If you’re looking to purchase a breathalyzer for commercial, legal or personal purposes, there are several considerations you need to make. You'll very quickly run up against two different types of alcohol breathalysers: those that use a semiconductor sensor and those that use a fuel cell sensor. Yet even within each type, there are factors that can increase or decrease accuracy as well as ease of use.
Here we examine the differences to help you decide which kind of alcohol breathalyser you should buy for different purposes.
Buying a Breathalyzer: Essential Information
You should always buy breathalyzers that:
- Meet required Australian Standards. This is especially vital for workplace and law enforcement use.
- Can be recalibrated. Over time all alcohol breathalyzer sensors become less accurate and must be recalibrated.
- Are calibrated by trained professionals. Some brands require you to replace your own pre-calibrated sensor. Will this stand up in court? Leave it to the trained specialists
- Has a high accuracy in a controlled environment. The controlled accuracy reading should be +/-0.01% variance.
- Has a good accuracy, +/- 10%, as per AS3547
However, you don't need to search for alcohol breathalyzers that claim 100% accuracy. Variations in body types mean that +/- 0% accuracy is impossible to achieve - any breathalyzer that claims this is making a false statement.
How do they work?
Semiconductor breathalyzers carry out an internal reaction of ethyl alcohol exhaled by the test subject into acetic acid and water, which can generate an electric current. The amount of current generated is assumed to be proportional to the amount of alcohol in a person's blood.
However, the prevalence of other substances that mimic acetic acid, as well as the vulnerability of the sensor itself to loss of accuracy, means the semiconductor breathalyzers rarely have a satisfactory accuracy score. Their long term accuracy is far poorer than fuel cell sensors.
Who should buy breathalyzers using semiconductors?
If you are simply screening for the presence of alcohol on somebody's breath (for example, in a workplace) and will be doing further testing to confirm levels, buying a breathalyzer that uses semiconductors may be appropriate, however not recommended.
Readings from semiconductor alcohol breathalyzers are not generally admissible as evidence in court.
Fuel Cell Breathalyzers
How do they work?
Fuel cell breathalyzers have two platinum electrodes inside the sensor, with an electrolyte material between them. As the ethyl alcohol passes through them, the platinum oxidizes it into acetic acid, protons and electrons; the electrons generate a current and that current is measured.
Who should buy breathalyzers using fuel cell sensors?
Fuel cell sensor alcohol breathalyzers are utilised at random breath test stations as well as by the largest employers in the country. If you need an accurate reading, you should buy a breathalyzer using fuel cell technology.
How Do I Know Which Type of Breathalyzer I'm Purchasing?
You'll always need to check the product's technical information to see whether it utilises semiconductor or fuel cell technology to obtain a reading.
If you're thinking of buying a breathalyzer that doesn't come with technical information, look to the price tag as a clue to the type of technology it uses. Semiconductor models start at around $40 and range up to several hundred dollars. Quality fuel cell alcohol breathalyzers start at a couple of hundred dollars and range up to a couple of thousand dollars for law enforcement models.
Passive versus Active Breathalyzer Buying Guide
Passive alcohol breathalyzers only need to be spoken into to obtain a BAC reading (positive/negative only), whereas active alcohol breathalyzers must be blown into.
Active units are slightly less prone to environmental contamination, and the reading cannot be affected by the distance at which the unit is spoken into. If accuracy is a concern (for example, in personal breathalysers), buy a breathalyzer that needs to be blown into.
At Breathalyser Sales and Service, we stock only higher quality fuel cell breathalyzers to buy for personal or workplace use. If you have any questions about particular models, don't hesitate to contact us!