Wire and cableTest method for smoke density and halogen content detection:

IEC 61034-1/ASTM E662 Emission of Smoke. This is the specification for smoke density in IEC and ASTM standards. The experiment consists of a 3m3 cube and a photometric measurement system with a light source, with alcohol inside a rectangular slot as the combustion source. A blower with a power of 10-15 m3/min ensures that smoke is evenly distributed on a windshield to prevent flame vortices from forming on the grooves. When alcohol burns, a recorder connected to the optical power source records the amount of light attenuation. Smoke density is measured by light transmittance. If it can achieve a light transmission value of 60%, the cable material will meet the low smoke standard. The higher the light transmittance, the less smoke the material releases during combustion.

ISO4589-2/BS2863 Oxygen Index LOI

This is the specification for oxygen index in ISO and BS standards. It refers to the situation where at room temperature, when the oxygen content of the air in the cable supply exceeds this oxygen index, the material will immediately burn. The higher the oxygen index value, the more flame retardant the material is. If the oxygen index of a material is 21%, it means that the material will automatically burn at normal room temperature. At normal room temperature, the oxygen content of air is 21%. Generally, the oxygen index of flame-retardant cables is greater than 33%. IEC60754-2 Gas Acidity Measurement (Corrosion) is used to measure the acidity of halogen acid gas produced by the material during combustion. It is determined by the pH value and conductivity of the aqueous solution. According to the experimental regulations, preheat the combustion furnace to 800 ℃, push a quartz tube with a built-in sample into the furnace, and start timing at the same time. Measure the pH value and electrical conductivity every 1 minute during the first 5 minutes of sample combustion, and every 5 minutes for the next 25 minutes. The pH value of general halogen-free cable materials will be greater than 4.3, and the conductivity will be less than 10 μ s; The lower the pH value, the higher the acidity of the halogen acid gas in the material. It is worth noting that when the HCL content is greater than 2mg/g but less than 5mg/g (i.e. meets the requirements of IEC60754-1), the pH value of its aqueous solution is also less than 4.3, which does not meet the requirements of IEC60754-2.

IEC60754-1/BS6425-1 Determination of Halogen Gas Content (Emission of Halogens)

This is the specification for hydrogen chloride (HCL) release concentration in IEC and BS standards. Halogens contain fluorine (Florine), chlorine (Chlorine), bromine (Bromine), iodine (Iodine), and the radioactive volatile element astatine (Astatine), which have high toxicity. According to the experimental regulations, when the combustion furnace is preheated to 800 ℃, a 1.0g sample is inserted into the furnace, and the HCL is dissolved in water using the airflow discharge rate. Then, the halogen acid content of the aqueous solution is measured. If the release of halogen acid during cable material combustion is less than 5mg/g, it can be called halogen-free cable (LSOH). If the release of halogen acid (HCL) is greater than 5mg/g but less than 15mg/g, it can be called low halogen cable (LSF). It is worth noting that the IEC60754-1 method cannot be used to determine materials with HCL content less than 5 mg/g, that is, it cannot determine whether they are "halogen-free". The IEC60754-2 method can be used to determine whether it is completely halogen-free.