Definition - What does Air Blank mean?
An air blank, with regard to alcohol testing procedures, is the testing of an ambient air sample that contains no alcohol by an evidentiary breath testing device. If the EBT uses gas chromatography technology, the air blank reads the EBT's internal standard. The air blank is used to demonstrate that the device is functioning properly before the subject is asked to provide a breath sample.
WorkplaceTesting explains Air Blank
An air blank is required before a confirmation test may be performed. If the breath alcohol technician fails to perform an air blank on an evidential breath test device (EBT) prior to performing the confirmation test, the test will be considered invalid. A test of ambient air in most devices, or the internal standard test for gas chromography devices, should yield a result of zero if the device is functioning properly. If the air blank reading shows a positive result for the presence of alcohol, then a second air blank test must be conducted. Only if a reading of 0.00 is presented in the first testing or the subsequent retest may a breath test of the subject employee proceed. This type of testing is to calibrate the machine and ensure no false positives are returned.