Dräger Alcotest

What it is

Alcotest is the name of Dräger's breath alcohol testing products. The Lübeck company introduced its first Alcotest tube in 1953. Since then the range has evolved into handheld electronic breathalysers for police roadside checks, evidential instruments for police stations and alcohol interlocks that prevent a vehicle from starting if the driver has been drinking.

How it works

The original Alcotest tube contained sulphuric acid and yellow potassium dichromate. When a person blew through it, alcohol in the breath reacted with the chemicals and turned them green; the length of the colour change indicated the alcohol concentration. Modern devices use electrochemical fuel cell sensors, in which alcohol is oxidised and generates an electric current proportional to its concentration, or infrared sensors, which measure how ethanol molecules absorb infrared light. Dräger's 1998 Alcotest 7110 Evidential MK III combined both methods.

Why it stands out

Breath testing made it possible to enforce drink-driving laws quickly and objectively at the roadside, without the need for an immediate blood sample. According to Dräger, the Alcotest 7110 Evidential MK III was the first breath alcohol device whose results could be admitted as evidence in court. The company is known more broadly for medical and safety technology such as ventilators and gas detectors.

Where you meet it

Police officers in many countries carry Dräger handheld breathalysers, and evidential devices are installed in police stations. Alcohol interlocks are used in commercial fleets and in programmes for convicted drink drivers. Workplaces in safety-critical industries also use them for testing.