Collection of common quality problems in building engineering: civil air defense engineering?

Civil air defense is referred to as "civil air defense" in China. It is to hinder the enemy's air-raid weapons, eliminate the consequences of air-raid, and mobilize and organize urban residents to "walk", "hide" and "disappear" air defense. Walking is evacuation. Before the war, organize the evacuation of urban population and the relocation of important economic transmission air strikes to avoid and reduce unnecessary losses during air strikes. Hiding is hiding. When the enemy carries out air raids on us, it will issue and transmit air raid warnings in time, and organize the people left in the city and important production and living materials to go underground to reduce losses; Elimination means eliminating the consequences caused by air strikes, organizing civil air defense professional teams and people to eliminate pollution, remove obstacles, rescue the wounded, repair communication, water supply, power supply and other systems, ensure the stability of urban life and production, and better support the anti-aggression war.

The importance of civil air defense engineering is self-evident, but in the actual construction process, various quality common faults can be seen everywhere. Today, share the common quality problems and prevention measures of electromechanical installation in civil air defense projects!

Construction Basis: The civil air defense project is constructed in accordance with relevant design and construction specifications such as Code for Design of civil air defence basement (GB50038-2005), Code for Construction and Acceptance of Civil Air Defense Projects (GB50 134-2004) and Standard for Quality Inspection and Evaluation of Civil Air Defense Projects. The reference atlas is the bound volume of 07FG0 1-05 series civil air defense atlas, building structure of air defense basement (07FJ02), installation of water supply and drainage facilities of air defense basement (07FS02), etc.

Common quality problems in water supply and drainage engineering

Phenomenon: There is no decontamination drainage and sewage collection well in polluted areas such as anti-virus channel, closed channel, decontamination room, simple decontamination room, diffusion room, valve room and poison filter room.

Analysis: It is stipulated in the specification that "the area and room that need to be washed outside the sealed door should be provided with a decontamination drain with a diameter of not less than 75mm", and the drain can be blocked by copper pipes and explosion-proof floor drains (as shown in the following figure). The areas and rooms that need to be washed outside the sealed door here mainly refer to the valve room, diffusion room, anti-virus channel, poison filter room, simple decontamination room and decontamination room.

Prevention and control measures: The above-mentioned polluted areas should be provided with drainage ditches and drains for collecting and washing sewage. The drainage pipe leads into a single washing sewage collection well. Some construction drawings leave out the flushing drains of some rooms, which should be set in place according to the requirements of the specifications, and special attention should be paid during construction.

Common quality problems in water supply and drainage engineering II

Phenomenon: the washing drain is higher than the terrace surface, which can not completely discharge the washing sewage or affect the opening of the sealed door.

Analysis: The elevation of decontamination drain should be the same as that of floor drain. Usually, the flushing drain pipe should be plugged with a copper plug. The top surface of the decontamination port should be 5- 10mm lower than the indoor floor, and the elevation of the copper tube sealing surface of the decontamination port should be 3-5mm lower than the civil completion surface. The indoor floor should be flooded to the decontamination drain, and the drainage pipeline should be provided with a fixed bracket and the slope should be controlled.

Prevention and control measures: The flushing drainage pipe should be embedded in place at one time in the binding stage of floor reinforcement, and wooden boxes and clinker sleeves are not allowed to be embedded. When using explosion-proof floor drain, it should be directly buried in concrete and not reserved.

Common quality problems in water supply and drainage engineering 3

Phenomenon: The flushing drainage pipe adopts cast iron drainage pipe or PVC drainage pipe.

Analysis: Because this kind of pipe is brittle, it is easy to break under the action of shock wave, and PVC pipe is easy to age under the action of light radiation. Therefore, DN80 hot-dip galvanized steel pipe should be used for this kind of pipeline crossing the protected enclosed area. Galvanized pipes should not be welded to avoid damaging the galvanized layer on the surface. If welding is really needed, secondary galvanizing should be done. The drainage pipes of civil air defense openings are mostly galvanized steel pipes, and steel bars or brackets are often directly welded and fixed with galvanized pipes during construction, which should be corrected.

Preventive measures: The construction unit shall strictly follow the requirements of the drawings, and the supervision unit shall check them one by one before concealment.

Common quality problems of water supply and drainage engineering IV

Phenomenon: When water supply and drainage, fire fighting, spraying and other pipelines pass through civil air defense emergency wall, closed wall and external wall, the embedded casing does not meet the specification requirements.

Analysis: When water supply and drainage, fire fighting, spraying and other pipelines pass through the above protective structure, waterproof wall-penetrating sleeves should be embedded, as shown in the following figure. Wall bushing generally has three forms:

(1) Ordinary wall bushing, without sealing rib and baffle, is mainly used for ordinary interior walls;

(2) Wall bushing with sealing rib. This kind of casing can be divided into two types: one is flexible waterproof casing, which is mainly used for external walls with high seismic requirements, and the other is rigid waterproof casing, which is mainly used for general external walls and closed walls without resistance requirements. The wall bushing extends out of the wall for more than 40 mm..

(3) Wall bushing with sealing rib and resistor. This is mainly used for adjacent walls, roofs and partitions of adjacent units with resistance requirements. There are sealing ribs in the middle of the wall-penetrating sleeve and fixed flanges on both sides. The sealing rib should be centered and the resistance plane should be flush with the finished surface of the structure. The width of the closed wing ring and flange is 100mm, and the thickness is not less than 10 mm ... The inner diameter of the wall-penetrating sleeve should be 30-40 mm larger than the outer diameter of the wall-penetrating tube, which is convenient for filling with sealing materials. It is incorrect to think that the casing diameter is 2 times larger than the working diameter.

Precautionary measures: Pay attention to the requirements of design drawings or reference atlas during construction. According to the different atlas, the practice of using sleeve with resistance sheet for external wall is also different. If the casing with resistance requirement is only made with resistance sheet on the side affected by resistance shock wave, attention should be paid to the difference during construction.

Five common quality problems in water supply and drainage engineering

Phenomenon: Leave a hole or make a hole at will to cross the airport fence, closed fence and ground.

Analysis: All water supply and drainage pipelines passing through the above-mentioned walls should be embedded with sleeves according to the requirements of drawings or atlas, and protected and tightly connected according to the requirements of specifications. Pipes unrelated to civil air defense projects shall not pass through civil air defense protection structures. According to the provisions of Design Code of civil air defence basement, only water supply, fire protection, heating and air conditioning refrigerant pipes with nominal diameters not greater than 150mm are allowed to pass if they must pass due to conditions, and valves are added inside the maintenance structure. The domestic sewage pipes, rainwater pipes and gas pipes of the superstructure should not pass through the civil air defense envelope.

Prevention and control measures: More basement structures should be built in houses and offices, and domestic sewage from residential buildings and rainwater from office buildings will be discharged through the basement. Considering that the superstructure is easy to be damaged in wartime, in order to ensure the overall strength and tightness of the envelope structure of civil air defense projects, pipes unrelated to the basement should be located as far as possible outside the protection scope of civil air defense projects, and civil engineering majors can take measures such as lowering the roof locally, setting up pipeline interlayers and setting up pipeline wells.

Common quality problems of water supply and drainage engineering VI

Phenomenon: fire hydrant box is embedded in the external wall, empty wall and closed wall of civil air defense.

Analysis: Because fire hydrant box is embedded in civil air defense exterior wall, airport wall and airtight wall, the thickness of the wall is reduced, which affects the protective ability and airtight performance of civil air defense projects.

Precautions: fire hydrant box is wall-mounted and surface-mounted.

Common quality problems of water supply and drainage engineering VII

Phenomenon: Explosion-proof valve is not set or set incorrectly.

Analysis: When water supply pipes, fire hydrant pipes, spray pipes, mechanical drainage pipes, ventilation pipes, oil pipelines, etc. When introduced from the entrance, the explosion wave valve should be set on the inner side of the retaining structure; When introducing from the shell, an explosion-proof valve should be set inside the shell; When crossing the partition wall of the protection unit and the protective enclosed floor of the upper and lower protection units, valves with nominal pressure not less than 1MPa shall be set on the pipelines on both sides of the protective enclosed partition wall and the protective enclosed floor. However, if the valve is not allowed to be installed due to the usual use requirements, a detachable flange short pipe can be installed at this position. When the ventilation pipeline passes through the enclosure structure of the air defense basement, an explosion-proof wave valve should be set on its inner side. Pressure relief pipes and vent pipes shall be equipped with explosion-proof valves at the inner side where the pipes pass through the outer wall or roof. When the drainage pipe for collecting fire fighting wastewater in the upper non-civil air defense area needs to pass through the civil air defense basement envelope, the floor drain should be explosion-proof and the explosion-proof wave valve should be set inside the pipeline passing through the civil air defense basement envelope.

Precautionary measures: all pipelines entering and leaving the civil air defense basement and the civil air defense enclosure structure passing through them should be protected and sealed, that is, explosion-proof valves should be installed inside the project; In addition, when the drainage pipeline embedded in the floor leads to the outside of the civil air defense project, explosion-proof valves should also be installed in the cleaning sump outside the project, and valve wells should be installed inside the civil air defense, and the protective valves should be gate valves. Pressure test records shall be made before installation of protection valve. Protective valves are installed on these pipelines to prevent shock waves, radioactive substances and other poisons from entering undamaged civil air defense projects along the pipelines.

Common quality problems of water supply and drainage engineering VIII

Phenomenon: There are no separate hangers and supports for fire valves, shut-off valves and protection valves.

Analysis: The working temperature of fire damper can reach above 280℃. Under the condition of high temperature flue gas, the distortion of the flue will directly affect the fire damper, so a separate crane and bracket are set to fix the fire damper to prevent its displacement and deformation. The closed valve body is heavy and needs an independent hanger to carry it. The main body of the protective valve is heavy, so it needs to be supported and fixed by an independent hanger in order to resist shock waves in wartime.

Prevention and control measures: during construction, strengthen the inspection of each process and the cooperation between disciplines, and carry out the construction in strict accordance with the requirements of the specification.

Common quality problems in water supply and drainage engineering IX

Phenomenon: replace explosion-proof floor drain and explosion-proof cleaning mouth with ordinary floor drain and ordinary cleaning mouth.

Analysis: Explosion-proof floor drain and explosion-proof cleaning port are wartime accessories with drainage function and protective sealing function; Ordinary floor drains and common cleaning openings do not have the function of protection and sealing, and will be destroyed instantly under the action of shock wave, which directly affects the safety of life and property. Construction and supervision personnel do not understand the protection requirements, nor are they familiar with explosion-proof floor drains and explosion-proof cleaning accessories, so it is easy to happen the above phenomenon. If there is no responsible work attitude, this phenomenon will also occur.

Prevention and control measures: construction and supervision personnel should know the protection requirements of civil air defense projects, be familiar with the correct methods of explosion-proof floor drain and explosion-proof cleaning mouth, and carry out construction as required.

One of the common quality problems in electrical engineering.

Phenomenon: The reinforcement of basement floor without pile foundation has not formed a grounding grid, and the door frame of protective sealing door has not been grounded, and the electrical grounding in various distribution boxes has not been directly introduced from the grounding grid.

Analysis: Every corner of the surrounding steel bars of the upper and lower floors of the civil air defense basement without pile foundation should be welded, one point every 5m along the width of the project and one point every 10-20m along the length to form a welded steel mesh. Welding shall be carried out at the lap joint of steel bars on the welded steel mesh. If the top and bottom plates are beam-slab structures, the main reinforcement (at least two) of the main girder should be welded with the transverse reinforcement of the plate every 5-8m, and the grounding resistance should be tested. If the grounding resistance value cannot be met, the grounding device should be added separately. The door frame of each angle steel sealed door is welded with 25×4 flat iron to the steel bar on the bottom plate, and at least one point of the steel bar is connected with the welded steel mesh. 40×4 flat iron is used for electrical grounding of various distribution boxes directly led from grounding steel mesh.

Precautionary measures: read the drawings carefully and be familiar with the grounding requirements of civil air defense projects.

Common faults of electrical engineering quality II

Phenomenon: The electrical pipeline is directly led from the man-made area to the non-man-made area, or the protective sealing measures are not taken between the protective units.

Analysis: The electrical lines passing through the emergency wall, sealing wall and emergency plug-in place in the bottom plate should be led to both sides of the wall, and sealed boxes should be installed in the wall. The two sealed boxes are connected by galvanized steel pipes with sealing ribs in the middle. The sealing rib shall be made of 3-4 mm steel plate and completely welded on both sides of galvanized pipe. When the diameter of steel pipe is less than 32mm, the sealed box can be replaced by 86-type junction box, and when the diameter of steel pipe is 32-50mm, the thickness should be 3. The two closed boxes should be staggered to ensure the thickness of the wall. The closed boxes cannot be used as lamps, distribution boxes and junction boxes.

Prevention and control measures: distinguish the difference between the operation technology of civil air defense electrical construction and the requirements of building engineering, and carry out the construction correctly according to the design drawings.

Common faults of electrical engineering quality III

Phenomenon: Thin-walled pipes are used as materials for electrical pipelines that need to be protected and sealed or are hidden in concrete walls.

Analysis: Steel pipes should be used for wire laying in peacetime and wartime projects. Thick-walled pipes (called thick-walled steel pipes with a wall thickness greater than 2mm) should be used for electrical pipelines buried in concrete, and galvanized steel pipes should be used for pipelines in closed sections.

Precautionary measures: protective and sealing measures must be taken for the closed section of electrical conduits laid in civil air defense projects, and the requirements of "protection" and "sealing" of civil air defense projects should always be kept in mind during construction.

The fourth common fault of electrical engineering quality

Phenomenon: The construction of cable tray and bus duct passing through civil air defense wall, sealing wall, floor slab and pre-war sealing place does not meet the specification requirements.

Analysis: all kinds of electricity (power, lighting, telephone, fire fighting, alarm, etc. ) Pipes and reserved pipes passing through the envelope shall be protected and sealed respectively. When the number of cables or wires in the project is large and concentrated, cable trays can be laid, but cable trays shall not directly pass through maintenance structures, protective airtight partitions and airtight partitions. Because the cable tray can't be completely protected and sealed when it directly passes through the above-mentioned wall, the cable tray should be disconnected when it passes through, and the cable should be laid through the pipe. Bushings are embedded in the enclosure structure, protective sealing partition wall and sealing partition wall, and there are sealing ribs in the middle of the bushings (Figure 25) to meet the requirements of protective sealing.

Preventive measures: The embedded sleeve shall meet the requirement that one sleeve should wear one cable, so that sealing measures can be taken after threading. When the bus duct is used in this project, the closed section of the bus duct should be densely insulated at the above wall.

Common faults of electrical engineering quality five

Phenomenon: When civil air defense works are used as personnel shelters, there are no call buttons, or all entrances and exits are set, or the call buttons are not directly buried in concrete.

Analysis: Call button is a means for external personnel to contact internal personnel in advance when they enter civil air defense. External personnel must enter the civil air defense through the gas prevention channel. Press the call button outside the protective seal door, and only with the permission of the internal personnel on duty can the personnel on duty open the door and let them enter the civil air defense. Therefore, the product will be directly embedded in the concrete wall as long as it is set on the wall outside the protective sealed door in wartime.

Precautions: Explosion-proof call buttons should be set at appropriate positions during construction, and it is forbidden to drill holes on the wall at will after completion.

Common faults of electrical engineering quality VI

Phenomenon: When laying the line, the embedded spare pipes for communication and alarm facilities in the future civil air defense basement were not fully considered, and holes were randomly drilled in the closed wall and adjacent walls after being put into use, which destroyed the protection and sealing performance of the walls.

Analysis: In order to consider the pipeline laying when communication, alarm and other facilities are added in the basement of civil air defense in the future, spare pipelines should be embedded in order to avoid drilling holes in the closed wall and empty wall in the future, which will damage the protection and sealing performance of the wall. Civil air defense projects should protect each person's entrance and connecting passage. Sealed doors and door frame walls of sealed doors should be embedded with 4-6 galvanized steel pipes with a diameter of 50-80mm as spare pipes, and sealing ribs should be set in the middle. The distance between the center of the pipeline and the angle steel of the wall, roof and door frame shall not be less than 100mm, and the nozzle shall be 70mm away from the structural wall.

Precautionary measures: the pipeline embedded in the hole should be embedded in place at one time according to the design drawings, and at the same time fully meet the opening and closing space of the civil air defense (closed) door without affecting the 90 opening angle of the civil air defense door.

The seventh common fault of electrical engineering quality

Phenomenon: The lighting circuit leading from the civil defense area to the non-human defense area is not fused in the civil defense area.

Precautions: In order to prevent outdoor lamps from being damaged during wartime air raid, indoor lighting is affected by short circuit of lighting circuit. Therefore, short circuit protection devices such as fuses or separate lighting circuits should be provided for the lighting circuit leading to the air defense door in the basement.

I believe that after the above introduction, everyone has a certain understanding of the collection of common quality problems in construction projects: civil air defense projects. Welcome to Zhong Da for more information.

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