What’s a Breath Alcohol Calibration Standard?
We talk to our customers about the importance of maintaining the accuracy of their breath alcohol test instruments by performing Accuracy Checks and Calibration Adjustments, and we devote a significant amount of our classroom BAT training on how to perform these procedures as well. An element that sometimes doesn’t get as much discussion is the one thing necessary to perform Accuracy Checks and Calibration Adjustments: the Calibration Standard.
A Calibration Standard is a known quantity that we use to compare against our measuring device – in this case, a breath alcohol testing device. In medical settings calibration standards are frequently called “controls, and the process that we typically call Accuracy Check is called “running a control.” Depending on the particular device, it is not unusual for staff in medical settings to run a “high control” and a “low control” in order to verify that the device in question is giving correct readings. In alcohol testing, however, it is customary to verify at only one point.
There are only two basic types of breath alcohol Calibration Standards: Compressed Ethanol Gas and Wet Bath Simulator. Each type produces an ethanol vapor with a precisely known alcohol concentration – for example, .100 BrAC. Most programs use one or the other; it is rare for an alcohol testing program to incorporate the use of ethanol gas and wet bath simulators.
Ethanol gas calibration standards have several different names: dry gas, gas tanks, and gas canister are just a few. Most workplace alcohol testing programs use evidential quality ethanol gas standards. Most of these gas tanks hold enough gas for hundreds of accuracy checks and have a shelf life of up to two years.
AlcoPro also offers a non-evidential gas standard called the Mini Alcohol Can. Mini Alcohol Cans are a less costly alternative for checking that an Alco-Sensor is responding appropriately to alcohol, and are appropriate for use in non-evidential testing programs such as substance abuse treatment programs. Mini Alcohol cans hold enough gas to perform 10 accuracy checks.
In the alcohol testing business the Wet Bath Simulator is usually simply called a “simulator.” Simulators are widely used by law enforcement agencies, although more agencies have been moving to using ethanol gas in their maintenance programs. Simulators require AC power, require warm up time, and they require pre-mixed simulator solution that can be used only for a certain number of tests before it must be replaced.
Did you know…?
Despite the extra effort involved in using simulators, they replicate the breath of an intoxicated person very well. In fact, simulators were first invented to do just that – replicate the breath of an intoxicated person – as a way to train the first operators of breath alcohol testing devices. It was several years later that simulators were refined to the point that they could be used as calibration standards.
Did you also know…?
In addition to publishing a Conforming Products List for Evidential Breath Test Devices and for Alcohol Screening Devices, NHTSA publishes a Conforming Products List for Calibrating Units for Breath Alcohol Devices. The Quality Assurance Plan for most evidential breath test devices recommends or requires that the user use a calibration standard that is on this conforming products list.