Through a week's installation and construction practice, I have a deeper understanding of the knowledge in many textbooks in practice, which makes the installation project worthy of the name. What impressed me most was the trip to Washington Square and the Construction Committee Building. People can deeply feel that the new building attaches importance to fire protection, so I have a further understanding of the installation of fire-fighting equipment, especially the installation of indoor fire-fighting pipes, through the explanations of teachers and on-site technicians. The installation of indoor fire fighting system is mainly the installation of pipes and equipment for indoor automatic sprinkler system and fire hydrant system.
Before the construction of fire protection system, the material requirements are mainly to select fire sprinkler pipes according to the design requirements. Galvanized carbon steel pipes and fittings are generally used. Galvanized evenly inside and outside the pipe wall, without corrosion and flying thorn, parts are not biased, square buckle, incomplete thread and cold angle. Fire hydrant system pipe should be selected according to the design requirements, generally using carbon steel pipe or seamless steel pipe, and the pipe should not be bent, corroded, double skinned and uneven. The specifications and models of the main parts of the fire sprinkler system, such as alarm valve, action valve, control valve, delay device, water flow indicator, water pump adapter, etc., should meet the design requirements, with complete accessories, regular pouring, smooth surface without cracks, flexible opening and closing, and product factory certificate. The specification, model and working temperature of the nozzle should meet the design requirements, with neat appearance, complete thread, no damage and looseness of the temperature sensor package, and no loss and looseness of the fusible piece. Have the product factory certificate. The specifications and models of fire hydrant box should meet the design requirements, and the surface of the box should be smooth and bright. The metal box has no rust and scratches, and the door is flexible to open. This box is square with complete accessories. Plug valve has regular appearance, no crack, flexible opening and closing, tight closing, intact sealing packing and factory certificate. The main installation machinery includes: threading machine, grinding wheel saw, bench drill, electric hammer, hand grinding wheel, hand electric drill, electric welding machine, electric pressure test pump and other machinery. Set of wire plates, pipe tongs, vises, pressure tongs, chain tongs, hand hammers, hacksaws, wrenches, nail guns, chains, electric welding and other tools.
The operation process flow is as follows: installation preparation → main pipeline installation → alarm valve installation → riser installation → installation of spray layered main branch pipe, fire hydrant and branch pipe → installation of water flow indicator, fire pump, high-level water tank and water pump adapter → pipeline pressure test → pipeline flushing → installation of spray branch pipe (system comprehensive pressure test and flushing) → installation of throttle device → installation of alarm valve fittings, fire hydrant fittings and spray head → system water commissioning.
As we know, the main preparations before installing fire fighting equipment are: familiar with drawings carefully, selecting materials according to construction scheme, technology and specific measures of safety disclosure, measuring dimensions, drawing sketches and prefabricating. Check the relevant professional drawings, check whether the coordinates and elevations of various pipelines are crossed or improperly arranged, and solve them with designers in time. Check whether the embedded parts and reserved holes are accurate. Check whether pipes, fittings, valves, equipment and components meet the design requirements and quality standards. It is necessary to arrange a reasonable construction sequence to avoid the interference of engineering cross-operation and affect the construction.
Installation of main pipeline: Generally, the spraying pipeline needs galvanized pipe fittings (if the diameter of the main pipeline is more than 100mm, if there is no galvanized pipe fittings, it shall be connected by welding flange, marked after pressure test and galvanized shall be removed). Carbon steel pipe or seamless steel pipe shall be selected for the pipeline that needs to be galvanized, and oil shall not be brushed and the pipeline shall not be polluted before galvanized. Pipes that need to be dismantled and galvanized should be arranged for construction first.
The length of each pipe connected by the flange of the main spray pipe shall not exceed 6m, and several pipes can be connected together in the straight pipe section, and installed by inverted chain, but it should not be too long. After the pipes are straightened, they should be hoisted in sequence. When hoisting, one end of the pipeline should be hoisted first, and then the other end should be hoisted after it is stable. When the pipeline is connected with the fastening flange, check whether the flange end face is clean, and use 3~5mm rubber gasket. The specifications of flange bolts shall conform to the regulations. Fastening bolts should be tightened at the most unfavorable point first, and then tightened symmetrically in turn. Flange interface should be installed in an easy-to-disassemble position. The main installation of fire hydrant system should use pipes according to the design requirements, and carbon steel pipes or seamless steel pipes should be selected according to the pressure requirements. Before the pipeline is welded, the floating rust, dirt and grease at the joint should be removed. When the wall thickness is ≤4mm and the diameter is ≤50mm, gas welding should be adopted; When the wall thickness is ≥4.5mm and the diameter is ≥70mm, electric welding should be adopted. When welding pipes with different diameters, if the difference between the two diameters does not exceed 15% of the small diameter, the necking at the end of the large pipe can be butt welded with the end of the small pipe. If the difference between the two pipes exceeds 15% of the small diameter, the short reducing pipe shall be welded. Branch pipes shall not be welded at the butt welds of pipelines, and joints shall not be installed at the supports and hangers. There should be no interface (threaded connection or welding) at the pipe wall. Anti-freezing measures should be taken when the pipeline passes through the expansion joint. When welding carbon steel pipes, the welds should be staggered and oriented in the direction of easy observation and maintenance. When welding the pipeline, spot weld at least three points, then check the position, direction and diameter change of the reserved opening, straighten and align it, then weld, tighten the clamping piece and remove the temporary fixing piece.
Installation of alarm valve: it should be located in an obvious and easy-to-operate position, and the height from the ground is about1m. The ground at the alarm valve should be drained, and the ambient temperature should not be lower than +5℃. The alarm valve shall be assembled according to the product specification and design requirements. The control valve shall be equipped with an indication device for opening and closing, and the valve shall be in a normally open state.
Installation of fire sprinkler and fire hydrant riser: When the riser is concealed in the shaft, install clips on the embedded iron parts in the tube well to fix it, and the support and hanger at the bottom of the riser should be firm to prevent the riser from falling off. When the riser is installed, holes should be reserved on each floor, and the riser can be penetrated with the structure to reduce the riser interface.
Installation of fire sprinkler layered main pipe: the reserved openings of pipeline branches should be prefabricated before hoisting. Threaded connection, the reserved port should be located by tee. When welding, a wrought iron pipe hoop can be welded at the opening of the main pipe, straightened and hoisted. All reserved ports are temporarily blocked. Pipes that need to be galvanized should be reinstalled after pressure testing, dismantling and galvanizing, and then other pipes should be installed. The installation of pipes in the corridor ceiling should be coordinated with the location of ventilation pipes. For the connection of spray pipes with different diameters, sleeves should not be used. Instead, variable-diameter hoops should be used, and reducing elbow should be used instead. There should be at most one sleeve on the tee and at most two sleeves on the cross. When conditions permit, the upward nozzle and the main branch pipe can be installed in turn. Upward nozzles should also be installed in other locations where it is difficult to operate after pipeline installation.
Installation of fire hydrants and branch pipes: fire hydrant box should meet the design requirements (wooden, iron, aluminum alloy, etc.). ), and the plug valve has dual control of single outlet and double outlet. The product shall have a manufacturing license and a certificate from the fire department before use. The fire hydrant branch pipe shall be located at the coordinates and elevation of the plug valve, and shall be stabilized by fire hydrant box after verification. Plug valve should be installed after the box is aligned and stabilized. When the plug valve is installed in the box, it should be on the side of the door, and the door should be flexible to open.
Installation of water flow indicator: generally installed on the horizontal trunk of each floor or the trunk of a certain area. It should be installed horizontally, and the inclination should not be too large to ensure the sensitivity of the blades. Before and after the water flow indicator, there should be five straight pipe sections with installation diameters. When installing, pay attention to the direction of water flow consistent with the indicator arrow. Domestic products can be directly installed on the threaded tee, and imported products can be fastened with special-shaped clamps at the opening of the main pipe. The water flow indicator is suitable to be installed on the pipeline with a diameter of 50 ~150 mm.
Installation of fire pump: the specifications and models of the pump should meet the design requirements, the pump should be self-priming, the pump foundation should be constructed according to the design drawings, and the suction pipe should be equipped with shock absorbers. The booster pump need not be equipped with shock absorber, but the constant pressure pump should be equipped with shock absorber, the inlet and outlet should be fortified with noise facilities, and the outlet of the pump should be equipped with slow-closing check valve. The installation of the water pump pipeline shall be carried out after the water pump is positioned, leveled and stabilized. Water pump equipment shall not bear the pipeline quality. The installation sequence is the check valve, which is fastened on the water pump in turn. First, fix the pipe flange connected to the water pump to the valve flange, and then spot weld the pipe to the flange. Then, loosen the flange and weld it, cool it and connect it to the valve. Finally, another pipe section connected to the pipeline is welded. The flange of the pipeline shall be consistent with the flange of the pump and valve, and the handwheel of the valve installation shall be easy to operate, with consistent elevation and neat piping.
Installation of high-level water tank: it should be in place before the structure is capped, and full water test should be done. When the fire water is used with other water tanks, it shall be ensured that the fire water is not used by them, and the total fire water consumption is 10 minute. When used with domestic water, the water should always be in a flowing state to prevent the water quality from deteriorating. Check valve should be added to the fire outlet pipe (to prevent water from entering the water tank when the fire is pressurized). All water tank nozzles shall be prefabricated, and if the openings are welded on site, reinforcing plates shall be welded on the water tank.
Installation of water pump adapter: the specifications should be selected according to the design, including wall-mounted, ground-mounted and underground. Its installation position should be clearly marked, the valve position should be easy to operate, and there should be no obstacles near the coupler. The pressure of the safety valve should be kept constant according to the working pressure of the system to prevent the fire truck from damaging the indoor pipe network and components due to excessive pressurization, and the joint should be equipped with a drain valve. The pressure test of fire pipeline can be carried out in layers and sections. When supplying water, the highest point should be equipped with an exhaust device, and the high and low points should be equipped with pressure gauges. After filling with water, check the pipeline for leaks. If there is leakage in flanges, valves, etc., they should be fastened before pressurization, marked when leakage occurs after pressurization, and post-treated after pressure relief. Drain water if necessary. The ambient temperature of pressure test in winter shall not be lower than +5℃, and it is best not to use external water directly in summer to prevent condensation. After passing the pressure test, go through the acceptance formalities in time.
Pipeline flushing: After the pressure test is completed, the fire pipeline can be flushed continuously. Before flushing, remove the flow pressure relief orifice plate and filter device in the system, and reinstall them after the flushing water quality is qualified. The washing water should have a discharge destination and shall not damage other finished products. Nozzle branch pipe installation refers to a branch pipe at the end of the ceiling nozzle, which cannot be completed in turn with the main pipe at the same time, but should be carried out at the same time as the ceiling decoration. After the installation of ceiling keel, determine the elevation of nozzle reserved opening according to the thickness of ceiling material, and determine the coordinates of nozzle according to the installation of ceiling, so as to accurately locate the reserved opening of branch pipe. The branch pipe diameter is 25mm, and the end of the branch pipe is provided with 25mm× 15mm reducing hoop. The hoop mouth should be flush with the ceiling decoration layer, and the cable should be installed. The elbow at the end of the branch pipe should be fixed with a clip within the range of 100mm to prevent the nozzle from moving up and down in loose contact with the ceiling. After the branch pipe is installed, the reserved opening is tightened with a plug. Prepare the system for stress test.
Pressure test of spray system: pressure test of the system shall be conducted before the ceiling is closed. In order not to affect the progress of ceiling decoration, pressure test can be carried out in layers and sections. After the pressure test, the pipeline should be flushed, and the ceiling can be closed only after passing the test. Ceiling material, open a 30mm hole in the pipe hoop mouth to expose the reserved mouth. After the ceiling decoration, unplug the plug and install the nozzle.
Throttle device: In the high-rise fire protection system, the low-level sprinkler and fire hydrant flow is too large, so pressure-reducing orifice plate or throttle pipe can be used to balance it. The pressure relief orifice plate shall be set on the horizontal pipe section with a diameter of not less than 50mm, and the orifice diameter shall not be less than 50% of the diameter of the installation pipe section. The orifice plate should be installed on the straight pipe section on the downstream side of the water flow elbow, and the distance from the elbow should not be less than twice the diameter of the installed pipe section. When throttle pipe is used, its length should not be less than1m.
Installation of alarm valve fittings: it should be carried out before the project is completed. The delay device is installed on the automatic sprinkler system with closed nozzle, which is a facility to prevent false alarm. It can be installed according to the instruction manual and assembly drawing, and should be installed on the signal pipeline between the alarm valve and the hydraulic alarm bell. The hydraulic alarm bell is installed near the alarm valve. The pipeline connected with the alarm valve shall be galvanized steel pipe.
Installation of fire hydrant fittings: it should be carried out before the completion of the project. Fire hoses should be folded on hangers or tightly rolled in boxes. Fire hoses should be placed vertically in the box, and self-help hoses and hoses should be placed on elevators or at the bottom of the box. The connection between fire hose, water gun and quick connector is generally bound twice with 14# lead wire, with at least two turns each time. When using the clip, add a lead wire inside. When there is an electrical control button, attention should be paid to cooperate with the electrical specialty in construction.
Installation of sprinklers: The specifications, models and working temperatures of sprinklers should meet the design requirements. The protected area of nozzle installation, nozzle spacing and distance from wall and column should meet the specification requirements. The two wings of the sprinkler should be installed in rows. Mouth guards should be attached to the ceiling, and the wings of a single row of nozzles in the corridor should be installed horizontally. Special wrench (light fork type) should be used to install the nozzle, and ptef should be used as filler to prevent damage and pollution to the ceiling. Attention should be paid to the protected object in the installation of water curtain nozzles, and water curtain nozzles with the same caliber should be installed on the same water distribution branch pipe. The fixed bracket installation of spraying pipeline should meet the design requirements. The position of supports and hangers should be based on the principle of not interfering with the injection effect of nozzles. Generally, the hanger should be more than 300mm away from the nozzle, and the round steel hanger can be as small as 70 mm. In order to prevent the pipeline from shaking too much when the sprinkler sprays water, the main pipe and riser should be provided with anti-shaking fixed brackets. The main pipe or layered main pipe can be located in the middle of straight pipe section, and the distance from the riser and the end should not be greater than 12m. When the length of the single-pole hanger is less than 150mm, the anti-shake fixed bracket is not needed. The anti-sway fixing bracket shall be able to bear the total weight of water in pipelines, components, valves and pipelines and 50% of horizontal driving force without damage or permanent deformation. Risers shall be equipped with anti-swing fixing brackets in two directions. When the rain and water curtain automatic centralized fire extinguishing system is adopted, a manual opening device should be set. In general, dry automatic sprinkler system should be used in areas without heating facilities or areas with ambient temperature higher than 70℃. Before the nozzle of dry automatic sprinkler system is installed, pressure test and flushing should be done well. Conditional application of air compressor purging pipeline. The water supply commissioning of the fire fighting system should meet the requirements of the fire fighting department. The fire pump should be connected to the power supply and put into trial operation, and the pressure and flow of the nozzle and hydrant at the most unfavorable point can meet the design requirements.
After three years of study in water supply and drainage specialty, I have a comprehensive and in-depth understanding of water supply engineering, drainage engineering, water engineering construction, water pumps and pumping stations, and building water supply and drainage engineering. On this basis, the college arranged for us to practice in three places during the summer vacation from July/KLOC-0 to August 6: Xiamen Campus Construction Site, Huaqiao University Campus Water Supply Network Reconstruction, Quanzhou Quannan Water Supply Co., Ltd., during which our understanding of this major rose from rational to perceptual through on-site visits, listening to reports, reading construction drawings, consulting on-site leaders, engineers and technicians, and talking with students.
I. Overview of the Project:
Xiamen Campus is located in jimei district, Xiamen, next to Jimei Avenue, with convenient transportation. The campus has a total construction area of 800,000 square meters and a planned total investment of 2 billion yuan. Phase I (2006) construction land 1 160 mu, with a total area of 309,000 square meters and a total investment of 830 million yuan. The second phase (20 10) covers an area of 840 mu, with a total area of 304,000 square meters and a total investment of 8 10/00,000 yuan. The long-term construction area is 200,000 square meters. When we first came to Xiamen for internship, the progress of the project was roughly as follows: the comprehensive teaching building group project, the first phase of the student apartment project, the first phase of the student canteen project and the academic exchange center have all been completed, the internal facilities are being installed, and the first phase of the library project is being stepped up. The template of the computer room of reclaimed water treatment structure has just been removed, the template of sewage treatment poolNo. 1 is being removed, the concrete of sewage treatment pool No.2 is being maintained, and the drainage pipe network and fire fighting pipe network in the park are being tightened. Generally speaking, the overall construction project of Xiamen campus is a rush stage before completion.
The reconstruction of water supply network in Huaqiao University campus is the reconstruction of West China, in order to meet the needs of campus development. The whole project is mainly manual labor with a low degree of mechanization. Trenching, pipe laying and backfilling are all done manually.
Quanzhou Quannan Waterworks Co., Ltd. is a waterworks with a high degree of automation. We are here mainly to learn the management system and water treatment technology of waterworks.
2. Internship content:
1. Xiamen campus construction site:
Because Xiamen Campus is stepping up its construction and there are many kinds of projects, we can learn a lot about the engineering construction methods of this major. Because of the heavy workload, there are several construction teams in charge of the construction, and I can learn different construction methods for the same project, which is a great harvest of the internship. The harvest of site practice in Xiamen campus is as follows:
(3). Indoor and outdoor water supply and drainage pipeline construction:
(1). Indoor water supply and drainage pipeline construction:
A. Fire pipes
Indoor fire pipes are mainly equipped with fire hydrants and automatic sprinkler systems. Because of the different construction parties, I learned two ways to connect the fire-fighting pipes: one is the clamp connection, that is, after the nozzles of two fire-fighting galvanized steel pipes are aligned, rubber rings are put on them, and finally the bolts on both sides of the clamp are locked with clamps; One is threaded connection, that is, PTFE sealing tape is wound around the nozzle of two threaded fire-fighting galvanized steel pipes, then the internal thread is externally connected and finally tightened.
The installation of fire hydrant is a major point: the distance between the fire hydrant mouth and the ground 1. 1m, with an allowable deviation of 2mm；; The bolt mouth is outward and should be installed on the door shaft side; The center of the valve is 140mm from the side of the box and 100mm from the inner surface of the back of the box, with an allowable deviation of ±5mm；; The allowable deviation of verticality of fire hydrant box installation is 3 mm. Due to construction reasons, some places are not in place, such as the installation of fire hydrant box in the canteen, the bottom of the box is close to the ground, and the portable fire extinguisher is not in conformity with the requirements. (It is stipulated that the height of the top of portable fire extinguisher is not less than1.50m and the height of the bottom is not less than 0.15m). Fire-fighting riser is fixed with pipe clamp at the place 1.4~ 1.6m from the ground.
The sprinkler pipes of the automatic sprinkler system (from the International Convention Center) are all arranged under the beam 15~20cm. During my internship, the nozzle has not been installed, because I just finished the system pressure test at this time, and I can't install the nozzle until the flushing is qualified. (See July 19 Internship Diary for some sketches. )
(2). Outdoor water supply and drainage pipeline construction:
A. Fire pipes
The lower pipe of fire-fighting pipeline adopts lifting pipe and lower pipe, and the connection mode is clamp connection. Exterior wall of fire hose shall be painted with 1~2 anticorrosive asphalt. I was lucky enough to see the hydraulic test of buried pipeline of automatic sprinkler system during my internship. The specific method is as follows (see July 18 internship diary for a sketch):
Place bets on both ends of the pressure test pipe with plugs first, and then inject water into the pipe. When the water is full, it will overflow from the snorkel. At this point, close the inlet valve. When the pressure gauge shows 0.2~0.3Mpa, press it out from the water inlet pipe with a hydraulic pump. When the pressure reaches 65438±0.2 MPa, stop pressurizing and close the inlet valve. After half an hour, if the pressure value displayed on the pressure gauge is greater than 1. 15Mpa, it is considered qualified, or if the pressure value is between 0.4 and 0.5mpa after 24 hours of pressure test, it can also be considered qualified. (This test method and the specified system test pressure are 1.5 times the working pressure, but not less than 0.6Mpa. Under the test pressure, the pressure drop is not more than 0.05Mpa within 10min, and then the working pressure is checked, and the pressure remains unchanged, which basically conforms to the principle of no leakage).
Three. internship summary
Soon, the four-week internship time passed. During the four-week internship, I learned a lot of knowledge that is impossible to learn in textbooks. The internship situation is summarized as follows:
Through practice, I know the focus of my study, increase my perceptual knowledge of my major and improve my ability to solve practical problems. Through practice, I have improved my ability to read drawings, and my understanding of construction drawings can be said to be a leap from ignorance to understanding. Through practice, strengthen the ability of integrating theory with practice and make up for the shortcomings in the classroom; Through practice, I laid a solid foundation for the study of subsequent professional courses, and also laid a certain foundation for my social work after graduation; Through practice, I have cultivated my hard-working spirit and learned how to communicate with on-site construction personnel and technicians.
The content of our internship is quite rich, which enhances my engineering consciousness and innovation consciousness, broadens my horizons and gives me unprecedented exercise.