measures used in cable fire protection
from：guichao author：admin click： 394 addtime：2016-08-30 17:16:05
at present, the cable fire prevention measures are as follows:
(1) fire resistant cable and flame retardant cable
fire resistant cable is a cable that can keep the power within the specified time (about 4 h) under the condition of fire. in case of fire in case of the passage of the lighting, emergency radio, fire alarm devices, automatic fire facilities and other emergency equipment, the normal use of personnel in a timely manner to evacuate. during the fire, it also has the characteristics of small amount of smoke, low smoke toxicity. this type of cable is more expensive, the general application of higher requirements for fire safety conditions in high-rise building, electric power, petroleum, chemical, shipbuilding and other occasions, the cable is necessary for emergency power supply, fire pump, elevator, signal communication system. this type of cable in shanghai cable factory and other manufacturers have come out, and has mass production, but at present these cable factory production of refractory cable voltage level is only 1 kv and below.
flame retardant cable is the main feature of non ignition (or after the ignition is limited to a certain range of fire), so this kind of cable is suitable for high flame retardant requirements, fire prevention, explosion prevention. now developed a flame retardant chlorosulfonated polyethylene rubber sheathed cable (the voltage rating of 6 kv), flame retardant xlpe and flame retardant cable for ship, and low smoke halogen-free cable series, these cables have been used in many engineering.
at present, china's production of refractory and flame retardant cable specifications, structural insulation performance and test methods, are in line with international and iec3328 standards. in the production practice, flame retardant cable is widely used, the cable fire accident is obviously reduced, which ensures the safe operation of power plant and power grid, and has obvious economic benefits and social benefits.
(2) fire retardant coatings
in recent years, china has developed a variety of fire retardant coatings, by the national identification of qualified products used in practice and proved effective. the acrylic paint is suitable for the bad environment, and the modified amino coating is suitable for the wet environment.
in addition, the expansion of vinyl chloride fire retardant coatings, in 1988 by the ministry of public security organization of the new product identification. the coating is characterized by the expansion of the fire in case of a uniform and compact thermal insulation layer, a good heat insulation, water resistance, oil resistance. the paint can be sprayed, but in the process of construction must be isolated from the fire, every 8 h brushing once per square metre of 400 ~ 500g, but this kind of brush type fireproof coating, cable in high density, long length, small space and other occasions inconvenient and time-consuming, labor intensity, influence construction period.
(3) fire proof package
domestic production of cable fire proof bags, according to the test is not less than similar products of japan's flame retardant properties. with a 1 mm thick fireproof bag, the cable is wound around the cable in a reciprocating way, and the horizontal arrangement is up to 7 layers. the model test shows that the effective flame retardant property is shown. this kind of material is especially good for local fire protection. can achieve a better fire prevention effect at a lower cost. in practical work, the application of fire retardant coating or fire proof bag, which can be used in the 2 ~ 3 m long section of the power cable joint and the adjacent cables, can reach the good fire prevention requirements.
(4) fire blocking material
sfd- ii, iii type fast solid fire blocking material is a kind of ideal cable through the hole and the firewall blocking material, it can effectively prevent the cable fire. the hole into adjacent rooms spread, the material blocking the fire performance is good, the basic heat, general block thickness cm can reach 7 ~ 10 fire retardant requirements. this material in the cable into the wall hole, terminal box holes, such as the use of a large number of holes, which is convenient, the effect is good, well received by the construction personnel. after many years of practice, it is proved that the safety and fire prevention effect is remarkable.
(5) blocking fire wall
the cable tunnel and the channel are divided into a plurality of blocking fire sections by blocking the fire wall, so as to reduce the scope of the accident and reduce the loss as much as possible. the fire wall generally adopts soft material to build, such as light block rock wool block, foam asbestos block, silicate fiber felt or flocculent such as mineral wool and silicate fiber, both for the packing sealing wall in the cable channel has been good enough, and can easily replace the cable in operation. the test result shows that about 240 mm thickness of the fireproof wall showed effective fire resistance ability of a barrier. in addition, the fireproof wall on both sides of the cable is close to 0.5 ~ 1 m, add fire paint or bag, does not need to set the channel fire door, which can effectively prevent the cable fire once through the flame and heat flow risk of door hole effect, solve the contradiction between the tunnel ventilation and fire prevention in normal operation.
(6) fire barrier
eg85-a, b, c type of fire resistant separator, used in plugging the cable through the hole, for the multi-layer cable layer separation and each layer of fire cover, with excellent characteristics.
the shaft sealing layer of eg85-a refractory plates and refractory materials, not only to meet the fire resistance, and satisfy the bearing load of inspection personnel, but also easy to add this type of replacement of cables, fireproof partition board used in the large external bear large hole plugging.
eg85-c type fire resistant separator, mainly used for cable fire protection cover, also can be used as a multilayer cable layer separator, which has the characteristics of light weight, thin shape, high strength, convenient cutting and drilling, corrosion resistance and so on.
eg85-b type fire separator is suitable for the small holes with different shapes, which can be used as the separation between the multilayer cable layer, but in the practical application. found that the strength is not high, can not cut the shortcomings of arbitrary.
(7) closed type light tank with difficult combustion
the cable of the high temperature pipeline and the part of the fire can be easily put into the closed box to form a fire blocking section. the hard burning groove box has the advantages of