GB/T 17650.2-2021 specifies the measurement method of acidity (pH measurement) and conductivity of cable or optical cable materials for combustion. The gas generated by the combustion of the material is collected and dissolved in water, the pH value of the solution is measured with acidity to determine acidity, and the conductivity of the solution is measured with a Conductivity Meter. The standard makes strict specifications for sample preparation, combustion experimental device, instrument operation process, data processing, etc., to ensure accurate and reliable results. This standard provides a quantitative basis for evaluating the impact of cable or optical cable combustion on the environment, and helps to ensure the mass of the product in terms of fire safety and environmental protection.