JJF 1523-2015 "Outline for Type Evaluation of Carbon Monoxide and Carbon Dioxide Infrared Gas Analyzers" is applicable to the type evaluation of carbon monoxide and carbon dioxide infrared gas analyzers. The standard describes in detail the composition, structure and working principle of the instrument, which is mainly composed of infrared Sensors, electronic components and display parts. Infrared Sensors convert the detected gas concentration into an electrical signal, and display the concentration value after processing by electronic components. The instrument is divided into discontinuous and continuous measurement types according to the working state, and is divided into diffusion and suction types according to the Sampling method. The standard cites relevant infrared gas analyzer standards and environmental test methods to ensure accuracy and Reliability in the evaluation process. The outline is suitable for the needs of industry and environment monitoring for precise analysis and calibrating of carbon monoxide and carbon dioxide concentrations.