Workplace atmospheres. Electrical apparatus used for the direct detection and direct concentration measurement of toxic gases and vapours. Guide for selection, installation, use and maintenance|Gas detectors, Electrical equipment, Gas analyzers, Toxic gases, Gases, Vapours, Dangerous materials, Environment (working), Chemical analysis and testing, Industrial air pollutants, Occupational safety, Selection, Installation, Maintenance, Testing conditions, Sampling methods, Gas analysis, Measurement characteristics, Accuracy, Calibration, Inspection, Performance, Instructions for use, Heat measurement, Semiconductor devices, Electrochemical devices, Electro-analytical methods, Infrared radiation, Spectrophotometry, Photometry (chemical analysis), Flame photometry, Emission spectrophotometry, Thermal conductivity, Colorimetry, Mass spectrometry, Electrical conductivity, Luminescence, Potentiometric methods, Gas chromatography, Transportation, Storage, Electrical safety, Training, Personnel