Integrated wiring can be said to play an important role in the entire intelligent building, and with the development of intelligent buildings, the requirements and attention to integrated wiring are becoming more and more strict. So, what are the requirements for the protection of integrated wiring and cable laying? What problems should be paid attention to in the environmental protection of integrated wiring?
Integrated wiring and cable laying
1. What are the protection requirements for the laying of integrated wiring cables?
(1) Cable laying protection requirements for horizontal subsystems
1. Protection requirements for metal trays and plastic trunking
1.1. Protection requirements for overhead metal bridges
The metal bridge is required to be made of steel plates with a thickness of 0.5-1.5mm.
Metal bridges are divided into two types: trough bridges and ladder bridges. The trough bridge refers to a trough-shaped component formed by bending a whole steel plate, and the ladder bridge refers to a trapezoidal component composed of sides and several rungs.
The necessary accessories for metal bridges include tee, cross, bend, hanging bracket, etc. The function of the accessories is to fix or supplement the functional components of the straight line and the bend, which are necessary for the connection between the straight sections and between the straight sections and the bend. The support and hanger play the function of directly supporting the bridge. It includes support arm, column, column base, hanger and other fixed brackets.
The metal bridge should ensure that the surface is galvanized, painted, powder sprayed, hot-dip galvanized, nickel-plated zinc alloy purified or stainless steel. When using, choose the appropriate anti-corrosion treatment method for nickel according to the engineering environment, importance and durability. Generally, the galvanized cold-rolled steel bridge can be used in the environment with light corrosion; the bridge can be purified by nickel-plated zinc alloy in the environment with strong corrosion, or stainless steel can be used.
The installation of the trunking should be carried out simultaneously with the construction of other pipelines (such as air ducts, water supply and drainage pipes) after the civil engineering is basically completed, or it can be installed a little later than the construction of other pipelines. However, try to avoid installation after the decoration project is completed, otherwise it will cause difficulty in laying cables. The installation of the trunking shall meet the following requirements:
(1) The installation of the wire duct shall comply with the requirements of the construction drawing, and the left and right deviation depends on the environment, and the maximum shall not exceed 50mm.
(2) The deviation of wire groove levelness per meter should not exceed 2mm.
(3) The vertical trunking should be kept perpendicular to the ground, and the deviation of the verticality should not exceed 3mm without inclination.
(4) The trunking section and the inter-section are assembled with a joint connecting plate and then fixed with screws, and the screws should be tightened. The horizontal deviation of the splicing of the two wire troughs should not exceed 2mm.
(5) When the straight section bridge is produced over 30m or spans the building, there should be expansion joints. The connection should adopt telescopic connecting plate.
(6) The turning radius of the wire groove shall not be less than the maximum of the minimum allowable bending radius of the cable in the groove.
(7) The cover plate should be tightened. And to dislocate the cover slot.
(8) When laying metal trunking, brackets or hangers should be installed at the distance of 1-1.5m between the joints of the trunking, 0.5m away from the two ports of the trunking, and at the turning point. The support and hanger should be kept vertical, neat and firm, without skew.
(9) In order to prevent electromagnetic interference, it is advisable to use braided copper tape to connect the trunking to the grounding device in the equipment room or floor wiring room it passes through, and maintain a good electrical connection.
(10) Different types of cables are laid in the metal trunking, and should be laid out in the same groove compartment (separated by a metal plate).
1.2. Protection requirements for embedded metal bridges
1) Pre-embedded wire troughs in buildings should be set in a single layer, the height of the section of the wire trough should not exceed 25mm, and the total width should not exceed 300mm.
2) When the direct buried length of the wire trough exceeds 30m, or when the wire trough route crosses or turns, a wire box should be set up to facilitate cable routing and maintenance.
3) The cable-passing box cover should be able to be opened and flush with the ground, and the box cover should have waterproof function.
4) The junction box and junction box cover should be able to withstand pressure.
5) The cables from the metal trunking to the information socket junction box should be laid with metal hoses.
1.3 The grounding of the metal bridge should meet the design requirements.
1.4 When the metal bridge passes through the wall or floor, fire prevention measures should be taken.
1.5. The protection requirements for plastic trunking are as follows:
There are various specifications of plastic trunking. The laying of plastic troughs is similar to metal troughs, but there are differences in operation. There are three ways: using hangers or bracket bridges on the ceiling; using bracket bridges outside the ceiling; using outside the ceiling Brackets plus matching grooves are laid.
When a bracket is used, a bracket is generally installed at about 1 m. When fixing the groove, the fixing point is generally installed at about 1m. The fixed point refers to the place where the groove is fixed. According to the size of the groove, it is recommended:
25mm×20—30mm slot, one fixing point should have 2—3 fixing screws, and they should be arranged horizontally;
For a slot with a size of 25mm×30mm or more, one fixing point should have 3-4 fixing screws in a trapezoidal shape, so that the stress points of the slot are distributed.
In addition to the fixed point, two holes should be drilled every 1m, and the twisted pair should be inserted. After the wiring is completed, the twisted pair should be bundled.
2. Protection requirements for metal pipes and PVC pipes
2.1 Processing of metal pipes
(1) Metal tube cutting wire
When piping, the pipe should be cut according to the actual required length. Hacksaw, pipe cutter or electric pipe cutter can be used to cut the pipe. Gas cutting is strictly prohibited.
Threading can be done manually or by using an electric threading machine. After threading, the nozzle should be cleaned at any time, and the burrs on the end face and inner wall of the nozzle should be smoothed with a file to keep the opening smooth, so as not to cut the cable insulation sheath.
(2) Bending the metal tube
Elbow should be minimized when laying metal pipes. There should be no more than 3 elbows for each metal pipe, no more than 2 right-angle elbows, and no S-bends. Too many elbows will make it difficult to pass cables.
No bends are allowed for cables with larger cross-sections. When the actual construction cannot meet the requirements, a pipe with a larger inner diameter can be used or a cable box can be set up in an appropriate position to facilitate the penetration of the cable.
2.2 Connection of metal pipes
The connection of metal pipes generally adopts segment socket or pipe joint thread connection. No matter which connection is used, the connection should be firm and the two pipe ports should be aligned with good sealing. The length of the socketed segment casing or threaded pipe joint shall not be less than 2.2 times the outer diameter of the metal pipe.
After the metal pipe enters the junction box of the information socket, the buried pipe can be fixed by welding, and the exposed length of the pipe opening into the box should be less than 5mm. The exposed pipe should be fixed with a lock nut or a pipe cap, and the exposed lock nut has 2 threads. - 4 buckles.
The position of the metal pipe orifice leading to the wiring room should be easy to connect with the cable. The nozzles of metal pipes laid side by side should be arranged in an orderly manner, which is easy to set apart.
2.3 Metal pipe protection requirements
(1) The surface of the pipe should not be perforated, cracked and obviously uneven, and the inner wall should be smooth and no rust is allowed. Pipes with sufficient strength should be used in places susceptible to mechanical damage and when directly buried in places with greater stress. Preservatives should be applied to the peeling parts of the zinc layer of the galvanized pipe to increase the service life.
(2) In order to prevent the cable from being scratched when passing the cable, the nozzle should be free of burrs and sharp edges. In order to reduce the shear force on the cable at the nozzle of the directly buried pipe when it sinks, the metal nozzle should be made into a trumpet shape. After the metal pipe is bent, there should be no cracks and obvious concave phenomenon. If the degree of bending is too large, the effective diameter of the metal pipe will be reduced, and problems such as difficulty in laying cables will easily occur.
(3) For metal pipes laid in concrete and cement, ensure that the foundation is solid and flat, and there should be no subsidence, so as to ensure the safe operation of cables after laying. The inner diameter of the metal pipe pre-buried in the middle of the wall should not exceed 50mm, the diameter of the pipe in the floor should be 15-25mm, and a hidden wire box should be set at 30m of the straight pipe. The buried depth of metal pipes between buildings should not be less than 0.8m; when laid under the sidewalk, it should not be less than 0.5m. The bending radius of the metal pipe shall not be less than the minimum allowable bending radius of the cable to be inserted.
The turning angle of the dark pipe should be greater than 90 degrees. When matching: generally not less than 6 times the outer diameter of the pipe, when there is only one bend, it may not be less than 4 times the outer diameter of the pipe; the whole row of steel pipes should be bent into concentric circles at the bend.
Concealed matching: should not be less than 6 times the outer diameter of the pipe, and should not be less than 10 times the outer diameter of the pipe when laid underground or in a concrete floor. The turning angle of each hidden pipe on the path should not be more than 2, and there should be no S-bend. When the length of the pipe section with elbow exceeds 20m, a pipeline junction box device should be installed;
When there are 2 bends, no more than 15m should be set through the junction box. The mouth of the dark pipe should be smooth and protected by a mouth guard, and the extension of the mouth should be 25-50mm.
(4) Metal pipes should have a drainage slope of not less than 0.1%.
(5) Pull wires or pull wires should be placed in the metal pipe.
(6) Both ends of the metal pipe shall be marked to indicate the initial length of the building, floor and room.
(7) The following requirements should be met when the metal pipe is laid openly: the metal pipe should be fixed with clips. This fixing method is more beautiful, and it is easy to disassemble when it needs to be disassembled. The spacing between the support points of the metal pipe shall be designed in accordance with the regulations when required. If there is no design requirement, it should not exceed 3m. At 0.3m from the junction box, fix the pipe with a pipe clamp. Where there is an elbow, both sides of the elbow should also be fixed with pipe clamps.
(8) When the optical cable and the cable are laid in the same pipe, the plastic sub-pipe should be preset in the dark pipe. Lay the fiber optic cable in the sub-pipe so that the fiber optic cable and the cable are armed separately. The inner diameter of the sub-tube should be 2.5 times the outer diameter of the optical cable.
2.4 Protection requirements for PVC plastic pipes
The construction requirements of the PVC pipe are the same as those of the metal pipe. Generally, the wire groove is buried in the working area. Two points should be paid attention to during operation. When the pipe is turned, the bending radius should be large to facilitate the threading. There should not be too much threading in the tube, generally more than 50% of the space should be left.
3. Network floor cable laying protection requirements
(1) It is required to use metal materials, the cavity of the bare board is filled with cement, and the multi-point welding is formed. The trunking cover shall be openable, and the trunking shall communicate with each other. There should be a cable outlet that can be arbitrarily matched with the common floor and the cable outlet floor.
(2) The width of the main trunking is determined by the width of the network floor, generally it should not be about 200mm, and the width of the branch trunking should not be less than 70mm.
(2) Trunk subsystem cable laying protection requirements
1. Cables should not be placed in elevators or water supply, gas supply, heating pipeline shafts, nor should they be placed in strong electricity shafts.
2. The trunk channel should communicate.
(3) Cable laying protection requirements for building complex subsystems
1. There are usually four ways to lay cables between buildings: underground pipelines, tunnels, underground direct burial and overhead laying. At present, underground pipeline laying is the most widely used method. When laying cables, avoid other cables in the pipeline, and consider the influence of the number of bends in the pipeline and the outer diameter and weight of the cables on the cable laying.
2. The connection and sealing of pipeline cables shall strictly comply with the construction specifications and operating procedures of the communication industry issued by the Ministry of Information Industry.
2. What issues should be paid attention to in the environmental protection of integrated wiring
First, we are using the network composed of the integrated wiring system to prevent electromagnetic pollution caused by radio frequency from affecting the normal operation of other surrounding networks.
With the rapid development of the information age, various high-frequency communication facilities continue to appear, and the influence of electromagnetic radiation and electromagnetic interference between them is becoming more and more serious. In foreign countries, electromagnetic influence has been regarded as a kind of environmental pollution, and special institutions have been established to manage telecommunications and electronic products, and to formulate electromagnetic radiation limit standards to control them.
For integrated wiring system engineering, there is a similar situation. When applied to computer networks, the transmission frequency is getting higher and higher. If the intensity of electromagnetic radiation is not limited, it will cause mutual influence. Therefore, the specification stipulates that the network composed of the integrated wiring system should prevent the electromagnetic pollution generated by the radio frequency from affecting the normal operation of other surrounding networks.
Second, when laying cables or optical cables in flammable areas and building shafts, fire-resistant and poisonous cables should be used; flame-retardant wiring equipment should be used between adjacent equipment, and ordinary cables or optical cables through steel pipes can be used. Outer jacket.
Regarding the promotion and application of fire-proof and anti-virus cables, considering the cost of the project, there is no large-scale protest, but it is limited to use in flammable areas and building shafts, and the wiring equipment should also be flame-retardant. If the price of fire-proof and anti-virus cables drops in the future, it may not be impossible to appropriately expand the use area. In case of fire, this kind of cable will reduce the emission of harmful gases, which will play a good role in evacuation of people.
What are the protection requirements for integrated wiring and cable laying? I believe you have already answered this question. From the above, we can clearly understand how to choose a good integrated wiring product in the integrated wiring, and also know what we need to pay attention to when laying and protecting the integrated wiring cable.
