Accuracy Check Methods

Breath alcohol testing instruments are calibrated and checked for accuracy utilizing an ethanol standard with a known alcohol concentration.  There are two types of standards that are widely accepted and commonly used: 
  1. Wet Bath Standards
  2. Dry Gas Standards

The value of the Standard used is usually determined by  Quality Assurance Plan (QAP).  For example, law enforcement agencies that arrest drunk drivers based on a legal limit of  0.080 BrAC will typically check their evidential breath alcohol testing devices with a standard that has a target value at or near 0.080 BrAC.  Many law enforcement agencies also use 0.100 standards.   The NHTSA (National Highway Traffic Safety Administration) approved Intoximeters QAP required to be used in conjunction with US DOT Workplace testing (49 CFR Part 40.233) designates standards with a stated equivalent value between 0.020 and 0.040.

Fuel Cell sensors are linear output devices and can thus be calibrated for the dynamic range of readings at any point within that range.  Similarly, these devices can also be checked at any point to determine that they are in calibration throughout the entire range of readings. As a result, an instrument calibrated at one level will also be calibrated for other applications that have a need to check samples for yet another level. 

Technical Services home page