Difference between flame-retardant cable and fire-proof cable and precautions for fire prevention of cable (ZR is flame-retardant)
June 08, 2022
First, the difference between flame-retardant cables and fire-resistant fire-resistant cables
For flame-retardant cables, we require the IEC-332-1-2-3 standard at minimum, and the corresponding specification for fire-resistant and fire-resistant cables is IEC-331. The contents of the two assessments are different. Refer to Tian Chuanguo, “The Basic Knowledge of Wire and Cable”. Fire-retardant cables were produced in Shanghai Cable Research Institute and Wuxi Special Cable Factory in the 1980s, and were used in CCTV color TV center, CCTV Tower, Shandong TV Station, and Tianjin TV Station. The main differences between fire-resistant fire-resistant cables and flame-retardant fire-resistant cables are as follows:
(1) The fire-resistant fire-resistant cables and fire-retardant fire-proof cables have different technical structures and different functions.
(2) Flame-retardant fire-retardant cables shall have flame-retardant functions in addition to their own use in practice, but they shall have flame-retardant functions, and fire-retardant and fire-resistant cables may not necessarily have fire-resistant functions.
(3) Therefore, the use of fire-retardant and fire-retardant products is not an alternative to fire-resistant and fire-resistant cables.
When looking at advertisements and product sample data, we should carefully study and analyze them carefully. Don't be fooled by advertisements or exaggerated propaganda. For example, some manufacturers advertise that cables have a long life span and are overloaded, which is 100 times the normal current carrying capacity. Do you dare to use it? It is hoped that these manufacturers will develop their own proprietary technologies and produce true fire-resistant fire-resistant cables, which will be sent to the National Fireproof Building Materials Quality Supervision and Inspection Center for formal inspection and testing according to standards.
Second, think about fire accidents
Ruthless fire, hidden dangers in the open flame, prevention is better than disaster relief, responsibility is more important than Taishan, this is our designer must always keep in mind when designing, the author's former old colleague, in the design of the Tianyiyuan shopping center is because there is no detail Research, failure to comply with fire regulations, caused a fire, and was listed in the top ten list of fires in 1994. He was finally subject to probation, and he really regretted it. He was always in tears.
It can be seen that the design of building electrical is very important to the safety of the building. The following example focuses on the use of TN-S system and IT system coexistence design problems.
Example 1: In the electrical design of Peking University International Hospital, the concept of the designer system is unclear and inexperienced. The TN-S and IT systems are compatible and coexist. The chaos is out of the picture. The external auditor has not designed the pretrial examiner, and there is no medical treatment during the examination. The related content of the building is a serious dereliction of duty.
Medical building requirements for electrical are quite high. On the 232th page of the "2007 New Development of Building Electrical Technology" book, two experts Chen Liang and Yang Yue of the School of Electrical Engineering of Chongqing University wrote a standard for power isolation: the normal leakage of the heart operating table must not exceed 10 μA, and an insulation occurs. Its leakage current must not exceed 50μA in case of failure, otherwise it may lead to patient's "micro-shock" death. To this end, a 1:1 isolation transformer must be installed to supply IT system. See "Electrical Design Technology", 2008 Beijing Olympic Engineering For second-class buildings such as emergency rooms for hospitals, nursing care, and treatment rooms, see the article and attached figure 13. We must use real flame-retardant, fire-resistant and fire-resistant cables, and consider halogen-free and low-toxic anti-rat functions. Explain that Peking University International Hospital must use qualified fire-resistant fire-resistant cables.
Example 2: When constructing the CCTV, the color TV center and the CCTV Tower, we plan to use NH type fire-resistant fire-proof cables to meet the fire-fighting elevators, fire-fighting facilities of the tower and other fire-fighting facilities, but some leaders at that time thought that Burning cable, almost caused personal injury accidents. In short, we must study meticulously in the implementation of the fire code, and we must not covet it for a while. There are many current design tasks and the duration is short. Don't be greedy for easy moments, let the factory salesman design for you, so you will be very passive.
Third, the characteristics of flame-retardant fire-resistant fireproof cable
At present, the German fire protection cable production plant has been able to produce pre-branched fire-retardant fire-resistant fire-resistant cables, regardless of the number of branches, the length of how much, do not need intermediate connectors and cable terminations. One-time delivery facilitates work on the construction site and meets our requirements:
(1) The product has passed the national wire and cable quality supervision and inspection center and passed the test; passed the international standard of the British Standards Association (BS-6387c.wz), all tests pass, and the fire resistance standards are evaluated as follows:
I. 950 °C flame power 180min without breakdown;
II. Spraying with water at 650°C for 15 minutes without breakdown;
III. Under 650°C flame, it withstands 15 minutes of knocking vibration without breakdown.
