In recent years, the process of urbanization has been accelerating, urban construction has advanced by leaps and bounds, and the structure and functions of buildings have become increasingly complex. Fire-fighting facilities and equipment within buildings have also become more comprehensive and larger. Such a series of developments put forward higher requirements for the design of fire protection electrical fire protection, and also put forward higher requirements for the distribution of fire protection electrical equipment distribution lines. Therefore, in the design and construction of the project, it is emphasized that the electrical distribution lines of the fire fighting equipment should meet the reliability requirements, ie, safety and fire resistance, so as to ensure that the fire protection equipment will not be interrupted during the fire and the duration of the power supply will be guaranteed.
In recent years, the process of urbanization has been accelerating, urban construction has advanced by leaps and bounds, and the structure and functions of buildings have become increasingly complex. Fire-fighting facilities and equipment within buildings have also become more comprehensive and larger. Such a series of developments put forward higher requirements for the design of fire protection electrical fire protection, and also put forward higher requirements for the distribution of fire protection electrical equipment distribution lines. Therefore, in the design and construction of the project, it is emphasized that the electrical distribution lines of the fire fighting equipment should meet the reliability requirements, ie, safety and fire resistance, so as to ensure that the fire protection equipment will not be interrupted during the fire and the duration of the power supply will be guaranteed.
Wire and Cable
In dark applications, the pipe should be worn and laid in the non-burning structure and the thickness of the protective layer should not be less than 30mm. Here the tube can be worn through metal tubes or flame-retardant plastic tubes. This laying method is a more practical method in engineering practice, which is safe, reliable, and economical. The requirements for the thickness of the protective layer not less than 30mm after laying the protective metal pipe after being protected in the non-burning body structure are mainly determined by referring to relevant test data. The test results show that according to the standard time-temperature curve for the fire test, the 30mm thick protective layer is within 15min, the temperature of the metal tube can reach 105°C; at 30min, it reaches 210°C; at 45min, it can reach 290°C. There are also relevant experimental data showing that when the metal reaches this temperature, the temperature of the distribution line is approximately 1/3 lower than the above temperature, and the supply of power can be guaranteed within this temperature increase range. In actual fires, it is also proved that this laying method can guarantee the continued supply of electricity to electrical equipment.
When fire-retardant or fire-resistant cables are used, fire protection measures may not be adopted for laying in cable wells and cable trenches. At present, there are many types of flame-retardant, fire-resistant and heat-resistant wire and cable on the market of electrical products. However, some of the wires and cables commonly used in the market can easily emit a large amount of toxic fumes when exposed to heat, some have poor impact resistance, and some have poor load running capability at high temperatures. What we need is to have both strong impact resistance and reliable load operation at high temperatures. Therefore, the design should use the appropriate distribution lines for different locations. At present, the country has corresponding industry standards for the testing of fire-resistant wire and cable and flame-retardant wire and cable, and specifies the technical requirements, test methods, and testing rules for related products.
However, it should be noted that the ability of flame-retardant wires and cables to resist failure is lower than that of fire-resistant cables. Therefore, the flame-retardant cables laid in cable wells and cable trenches should be separated from other types of cables to avoid the fire caused by other cables. Short circuit. When mineral insulated non-flammable cables are used, they can be applied directly. Mineral Insulated Cable (GB13033.1~3-91): It is a cable composed of copper, copper sheath and magnesium oxide insulation. It has many superior performances that are unmatched by other cables.
1. High temperature resistance: Considering the service life, the normal continuous operating temperature of mineral insulated cables is 250 degrees or less. This is because the speed of the copper jacket will be faster than 250 degrees. It does not mean that the mineral insulated cable is below 250 degrees. Can not be normal operation, in fact, mineral insulated cable is precisely with excellent high temperature performance, normal working temperature of 950 degrees for more than 3 hours, even at a short time near the temperature of 1083 degrees Celsius temperature of copper, and magnesium oxide insulation material in this way The temperature does not change in any nature.
2. Explosion-proof: The cable is composed of seamless copper jacket, tightly packed magnesium oxide insulation material and copper wire core, which can withstand huge external forces, and can prevent steam, gas and flame from entering the electrical equipment connected to the cable. , In the chemical and flammable and explosive environment can prevent the chain caused by a chain explosion.
Consumer wire and cable
3. Corrosion resistance: The copper material that constitutes the cable sheath is itself an inactive metal with high corrosion resistance. In most cases, no additional protection measures need to be taken, especially for the chemical environment and ground. Buried laying needs. In the case of laying under certain special circumstances (such as ammonia atmosphere) that have a corrosive effect on the copper sheath, an outer PVC sheath should be used.
4. Mineral insulated cables eliminate the potential for smoke and toxic gases from the source of the components. Particularly suitable for underground construction, underground transportation, tunnels, stations, airports, docks, theaters and other places where people gather.
5. Mechanical shock resistance; 6. Water resistance; 7. Large current carrying capacity; 8. Copper sheath can be used as ground wire; 9. Long service life; 10. Lower engineering cost.
The laying of distribution lines for fire-fighting electrical equipment is an important factor related to whether or not the fire-fighting electrical equipment can work normally under fire conditions. The laying of power distribution lines for fire-fighting electrical equipment should be well established and ensured within a certain period of time in case of fire. Being intact, we also need to continue research and practice in many aspects.
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