Breathalyser Readings Explained
Breathalyser Readings Terminology
- BAC= Blood alcohol concentration
- Commonly displayed as a percentage %BAC or mg/100ml.
- Few breathalyzers on sale in UK display in BAC
- BRAC= Breath alcohol concentration.
- Most newer models of breathalyzer display BRAC in mg/L (milligram per Litre)
- Accuracy= the selectivity achievable when the breathalyser sensor is correctly calibrated.
- This is often displayed as the variation accepted in %BAC ie +/- 0.01%BAC means the breathalyzer will display with an accuracy of + or - 0.01 on the display 0.05 the breathalyser may display a variance of 0.04 to 0.06 on a series of 3 tests done in succession.
- A greater variance would indicate a possible loss of calibration, sensor failure, evaporating mouth alcohol or poor breath sampling technique.
- Calibration = the service which sets the reading accuracy of the sensor.
- Breathalysers which do not have interchangeable sensor modules will need to be sent for service periodically for a calibration service to maintain their accuracy.
- A chemical breathalyser is a single-use disposable breathalyser kit which you blow through.
- A chemical reaction takes place between the alcohol in your breath and the crystals in the breathalyser and produces a colour change.
- The colour corresponds to a particular level of alcohol in the blood. They come with a chart so that you can interpret the results.
- They are highly accurate around 98%, and are a very good first line alcohol screening tool.
- They have an expiry date after which they should be discarded.
- Browse our range of single use chemical alcohol breathalysers
- A digital breathalyser is an electronic breathalyser rather than a chemical breathalyser.
- It contains a sensor that detects alcohol in the breath sample.
- The accuracy of the breathalyser tends to follow price with the more expensive models having higher accuracy levels.
- All the models that we stock are highly accurate provided that they are used and stored correctly, and re-calibrated correctly.
- See our current digital breathalysers that we have for sale
Re-calibration of digital breathalysers
- A digital breathalyser will need regular re-calibration to make sure that it is retaining its accuracy.
- For the models with a semiconductor sensor, this usually means simply purchasing a new breathalyser sensor about every 6 months, and fitting it yourself.
- Some of the newer fuel cell sensor models also have a sensor which you can change easily yourself.
- Models such as the Draeger 6820 breathalyser will require returning to a calibration centre.