Wire and cable zr

ZR means flame retardancy. The flame retardancy is divided into three levels: A, B and C. ZB represents Class B flame retardancy, and ZR defaults to Class C flame retardancy.

Meaning of flame-retardant wires and cables

Under the specified test conditions, the sample is burned. After the fire source is removed, the flame spread on the sample is only within the limited range and extinguishes itself, that is, it has the ability to prevent or delay the occurrence or spread of flame. The combustion of cables is caused by external heating and produces flammable gases. To achieve the purpose of flame retardance, the three factors that cause combustion must be suppressed, namely, flammable gases, heat and oxygen. Therefore, the general method used for flame-retardant wires and cables is to add halides and metal oxides containing halogens into the sheath material, which is an excellent method to evaluate from the perspective of flame retardancy. However, because these materials contain halogens and release a large amount of smoke and hydrogen halide gas during combustion, the visibility in case of fire is low, which greatly hinders the safe evacuation and fire fighting of personnel, People are more suffocated by toxic gases. At present, with the continuous improvement of the level of science and technology, the problem of flame retardance has developed from halogen flame retardance in the past to low halogen and halogen-free flame retardance.

Differences of wire and cable models ZA, ZB and ZC

Flame retardant characteristics ZA>ZB>ZC, flame retardant cable A B C is classified according to the provisions of GB/T18380-2008 standard, and is used to evaluate the ability of vertically installed bunched wires and cables or optical cables to suppress the vertical spread of flame under specified conditions. Flame retardant type A refers to that the cable is installed on the test steel ladder so that the total volume of non-metallic materials in the test is 7L/m, and the fire supply time is 40 minutes. After the cable combustion stops, dry the sample, The maximum carbonization range of the measured sample shall not be higher than 2.5m from the bottom of the blowtorch. Flame retardant class B refers to that the cable is installed on the test steel ladder to make the non-metallic material in the test in the total volume 3.5L/m, and the fire supply time is 40 minutes. After the cable combustion stops, dry the sample. The maximum carbonization range of the measured sample shall not be higher than 2.5m from the bottom of the blowtorch. Flame retardant class C refers to that the cable is installed on the test steel ladder to make the non-metallic material in the test in the total volume 1.5L/m, The fire supply time is 20 minutes. After the cable combustion stops, dry the sample. The measured maximum carbonization range of the sample shall not be higher than 2.5m at the bottom of the blowtorch.