What’s The Difference?
For air crew, maritime and railway workers
With a Semi Conductor Breathalyzer, while the sensor is generally quite accurate around the two calibration points of 0.03% BAC and 0.10% BAC (UK limit 0.08%) the results can be less satisfactory outside of these ranges, and particularly so at lower levels below 0.03%. Needless to say, manufacturers all quote their accuracy as a figure +/- (x)% at the 0.10% level, and while this is generally repeated at this level accuracy does diminish at other measuring points.
A Fuel Cell, on the other hand, measures evenly throughout the range, hence why they are the only types of sensor used for Police grade detectors. Fortunately, while a Police standard detector (such as the Dräeger 6510) costs around £700 there are now several Fuel-Cell based Breathalyzers available at considerably less – the AlcoDigital LifeGuard for instance is just £199.
The other reason for the price difference is generally down to the sampling method. To get an accurate reading you need an accurate and consistent sample, but whereas the Fuel-Cell type of Breathalyzers also measure exactly 1.7ltrs of air each time (and expel the remainder through an air valve) the semi conductor models use either time alone (say a 3 second blow) or combination of time and pressure.
Because the levels tested within these industries are so low (just a quarter of the UK Drink-Drive limit) and the consequences so severe (in many cases the loss of an entire career, not just a job with a particular company) it is vital that an accurate and reliable device is used. In principle, while expensive, we would have to recommend the Dräeger 6510 as THE best device for the job, as it is exactly the same as the detector that would be used should you be unfortunate enough to find yourself in that situation. They are not cheap, but the ARE the best, TOTALLY reliable and by far the most accurate devices available. Considering what is often at stake, it may well be worth the cost, however there are now at least two other fuel-cell base devices available at much lower cost which may suffice.