Blood-Alcohol Level Testing Equipment, Faults and Limitations

The Service Guide then continues with a list of what it terms "functional errors"; that is, malfunctions for which there are no error messages to alert the operator:

• No Breath Tube Heat

• Blinking Stops, But No Sample

• Instrument Samples Early, By Itself

• Blinking Does Not Stop When Instrument is Blown Into

• Supervisor Buttons Don't Function

• Difficult or Impossible to Blow Into Instrument

• Improper Operation of Pump

• No Display

• "Not Calibrated"

• Printer Runs Continuously

• MTR Button Doesn't Function

The Operator's Manual adds a few more ways the BAC Verifier/Datamaster can malfunction:

• Invalid Sample (the manual reads "mouth alcohol is being detected, subject is not providing a proper sample, or the instrument is out of adjustment"—but does not indicate which )

• RFI

• Calibration Error—Fatal Systems Error

These, the manuals stress, are only the more common sources of error possible with the Verifier/Datamaster. The Service Guide adds the following interesting comment: "If your instrument exhibits a symptom that is not identified in this guide, please notify us so that we may update our symptom information library" (emphasis added). This for two reasons:

1. There is an entire library of things that can go wrong with this machine!

2. The manufacturers are not even aware of some things that can go wrong: They are soliciting information about newly discovered defects for their presumably ever-growing library. What malfunction will be discovered next!

It is also interesting to note that the Verifier/Datamaster has an internal self-checking diagnostic system, run by its computer. Of course, garbage in equals garbage out, but in theory such a readily available diagnostic check might detect malfunctions in the machine. Yet these checks are performed only periodically and not before each test. Despite the fact that such a check would detect, for example, whether the critical temperature of the sample chamber is 50 degrees, such a check is almost never done immediately before or after a DUI suspect is tested.

There are more problems that are associated with any breath testing machine that use infrared absorption. These are covered in further detail here: Breathalyzer Tests.

Infrared Analyzer
An explanation of the basic design of an infrared analyzing machine which is used to measure breath alcohol concentrations.

Alcohol and the Human Body
Very general discussion of the physiological effects of ethanol.

The Drunk Driving Law Center
Megasite with discussion and links concerning blood alcohol concentration and blood and breath alcohol analysis.

The Science of Breath Testing
Scholarly discussion of the physiological basis for breath alcohol testing, from a professor of pharmacology.

Breath Testing Machine
Links to information that is related to breath testing and the use of breathalyzers.