1. Quality control in the construction preparation stage
1. Before starting construction, be familiar with the drawings, participate in the design disclosure, understand the characteristics of the project and the quality requirements of key parts (especially the parts with protective sealing requirements).
2. Identification of materials, devices and equipment required for electrical installation engineering.
The materials, devices and equipment required for the project shall be determined by the supervision. For materials, devices and equipment that do not meet the quality requirements, the production or supplier should be required to return and replace in time.
3. The main electrical materials and equipment used in the project should be filled in by the contractor when entering the site, and the "Material/Structural Accessories/Equipment Inspection Form" should be attached, and the approval certificate, factory certificate, material certificate (inspection report), commodity inspection certificate and other materials should be attached. The supervisor approves whether it can be entered and whether it can be used in the designated engineering part.
4. Before construction, focus on checking the wire model and specifications used in the wiring, whether it meets the design regulations, the minimum section of the conductor core of different laying methods should comply with the provisions of the construction specification, and the section is too small to cause hidden dangers. The core wire of the cable and conductor should be copper core wire.
2. Matters that should be paid attention to before the joint review of construction drawings and construction
1. Material selection.
The internal environment of the civil air defense underground project is humid, and the electrical equipment and materials should be selected with products with better moisture-proof performance.
2. About the power supply
(1) For civil air defense projects with imminent blocking entrances and exits, the power inlet line of the project shall not enter from the imminent blockage area, but shall enter through the wall, sagging beam or roof plate embedded protective sealed box or closed casing.
(2) For basements where there is no regional power supply to lead, the power supply line and pipe and the installation location of related equipment should be reserved. The power supply of the power system and the power supply in the area are introduced into the basement, and there should be a manual switching device to ensure a smooth conversion in wartime.
(3) Transformers, circuit breakers, capacitors and other high and low voltage electrical equipment installed in the air defense basement should use oil-free and moisture-proof equipment; The generator set of the internal power supply should use diesel generator set, and it is strictly forbidden to use gasoline generator set.
(4) The following projects should set up diesel power stations within the project: central hospital, emergency hospital; The total construction area of air defense basements such as ambulance stations, air defense professional team projects, personnel shelter projects, and supporting projects is greater than 5,000 square meters.
3. Power lines and laying
(1) Weak current lines (telephone, communication, monitoring, security, fire alarm, etc.) can be used to enter and exit the civil air defense project, but the method of dark pipe encryption and closure must be adopted.
(2) When the cable tray passes through the wall and plate with protection and sealing requirements, it should be disconnected in the middle, and the cable pipe should be used for the disconnection, and the protective sealing treatment should be done; Branch cables should not be used as much as possible to cross walls and plates with protection and sealing requirements (sealing treatment is difficult).
(3) When the project uses busway, the closed section of the closed dense insulated busway should be used at the enclosure structure, empty wall, protective closed partition wall, and closed partition wall. Due to the small number of busway manufacturers and the incomplete product specifications (the maximum current is 1600A), it is recommended that the power supply enter or pass through the civil air defense area preferably using cables.
(4) Installation of cables and wires
A. When cables and wires pass through the closed wall short pipe, the water and debris in the pipe should be removed. The two ends of the tube should be filled with a closed material, and the packing should be fixed and dense.
B. When the cable tray passes through the wall and plate with protection and sealing requirements, it should be disconnected, and the cable pipe should be used for the disconnection, and the protective sealing treatment should be done, and there should be no joints in the box.
C. Civil air defense projects combining peacetime and wartime, the conductor should be laid with steel pipes. Steel pipes with a wall thickness greater than 2.5mm should be selected for buried in steel bars and concrete wall panels, and galvanized steel pipes should be used in the contaminated area.
D. Fire pumps, smoke exhaust fans, fire valves and other fire fighting equipment, emergency lighting wires or cables should be selected flame retardant products.
E. Fire linkage control, automatic fire extinguishing control, communication, emergency lighting and emergency broadcasting and other lines, should be protected by steel pipes, and should be secretly applied in the non-combustion body structural layer, the thickness of the protective layer should not be less than 30mm, when it must be applied openly, fire protection measures should be taken on the metal pipe to enhance the fire ability of the pipe and improve safety.
F. The wartime distribution circuit from the low-voltage distribution room to each protective unit shall be independent. When crossing other protective units, there should be protective measures within the crossing protective unit.
G. Embedded wartime electrical backup using hot-dip galvanized steel pipe with a wall thickness of not less than 2.5mm.
4. Electric lighting
(1) Each protection unit should be connected to external and internal electricity, and set the main switch of the incoming line and the internal and external power transfer switch. The distribution box is set up in the duty room or chemical protection communication room in the clean area. When there is no indoor cleaning area such as the shelter department and car garage of the professional team, the distribution box can be installed in the contaminated area. All kinds of power distribution boxes, lighting boxes and control boxes in the air defense basement shall not be embedded in the outer wall, air wall, protective closed partition wall, and closed partition wall. If it must be set, it should be wall-mounted exposed.
(2) The ventilation signal setting should comply with the regulations; The outside of the closed door of the wartime entrance and exit of the protective unit should be set with a call signal button with protection capability; Lamps should use light weight wire crane or chain hanging lamps and bayonet lamps; Generally, the continuous power supply time of evacuation lighting should not be less than 30min, and the continuous power supply time of the first-level load in wartime is greater than the protective isolation time.
(3) When the lighting power circuit led from the protective area to the non-protective area is used in the protective area, when the lamps in the protective area and the non-protective area share a power circuit, a short-circuit protection device should be set on the inside of the protective closed door and the inside of the imminent blockage, or a separate circuit power supply should be set for the lamps in the non-protective area.
(4) Wartime safety exits that are not used as evacuation passages in peacetime shall be set in accordance with the specifications. In order not to mislead the peacetime evacuation escape, the wartime connection can be turned off in peacetime.
5. Grounding
(1) The structural steel mesh should be used as a natural grounding body, and when the grounding resistance value cannot meet the requirements, a grounding device should be added indoors or outdoors.
(2) When using structural steel mesh as a grounding body, the intersection of longitudinal and horizontal steel bars should be welded. The connections of all grounding devices must be firm and reliable.
(3) The protective wire (PE) should be connected to each grounding body and ensure a good electrical path, and the protective trunk should use galvanized flat steel not less than 25mm×4mm or round steel with a diameter of not less than 12mm; The protective branch line should use 25mm ×3mm galvanized flat steel. On the protective wire (PE), it is strictly forbidden to set switches or fuses.
(4) Indoor protective grounding trunk, grounding trunk or general grounding terminal of artificial grounding pole of electrical installation, indoor public metal pipes (such as ventilation pipes, water supply pipes, cables or wire threading pipes), metal components in the building structure (such as protective closed doors, closed doors, metal door frames of explosion-proof valves, imminent blocking, etc.), indoor electrical equipment metal shells, cable metal outer protective layers, etc.
(5) Fuel facilities should be made anti-static grounding.
6. Diesel power station
(1) Gasoline has greater volatility, and the use of gasoline engine sets in underground civil air defense projects is prone to fire, so from safety considerations, the generator set should use diesel generator sets, and it is strictly forbidden to use gasoline generator sets.
(2) Peacetime and wartime conversion requirements for diesel power stations: the diesel power stations of central hospitals and emergency hospitals should be installed in place at peacetime; In addition to the unit usually not to be installed in the Class A air defense basement, other ancillary equipment and pipelines should be installed in place. The unit should complete installation and commissioning within the 15-day conversion time limit; The design of the Class B air defense basement is in place, and the foundation, hook, pipe frame and embedded pipe of the diesel generator set and ancillary equipment are reserved according to the design requirements, and the installation and commissioning are completed within the 30-day conversion time limit.
(3) According to the calculation of wartime load, when the capacity is less than 120kW, the diesel unit of the mobile power station is more reasonable to choose according to 120kW. Rich capacity can be considered as an area power source for other guard units.
3. Quality control during construction and installation
1. Quality control of grounding device installation engineering
(1) Before construction, check that the dimensions of hot-dip galvanized flat steel and round steel used in the grounding body must meet the design requirements. According to the requirements, the general material specifications are: round steel diameter≥ 12mm; Flat steel cross-section≥ 4mm×25mm.
(2) Ensure that the branch wire connected to the electrical equipment and other non-live metal parts that can be removed to the ground (zero) is directly connected to the grounding trunk, and make a hidden project acceptance record.
(3) The grounding network makes full use of structural steel bars as a natural grounding body, and checks whether the welding lap length of steel bars, flat bars and round bars in the grounding body meets the provisions of the current "Civil Air Defense Engineering Quality Inspection and Evaluation Standards" to ensure that there is a good electrical path.
(4) The grounding resistance of the grounding device must meet the design requirements, and the "shake meter" is used to measure and record.
(5) The laying of grounding (zero) wires shall be fully inspected in accordance with the requirements of the current "Civil Air Defense Engineering Quality Inspection and Evaluation Standards".
(6) The grounding (zeroing) branch laying of electrical equipment, appliances and non-live metal parts shall be carried out spot checks in accordance with the requirements of the current "Civil Air Defense Engineering Quality Inspection and Evaluation Standards".
(7) Check whether the protection wire (PE) is connected to the grounding body and ensure that there is an intact electrical path. When the phase line cross-section is 16mm² and below, the cross-section of the grounding wire should be the same as the phase line cross-section.
(8) If the base of the power distribution cabinet installed on the ground is a section steel foundation, whether the foundation cabinet and the foundation section steel have obvious reliable grounding.
2. Quality control of electrical piping engineering
(1) According to the requirements of civil air defense engineering, when cables and wires are concealed pipes passing through the civil air defense enclosure structure, air wall, protective closed partition wall or closed partition wall, closed boxes should be set on both sides of the wall. There must be no terminals inside the box. The closed box should be sealed after threading, and a cover plate made of 3mm galvanized steel sheet should be added. When the cable tray passes through the wall and plate with protection and sealing requirements, the closed casing should be embedded in the wall and plate.
(2) Check whether the piping is laid in accordance with the provisions of the construction code. Concealed piping laying requires a concealed project acceptance record. The following issues should be paid attention to in piping laying inspection:
A. There must be a compensation device at the place where the pipeline passes through the settlement joint and deformation joint;
B. The bending radius of the wire protection pipe should comply with the regulations, and there should be no wrinkles, depressions and cracks in the bend;
C. The additional junction box or pull box is arranged reasonably and the position is correct;
D. The wire protection pipe entering the floor-standing distribution box is arranged neatly, the pipe mouth is 50~80mm higher than the basic surface of the distribution box, and the piping into the box, box and cabinet screen must be mechanically opened;
E. In the TN-S, TN-C-S system, when the metal wire protection pipe, metal box (box), plastic wire protection tube, plastic box (box) are mixed, the metal wire protection pipe and the metal box (box) must have a reliable electrical connection with the protective ground wire (PE line);
F. The electrical pipeline embedded in the bottom plate shall not be directly introduced into the non-civil air defense area from the civil air defense area, and when it must be introduced, it shall be protected and sealed on the wall of the closed partition wall and the empty partition wall;
G. The electrical piping in the ceiling shall not be fixed to the hanger or keel of the flat roof.
(3) Check whether the steel pipe laying complies with the provisions of the construction specification. Embedded electrical pipelines, including dark piping, require concealed engineering acceptance records. The following issues should be paid attention to in the steel pipe laying inspection:
A. The wire protection pipe buried directly in the ground must meet the material and anti-corrosion requirements stipulated in the specification;
B. The steel pipe should not have defects such as flattening and cracks, iron filings and burrs in the pipe;
C. The connection of steel pipe must comply with the provisions of the specification, metal steel pipe is strictly prohibited to be welded with opposite mouth, galvanized and steel pipe with wall thickness less than 2mm shall not be casing fusion welded connection;
D. The connection between the steel pipe and the box (box) or equipment must comply with the provisions of the specification;
E. The connection of the steel pipe should comply with the provisions of the specification, when the non-galvanized steel pipe is connected by thread, the two ends of the connection are welded across the grounding wire, when the galvanized steel pipe is connected by thread, the two ends of the connection are fixed with a special grounding card to fix the jumping grounding wire, and the wire between the two cards is a copper core soft conductor, and the cross-sectional area is not less than 4mm²;
F. The part where the electrical appliance is installed should be equipped with a junction box;
G. The steel pipe is arranged neatly, the fixed electrical spacing is uniform, and the setting of the steel pipe pipe card needs to comply with the provisions of the specification.
(4) Check whether the metal hose laying complies with the provisions of the construction code. The following issues should be paid attention to in the metal hose laying inspection:
A. The length of the metal hose laying meets the provisions of the specification, and the length of the hose is not more than 0.8m in the power engineering and not more than 1.2m in the lighting project;
B. The metal hose cannot be untwisted, loose, and there are joints in the middle, and special joints must be used when connecting with equipment and appliances;
C. Whether the metal hose without insulation is reliably grounded.
3. Quality control of closed junction box installation
Weak current lines generally use multiple wires to pass through the wall and plate with protection and sealing requirements, because multiple wires will have gaps together, it is not suitable for sealing and plugging. In order to achieve the same sealing effect, the mode of closed box is adopted. In order to ensure the sealing effect, the pipe diameter shall not exceed 25mm, the purpose is to control the number of wires in the tube, because there are too many threads in the tube, which will affect the sealing effect.
The key points of the control are as follows:
(1) All embedded electrical sealed boxes should be found;
(2) The closed junction box and cover plate should be made of hot-dip galvanized steel plate, with a thickness of ≥ 3mm;
(3) When the cable or wire dark piping passes through the wall or board with protection and sealing requirements, a wire sealing box should be set up on both sides of the wall or on the upper and lower sides of the board, and there should be no terminal head in the box, and the closed box should be sealed and covered after threading.