1. The flame-retardant characteristics of PVC pipes, the flame-retardant performance and oxygen index of PVC pipes are specified: PVC pipe manufacturers introduce the so-called ignition point, which generally means that when chemicals reach a certain temperature, they will naturally ignite and burn, but PVC pipes will not Spontaneous combustion, does not support combustion, and can self-extinguish, so there is no problem of ignition point. PVC pipe is a kind of flame-retardant material, it will burn when it comes into contact with the flame, but the flame will be extinguished immediately when it moves to the side.

2. The oxygen index of PVC is 48. The oxygen index refers to the minimum oxygen concentration required for flaming combustion of a material in a mixture of oxygen and nitrogen under specified conditions. It is expressed as the value of the volume percentage of oxygen. A high oxygen index indicates that the material is not easy to burn, and a low oxygen index indicates that the material is easy to burn. Under the specified test conditions, the minimum oxygen concentration when the material just maintains the flame combustion in the O2 and N2 mixed gas at room temperature is expressed as a percentage of the volume. The higher the oxygen index, the better the flame retardant performance.

3. PVC pipe connection method: if the pipe is damaged in a large area, the entire pipe needs to be replaced, the double socket connector can be used to replace the pipe; the solvent method can be used to deal with the leakage of the solvent bonding; at this time, discharge first Dry the water in the pipe and create a negative pressure in the pipe, and then inject the adhesive on the pores of the leakage part. Because the pipe is under negative pressure, the adhesive will be sucked into the pores to achieve the purpose of stopping leakage.

The patch bonding method is mainly aimed at the leakage of small holes and joints in pipes. At this time, choose the same diameter pipe with a length of 15～500px and cut it longitudinally. According to the method of bonding joints, the inner surface of the casing and the outer surface of the pipe to be patched are roughened, and then the glue is applied to the leaking area. The glass fiber method uses epoxy resin and curing agent to prepare a resin solution. After impregnating the resin solution with glass fiber cloth, it is evenly wound on the surface of the leaking part of the pipe or joint, and becomes glass fiber reinforced plastic after curing.