The sampling system for the NHTSA-approved Intoximeters Alcomonitor CC used in DOT testing is designed to take an automatic sample once several parameters have been met.  The instrument monitors the breath sample as it is being provided.

• A flow rate of at least .2 liters of breath per second must be detected.  A “+” is displayed on the instrument to indicate that this condition has been met.  Once the “+” has been displayed, the instrument begins to measure the total breath volume of the provided sample.
• A minimum sample volume of 1200 cc is required for an automatic sample to occur.  The instrument indicates the minimum volume requirement has been met by displaying “++”.  A steady flow of breath is required for the period between the indication of minimum flow (+) and the indication of minimum volume requirement (++).
• Once the minimum volume requirement has been met and the subject’s breath flow begins to taper off, a breath sample will be captured for analysis.

In the event that these requirements are not met, the instrument aborts the attempted sample and allows one more attempt from the subject before aborting the test sequence.