Alco-Sensor FST Calibration

Prior to calibrating an Intoximeters breath alcohol testing instrument, you should be trained to perform the calibration functions as allowed under your specific testing program. The calibration procedures below are designed to help you ensure precise and accurate test results.  If, according to your program, you are not authorized to perform calibrations, please see your program administrator or contact Intoximeters for assistance.  Typically, a calibration is not required if the results of accuracy checks are within the programs acceptable tolerance.

The procedure for calibrating an Intoximeters breath alcohol testing device will vary based on instrument model and type.  Refer to the Operator's Manual of your instrument for specific instructions on calibrating your device. DO NOT perform this procedure unless you are authorized to do so.

Getting Started
Below are basic calibration instructions for the Intoximeters Alco-Sensor FST breath testing instrument.  Unless your testing procedure dictates otherwise, a calibration is only necessary if an accuracy check has proven the instrument to be out of tolerance. Some users choose to calibrate the instrument more frequently to ensure that the instrument remains within tighter tolerances than required by their quality assurance plan and this process will not damage the instrument.

To calibrate an Alco-Sensor FST, the unit temperature must be between 15ºC - 35ºC.  If the temperature is not within this range, the unit will display E09 or E10 and block the calibration procedure. (Note: An ASFST standard software requires a calibration alcohol standard concentration between .015 - .200).

Tools Required: Before beginning have items available: instrument, calibration standard, new mouthpiece, calibration logbook


  • Dry Gas Standard & Regulator*
    *(6 liter per minute (lpm) flow rate for automated or manual sampling)
    *(1.5 liter per minute (lpm) flow rate for manual sampling)
    See the difference between the two.
  • True-Cal Device
  • Alco-Sensor FST
  • New Mouthpiece


Note: A calibration standard can be a: 
  • Dry Gas Cylinder and Regulator
  • Wet Bath Simulator and Solution

For this demonstration, a dry gas cylinder is used as the standard - value (at sea level) of.082%. A True-Cal device was used to give the true value of the standard at the time of our demonstration – the True-Cal will adjust the expected gas value for the current atmospheric pressure. Therefore, the target value for this demonstration is .080

True-Cal displays .080

Pre Operation Checklist
  • Know the expected value of the standard you will be using to calibrate your device. (For this demonstration the value of the dry gas standard used was .080% - see picture above.)
  • Check the temperature of the Alco-Sensor FST - it must be within a specific range (15ºC - 35ºC) in order to perform the calibration.
  • Purge the dry gas regulator for several seconds.