How are industrial gases classified for detection purposes?

Industrial gases are primarily categorized into three types: Combustible Gases (e.g., Methane, Hydrogen) which pose explosion risks; Toxic Gases (e.g., Carbon Monoxide, Hydrogen Sulfide) which threaten health even at low concentrations; and Asphyxiant Gases (e.g., Nitrogen, Carbon Dioxide) which displace oxygen and cause suffocation.