Work instruction for wire and tube embedment
I. Work content
Prefabrication of junction box, measurement and alignment, template drilling, welding support, installation and fixation of junction box, pipeline laying and sealing protection.
Second, the construction preparation
1. Material preparation:
Before construction, according to the detailed construction drawings, count all kinds of materials and prefabricated components needed for each floor, and establish statistical tables to facilitate material supply and quota acquisition.
1. 1. The cast-in-place concrete structure shall be embedded with medium or above flame-retardant PVC conduits. Need good compression resistance and impact resistance; The pipeline should be flexible, not easy to break when bending, and have good resilience. Building electricians should use non-plasticized rigid flame retardant PVC pipes.
1.2. Conduit, junction box, connecting sleeve, lock nut, glue, etc. Matching products from the same manufacturer should be adopted. The height of the knock-out hole of the junction box from the box mouth should match the distance between the steel bar in the use place and the template. The inner diameter of the connecting sleeve and the locking nut should be closely matched with the outer diameter of the conduit.
1.3. The pipeline and its fittings shall be inspected when entering the site. The measured wall thickness of PVC pipe should be uniform, without deformation and bubble crack. , and require fire products inspection report and factory certificate, the oxygen index is greater than 27%. The junction box shall be smooth and level with complete opening. Tubes and junction boxes shall have clear manufacturer's name and trademark, specifications and models, and implementation standard numbers.
1.4. Other materials:
Nail, wire binding, adhesive tape, sawdust, paint
2. Machines and tools:
Hand drill, hole opener, cutting machine, saw blade, pliers, tape measure, spirit level, wire pendant, writing brush and red pencil. Technical preparation:
3. 1. Civil structure is the foundation of hydropower equipment and pipeline installation. Before construction, we should carefully check and thoroughly understand the dimensional relationship between civil structures and architectural drawings. If there are any unclear places or problems, please ask the civil engineer to solve them in time. 3.2. Before construction, technicians should comprehensively consider the system of civil engineering and hydropower equipment, draw detailed construction drawings, and ensure the positioning dimensions of various electrical junction boxes are accurate.
4. The basic operation process:
After the operation team enters the site, it should be given technical disclosure to familiarize it with the basic operation technology of PVC pipes.
4.1.Cutting of PVC pipe
Before piping, it should be cut according to the required length of each section of pipeline. Cutting can be cut by hacksaw, special pipe cutter, or by using grinding wheel cutter when prefabricating. No matter which method you use, you must do it in the end, and it is forbidden to break it back and forth by hand. The incision should be vertical, and the burr of the incision should be easy to clean.
4.2. Bending of PVC pipes
The flexibility of PVC pipe is very good, and it can be directly bent by bending spring at room temperature, which is relatively simple and easy. Insert the bending spring into the pipeline where it needs to be bent, hold both ends of the bending spring with both hands, move your knees slightly to the bending part, and simmer with both hands evenly to a slightly smaller angle. When you let go, the elbow will rebound to the required angle. One end of the bending spring should be tied with iron wire or string. When bending a long pipe, the bending spring is not easy to take out; After the elbow is completed, turn the bending spring counterclockwise to shrink its outer diameter, and at the same time pull it outward to take out the bending spring.
4.3. Connection of PVC pipes
Generally, PVC pipes are connected by sleeve. The outer diameter of the connecting pipe end is about 1 ~ 2, which must be cleaned. Glue is then applied and inserted into the sleeve to the center of the sleeve. The two pipes are closely aligned and kept for a period of time, so that they are firmly combined. The sleeve can be made of finished sleeve joint or larger PVC pipe. When making self-made casing, cut the large PVC pipe by 3 ~ 4 times of the outer diameter of the connecting pipe. The inner diameter of PVC pipe for casing shall be closely matched with the outer diameter of connecting pipe, and there shall be no gap.
5. Prefabrication:
During the construction of the main concrete structure, the embedded operation time provided by civil engineering is extremely limited. In order to cooperate closely with the civil engineering and complete the embedded work quickly, the prefabricated construction method must be adopted. Some operations must be moved to the ground floor for processing and prefabrication, and then taken to the operation floor for installation when embedded, so as to reduce the workload of the floor.
5. 1. Prefabrication of junction box
Switch box, socket box and lamp holder box can be divided into straight fork, curved fork, three fork and four fork according to different pipe inlet directions. The quantity required for each construction section shall be classified and counted, and prefabricated before embedding. During prefabrication, knock out the knock hole in the required direction and install the lock nut. Each lock nut mouth is sealed with paper and made into various types for embedding.
5.2. Elbow prefabrication
The installation height of ordinary socket is 0.3m, and the elbow from the floor to the socket can also be pre-bent according to a fixed length.
5.3. Prefabrication of straight pipe section
The installation height of the lighting switch box is1.4m. The pipeline leading from the switch box to the ground can be cut into short pipes according to its length.
5.4. Foam prefabrication
Due to the impact of concrete pouring, the height of the junction box in the wall will be depressed, so the method of secondary embedding can be adopted. First, bury a slightly larger piece of foam plastic and leave a hole in the junction box, and then install the junction box after the civil work is dismantled. This kind of foam can be prefabricated according to W300px×H500px, and the foam is wrapped with plastic tape to prevent damage.
5.5. Prefabrication of wooden cases
The wooden box embedded in the hole of the distribution box should be prefabricated in advance and the hole of the pipe should be drilled.
5.6. Precast support
In order to protect the steel door bracket used for the socket pipe bent from the ground, it should be prefabricated in advance and welded on the beam reinforcement in time.
6. Fuck oak parts
6. 1. In the construction of cast-in-place concrete structure, walls and columns are usually poured first, then beams and floors are poured, and finally masonry is built. Electrical pipes should generally be embedded in the wall columns and floors of cast-in-place structures, and the remaining pipe boxes should be connected during masonry construction. 6.2. When cooperating with the PVC electric tubes embedded in the civil wall column, it shall be carried out after the steel bar binding of the civil wall column is completed. Civil engineering should give the building elevation line and wall column template line, and check it.
6.3. When cooperating with the PVC electric pipes embedded in the civil floor, it should be carried out after the binding of the bottom reinforcement of the civil floor and when the gluten has not been bound. The building axis should be given in civil construction and checked correctly.
Third, the process flow
1. Embedded shear wall:
Prefabrication of junction box and pipe section-box fixing-pipeline laying-sealing protection
Measuring and setting out-→-┘
2. Embedded floor
Junction box and pipeline section-→┐┌→ Prefabrication of welding support
Measuring, setting out and positioning → drilling → box fixing → pipeline laying → sealing protection.
Fourth, the construction technology
1. Pay-off positioning
Switches, sockets and light boxes must be located in strict accordance with the actual drawings and specifications. The measurement and positioning of switch socket can be divided into three aspects: plane position, height and concave-convex distance from the wall. Install the junction box according to the design height of various electrical appliances. For the junction box on the shear wall, take the top 1250px marked in red on the civil column rebar as the benchmark, and at the same time, retest the elevation of each junction box with horizontal pipes. The plane position of the junction box must be determined according to the axis and rechecked by the civil wall line.
The plane position of the switch box, if the specific size is not clearly marked on the design drawing, ① the switch in the wall should be aimed at the light box.
② Generally, the switch at the door should be on the open side of the door, and the clear distance between the switch box and the door opening is 375px (500px if the door frame is added), as shown in figure 1.
③ If the crib is narrower than 925px, the switch is installed on the other wall of the corner, and the switch box is 500px away from the corner, as shown in Figure 2.
④ If the width of battlements is 37 ~ 1500px, the switch is set on the center line of battlements. ⑤ If the switch is at the outer corner, it is 500px away from the outer corner line, as shown in figure 1.
⑥ The light box of the wall lamp should be above 2.4m, and the PE line should be added below 2.4m. The wall lamp switch should be located directly below its vertical position.
2. Install the junction box
In order to achieve a good impression, the embedded position of the junction box must be accurate and tidy. Switch socket and must be installed and fixed according to the determined position, clamped with steel bars up and down, left and right, and welded on the vertical steel bars. Then use messenger wire to measure the concave-convex distance between the box mouth and the wall surface, adjust the box to be flush with the wall surface, and fasten it with iron wire.
drill
For the pipeline leading from the floor to the brick wall switch socket, it is necessary to drill holes in the beam template in advance. Before drilling, the exact position of the brick wall must be determined according to the architectural drawings and structural drawings to ensure that the drilling is within the scope of the brick wall.
4. Pipeline laying
General pipelines should be laid in the nearest direction in strict accordance with the design, so as to make the direction straight and reduce bending. However, it is forbidden to cross and overlap the three layers of pipes in the plate; The distance between two parallel PVC pipes should be greater than125px; ; The intersection angle between PVC pipes in the board must be greater than 45; The distance between the same PVC pipe and the other two pipes must be greater than 20d. If the pipeline laid in a straight line cannot meet the above requirements, it should be laid around the pipeline appropriately.
In any of the following circumstances, a junction box should be added in the middle: ① The pipe is not bent, and the pipe length exceeds 30m each time; (2) The pipeline has an elbow with a length greater than 20m；; (3) The pipeline has two elbows, each of which is longer than15m; ; (4) The pipeline has three bends, and the length of each pipe exceeds 8m.
The distance between the fixed points of PVC pipes is not more than 1m, and the distance between the end and the bending midpoint is not more than 0.5m
5. Product protection
5. 1. All upward nozzles and junction boxes buried in concrete must be sealed tightly to prevent sundries from entering the pipes.
5.2. The socket pipe bent from the ground to the brick wall is made into a portal bracket with steel bars, welded and fixed on the beam bars, extending out of the floor for about 250px, and then the PVC pipe is bound on the bracket to prevent the PVC pipe from bending and breaking.
5.3.PVC pipe must assign personnel to be on duty, and strengthen protection during concrete pouring to prevent displacement or damage during vibration; The personnel on duty must take good care of the concrete until it is poured tightly, and shall not leave the post halfway. If the embedded pipe box is found to be damaged, it should be repaired in time.
Verb (abbreviation of verb) quality standard
1. Guaranteed project
The material, variety, specification, quality and applicable place of PVC pipes must meet the design requirements and construction specifications.
2. Basic projects
2. 1. The pipeline shall be laid and connected closely, the cutting fracture of the pipeline shall be smooth, the protective layer shall be greater than 15mm, the box body shall be set correctly and fixed reliably, the pipe shall be straight in the box, and the exposed length of the pipe in the box shall be less than 5mm. ..
2.2. The pipeline passes through the deformation joint with compensation device and can move freely; Through the building foundation and equipment foundation with casing protection.
2.3. The bending radius of concealed piping shall not be less than 10 times of the outside diameter of the pipeline; There should be no wrinkles, depressions and cracks at the bend, and the bending degree should not be greater than 0.1d.
2.4. The wire box shall not protrude from the wall, and the recessed wall shall not be greater than 5 mm. The switch socket box shall be in the same room, and its height difference shall not be greater than 5 mm; The height difference of switch socket boxes juxtaposed on the same wall should not be greater than 65438±0mm；;
Six, quality common fault and its prevention and control
1.After the PVC pipe is cut off, the fracture is irregular. When cutting PVC pipes, everything must be cut to the end with a saw blade or pipe. Don't break them by hand.
2. After the 2.PVC pipe was sawed off, the broken burr was not cleaned up. After the PVC pipe is sawed off, the burr should be scraped clean with a saw blade in time.
3. The PVC pipe joint is not tight and firm. The pipe diameter of casing should not be too large; Connected pipes should be closely aligned between sleeves.
4. Cracks and folds at the bend of 4.PVC pipe. High-quality pipes should be selected and bent in the right way.
5. The lock nut at the pipe box falls off or is disconnected. The stop should be inserted under the lock nut.
6. Rows of junction boxes are not in a straight line. Rows of junction boxes, cable positioning.
Seven. Safety requirements
In addition to the general safety rules and regulations, the following matters should also be paid attention to when cooperating with civil engineering embedment in the structural construction stage:
1, to prevent and avoid nail feet;
2. Don't stand under the hanging objects when the tower crane hangs objects to prevent falling objects from hurting people;
3. Pipes, etc. Can not be placed outside the frame to prevent falling;
4. When walking on the scaffold, avoid stepping on the probe plate;
5, limb homework can't step on empty;
6. Don't throw things down.
Eight, civilized construction
The working face should be cleaned at any time, and the waste and surplus materials should be transported to the designated stacking place downstairs.