Think of calibration as a service on your car; if you use the car a lot, you need to have it serviced more often – but even if your car just sits in the garage for most of the time, it still needs an annual service. Sometimes, leaving your car out of use can lead to more service work than using it regularly. It’s the same with a breathalyser. Most people will do less than 500 tests a year, in which case an annual service will be fine. However if the breathalyser spends long periods of time out of use, this in itself can lead to problems with the sensor drying out. It’s best to use it at least a couple of times a month to make sure this doesn’t happen.
Another reason for regular calibration is because if a breathalyzer hasn’t been recalibrated for some time it is possible that the sensor will move so far out of range that it cannot be brought back into the operating range. We therefore recommend personal devices be calibrated every 12 months, or if you’re using it to test someone else every 6 months. Using a breathalyser within less than the minimum time after drinking (20 mins) or smoking (10 mins) can dramatically reduce a sensor’s life before it needs recalibrating. In some cases the whole device will need replacing if excessive smoke/alcohol or other contaminants have been blown into the unit. Users must remember that these are sensitive medical instruments and must be used in accordance with the supplied user manual.