What Does Calibration Mean?
Calibration, in the contest of breath alcohol testing, is the process in which the breath alcohol machine is configured so that all tests are completed within an acceptable range. Calibration is generally completed by comparing the machine results after running a test sample with a known alcohol content. Calibration is ensuring the machine measures alcohol content correctly when compared to a standard measure.
WorkplaceTesting Explains Calibration
Most breath alcohol machines need to be calibrated once a year, as well as after two failed calibration checks, or as the manufacturer's QA policy states. A calibration check is done regularly (once a month, or when someone has failed a breath test) to ensure that the machine continues to function up to par.
Breath alcohol machines are basically fuel cell breathalyzers and there are two different ways to calibrate these machines.
The first method is the “Dry Gas” method, in which a mixture of alcohol and inert nitrogen is administered through the machine manually and the machine is reset to match the gas concentration. The dry gas method is the more popular calibration method because it is simple and convenient.
The second method used to calibrate a breath alcohol machine is the “Wet Bath” method. The wet bath method is less popular as it is not portable and uses a mixture of water and alcohol in a specialized piece of equipment. It is also more expensive and is normally only used by the manufacturer and by some law enforcement.