Breathalysers come in 2 basic sensor formats. Semiconductor (common in most models) and fuel cell (rare and expensive until recently)
Fuel cell breathalysers do in theory offer greater accuracy and selectivity for alcohol, but do not yet offer onsite sensor exchange, so unlike modern semi conductor breathalysers, you still have to send the complete breathalyser to a service centre, to be calibrated and serviced at regular intervals.
A fuel cell breathalyser will in the main keep its calibrated accuracy for longer than a semi conductor sensor, but no absolutes are given by manufacturers, so it is hard to be certain how often this will be. As a rough guide most semiconductor sensors will give between 300 and 700 tests. Fuel cells will normally be operated in critcal environments where calibration service is recommended at 3 monthly intervals (maximum 6 months for light users) so I guess it comes down to how many tests you are expecting to conduct.
Will a fuel cell breathalyser be considered accurate enough for evidential use ? > No.
Will a “home office approved” fuel cell be accurate for evidential use ? > No.
Will a breathalyser with a print-out be suitable for evidential use ? > No.
Explanation, simple unless the kit you buy and purchase has been calibrated under a home office approved scheme on the day of testing, the accuracy will in all cases be questioned and it is the onus of the testing agent to prove accuracy if presenting evidence, either to a court or tribunal.
So all these units should be operated as screening tools, to identify and quantify a suspected problem. In this role they can be invaluable, but where a problem is identified, a voluntary “real blood” alcohol assay, conducted in an accredited laboratory remains the gold standard evidential test
So would we recommend spending £400-600 on expensive home office approved fuel cell breathalysers for testers other than Police authorities ? > No. By all means consider fuel cell units, particularly if you aim to operate zero tolerance testing and need high accuracy and selectivity at the low levels of alcohol you’re looking to detect, but spend £100-150 tops (DA8000 fuel cell breathalyser) and for most of you, the top end semi conductor units like the AL7000 may be better.