In recent years, with the rapid development of economic construction around the world, the city’s high standard and high requirements of the building such as spring, rising, the fire of these important buildings put forward new requirements. According to the fire department’s statistics, the past large-scale fires, relying on the building’s own fire protection system to quickly extinguish the fire, not very perfect, most of the fires with the help of external fire protection system to extinguish the fire, obviously, the small fires have become large fires or mega fires, the lesson is profound.
How to improve the building’s own fire protection system, the fire can be nipped in the bud in a timely manner, not to expand it, this is a systematic project is more complex.TST CABLE small only in the fire cable system to make some preliminary analysis to explore.
The development of fire-resistant cable is also very fast, more varieties, here TST CABLE can only analyze some of the commonly used varieties, commonly used fire-retardant cable V-type flame retardant, W-type flame retardant fire-resistant, YV-type flame retardant, YJV-type flame retardant, DWYJY or DWYJE-type flame retardant fire-resistant, as well as the metal sheathing of the inorganic (mineral) insulated type, obviously, differentiate between them, fire-retardant cables are only Two types, organic insulation type, inorganic insulation type.
Organic insulation type flame retardant cable:
- VV type (PVC/PVC), cable insulation and sheath are polyvinyl chloride, the type of cable materials contain flame retardant factor halogen “chlorine” has a good flame retardant, and abundant raw materials, create a mature process, cheap, but the cable has fatal flaws, because it contains gas ignition point of about 450 ℃ in the combustion of a large number of effect out of the HCE gas and other There is a trace of toxic gases, its toxicity index reaches 15.01. people in which the chance of escape is only about 2MM, at the same time will produce a large amount of smoke, smoke density Dm = 500-60 transmittance is only 10-20% (no visual field). HCE gas will also produce secondary pollution will be serious corrosion of electrical equipment and other equipment. Therefore, VV-type flame retardant fire-resistant cables are not used in some countries.
- YJV type (XLPE/PVC) cable insulation is cross-linked polyethylene, sheath or PVC. insulation to add aluminum hydroxide (all U.S.) as a flame retardant, this type of cable carrying capacity is greater than the VV-type material is sufficient, the process is mature and inexpensive, but also the toxicity index down to 7, the smoke density down to 300, transmittance up to 40-50% (visual field fuzzy), the person in which the chance of escape is about 10MM or so, PE ignition point of 340 ℃ (low) there is a mild secondary pollution, there is also a disadvantage in the crosslinking is not pay attention to, will produce in the insulation layer, “water tree”, not only shorten the life of the cable, but also cause short circuits.
- YJY or YJE type (XLPE/XLPE), we call it low-smoke halogen-free type, flame retardant aluminum chloride (magnesium), the material is still sufficient, and the creation of some of the difficulties of the process, the authentic YJY electricity, the price is more expensive than the first two. The biggest advantage of the cable is burning in the toxicity index is only 0.79 people escape time up to 20-30MM, smoke density of 100, light transmission rate is greater than 40-50% (clear vision), no secondary pollution. The type of cable with PE materials with a low ignition point (340 ℃), low oxygen index (18) high calorific value (combustion-induced energy), improper crosslinking will produce “water tree”.
The above three kinds of flame retardant, fire-resistant cable, all belong to the organic insulation type, is flammable, and its fire resistance is dependent on several layers of mica tape wrapped around the conductor. We all know that the coefficient of expansion of the mica tape is very large, it must rely on the outside of the fire-resistant protective layer, once the fire (according to the temperature and time curve) 5MM temperature can reach 560 ℃, the insulation of organic insulated cables is the sheath is burned all the way to the end, the mica tape immediately loosened, it can maintain the integrity of the line? These electrical intricacies in the fire on the fire system power supply possibilities.
Inorganic insulation type flame retardant cable
Metal sheathed inorganic (mineral) insulated cable, referred to as flexible fire-retardant cable. The cable mainly has ten major features.
I. Reasonable structure and advanced technology
- The conductor adopts multi-stranded stranded wire with uniform thickness, non-oxidized and smooth surface, good flexibility and long length.
- Insulation is made of inorganic (mineral) tape wrapped around the conductor, and the mineral tape is heat-resistant up to 1375℃, resistant to moisture, high temperature, corrosion, and not aging.
- The sheath is made of copper (1083C) sheath, continuous rolling pattern, with a large length heat dissipation surface, easy to bend.
Second, the electrical characteristics, fire-resistant properties, environmental characteristics are excellent
- Electrical characteristics compared with similar mineral insulated cables, small resistance index, large current-carrying capacity (equal cross-section), uniform insulation, not easy to crack.
- Fire resistance characteristics, a one-time fire test through the National Fire Testing Center (950 ℃, 90mm), successfully passed the British BS6387 standard (the highest external fire-resistant cable requirements): 950-1000 ℃, excellent, and then to 650 ℃, 15cmm spray test and 950 ℃, 15cmm impact test, can maintain the integrity of the line.
- Environmental protection characteristics, non-toxic and smoke-free combustion, does not produce harmful gases, light transmission rate of more than 60%, clear vision, no pollution, copper can be recycled and reuse, waste does not pollute the environment is a green product.
Third, large cross-section cable length
Large cross-section, single-core cable up to 630mm², multi-core cable up to 70mm². The overall cross-section can be produced according to user requirements. Long continuous length, single-core and multi-core limit length up to 2000 meters.
Four, good moisture resistance
Cable ends do not need to be sealed (no sealed terminal joints), in the general environment of the site can be any break cable and T-connect the branch, the same practice as ordinary organic insulated cables.
Five. Flexible
Production can be continuously coiled in the standard cable tray, installation can be smoothly released, not twisted, the biggest advantage is that the installation can automatically eliminate the destruction of natural forces and electrodynamic forces.
Six, good dynamic thermal stability
As the cable has a certain degree of flexibility, once the short circuit occurs, not like copper objects damaged by electromotive force, thermal stability is more reliable, for example: 15 of the short-circuit conductor temperature reaches 250 ℃, the current density of 143Am ㎡. Visible short-circuit current, such a large short-circuit current can be all the other appliances in the system is damaged, and 250 ℃ (for mineral insulated cable (950 ℃) temperature is absolutely not damaged. Therefore, the design does not have to calculate the thermal stability.
Seven, can do multi-core cable
YTTW to do with each other to block the finger uniform multi-core cable, and can produce 4x70m ㎡ multi-core cable, multi-core cable than a single-core cable has good electrical performance.
Eight, can trunking type power distribution eight.
Trunk-type power distribution can save a lot of copper wall material and save investment, and can use chain distribution, chain distribution by the strict limits of the code YTTW cable trunk-type power distribution, you can use T-connection, branch box branch and prefabricated branch cable branch, and branch point of the fire-resistant mounting level point cable body is the same.
Nine, easy to install
YTTW cable can be numbered, eliminating the need for bridges, electric installation does not require specialized technicians, special tools (especially the blowtorch), around the release line, break, do the terminal head with ordinary organic insulation electric a few sections of the same. When installing the cable, there is a natural serpentine”, so there is no need to install S-shaped or S2-shaped buffer joints at intervals of 30M, and it is not necessary to install a section of expansion joints when passing through the expansion joints of the building, as long as some cables can be left at the expansion joints. Cable termination head practice is the same as ordinary cable, no space size requirements for the equipment distribution box. When there is a corner in the installation space, the electricity can be bent with the garden lone. Cable can also be installed in high temperature (950 ℃) below and low temperature (-40 ℃) of the place, but also do not need high price installation accessories and maintenance-free.
Ten, the long-term use of fewer hidden problems, long life, the overall benefits are obvious
First of all, YTTW cable without intermediate joints, so the point is reduced, followed by the cable without high temperature resistance, but also has a certain degree of flexibility, not only to eliminate thermal expansion and contraction of the natural forces of destruction, while eliminating overload short-circuit generated by electrodynamic and thermal stress damage. Secondly, the cable’s good fire-resistant properties, you can maintain the integrity of the line in the fire, normal power transmission
In terms of economic indicators, it can be compared with low-smoke halogen-free flame retardant fire-resistant cable DWZANA-YJY.
- YTTW four-core cable instead of YJY five-core cable.
- YTTW cable can be selected as a lower cross-section gear than YJY cable under the same carrying capacity;
- Reliability of energized fire extinguishing in the fire, YITW cable is greater than YIY cable.
- Life YTTW flame retardant cable is greater than YJY flame retardant cable.
- For a specific project investment YTTW cable is greater than YJY cable, but the social benefits and comprehensive economic benefits, YTTW is greater than YIY, in short, organic insulated cables and YTTW insulated cables are not comparable.
TST CABLES–The global leading supplier of high temperature fire resistant and flame retardant cables.
TST CABLES specializes in providing high temperature fire retardant cable applications and solutions, we provide various specifications of fireproof cable manufacturing process for railroads, aviation, ships, nuclear power, oil and gas, wind power and other industries, cable material selection are required to undergo rigorous design and testing, to ensure that the cable in the normal operation and fire, high temperature and other extreme conditions of safety and stability. When choosing fire protection cables, the most suitable product should be selected according to the specific application scenarios and needs, taking into account the performance, safety, cost and other factors of the cable.
