H2S gas detectors are used by a wide variety of industrial companies for safety reasons, e.g: Oil&Gas, Chemistry, Water Treatment. The detectors are usually installée! where H2S can be found in ambient air in order to prevent toxic risk. The tests, requested by the French Ministry for Environment, were conducted by INERIS in partnership with Exera (an association of companies and organizations which invest in instruments, measurement, control and automation Systems). This évaluation was carried out to investigate if H2S gas detectors can operate efficiently under différent operating conditions on industrial sites (température, humidity, pressure, interfering species, etc.). The measurement range of the detectors that were evaluated is 0- 20 ppm.