida Administrative Code?
  • Did the actual operation of breath machine substantially comply with the Florida Administrative Code?
  • Is the breath test operator legally qualified to administer a breath test and, if so, what is the nature of those qualifications?
  • How familiar is the breath test technician with the materials contained within his or her training manual?
  • How knowledgeable is the operator about how breath machines work?
  • Has the operator had any follow up training?
  • Did the operator comply with the 20 minute observation period?
  • Was there a 0.020 g/210L agreement between first and second breath samples. If not, was a third breath sample requested?
  • Were the subject’s breath samples taken within 15 minutes of each other?
  • Did the breath  test subject have anything in his or her mouth that may have affected the breath result?  Was this issue even addressed?
  • Was mouth alcohol (such as residue from antiseptic mouth rinse) present in the subject, or did the subject wear dentures or adhesives so as to affect the results?
  • Were the breath results affected by reflux or regurgitation?
  • Did the operator comply with procedures governing diagnostic checks and control tests?
  • Were monthly and yearly inspections conducted on the breath machine, as required by the Florida Administrative Code?  If so, did these inspections reveal problems with the machine?
  • If the machine exhibited malfunctions or irregularities (i.e. non-compliance) during the inspection process, were proper steps followed to have the machine examined?
  • If, during inspection, the instrument did not comply with Chapter 11D-8, FAC, was the breath machine removed from service and the Florida Department of Law Enforcement notified of the non-compliance?
  • Are the breath results inconsistent with the observations made of the Defendant during the traffic stop and during field sobriety exercises?
  • Did the officer check to see if the machine was properly calibrated on the day the test was administered?
  • Can the breath test operator say that the results displayed by the breath machine are specific for beverage alcohol?  [no].
  • Does the breath test operator have any independent knowledge of whether mechanical functions occurred with the breath machine? Was there ever an inspection of the quartz lamp, lenses, filter wheel, photocell, or microprocessor?
  • Did the arresting officer have sufficient grounds to request a breath sample from the defendant in the first place?
  • Was implied consent read to the defendant?