Technical requirements for water-saving irrigation

Technical requirements for water-saving irrigation

1、 General

1. The project construction shall comply with the following procedures and requirements: ① foundation pit drainage: open ditch drainage or well point drainage system shall be set to drain the accumulated water in the foundation pit. ② Foundation treatment: when the bearing capacity of foundation pit foundation is less than the design requirements, foundation treatment must be carried out. ③ The masonry of irrigation valve well shall comply with the current Code for Construction and Acceptance of Masonry Engineering, Code for Construction and Acceptance of Reinforced Concrete Engineering, and Code for Construction and Acceptance of Underground Waterproof Engineering. ④ Backfilling: after the masonry is completed, backfill shall be carried out after the masonry mortar or concrete has solidified to the design strength; Backfill soil shall be dry and wet, compacted layer by layer, and tightly contacted with masonry.

2. During construction, construction records shall be made. For concealed works; The Hidden Works Record must be filled in; The next process can only be started after passing the acceptance; The next process can only be started after the completion of all works.

3. Pipe network construction (1) The trench and pipe trench excavation shall meet the following requirements: ① The excavation shall be carried out according to the construction setting-out center line and the marked design elevation of the trench bottom, and shall not be excavated below the design elevation of the trench bottom. In case of local overbreak, the same soil shall be filled and compacted to close to natural compactness. The bottom width of the trench shall be determined according to the diameter, material and construction conditions of the pipeline. ② Where the trench passes through rocks, pebbles and other places that are easy to damage the pipeline, the trench bottom shall be excavated at least 15 cm more and backfilled with sand or fine soil to the design elevation. ③ The pipe joint groove shall meet the design requirements. (2) The backfill of pipe trench shall meet the following requirements: ① After the installation of pipes and fittings; The soil shall be filled and positioned, and backfilled as soon as possible after passing the pressure test. ② Before backfilling, all sundries in the trench shall be removed and the accumulated water shall be drained. ③ Backfilling must be carried out on both sides of the pipeline at the same time. It is strictly forbidden to backfill on one side. The backfill should be compacted in layers. ④ UPVC pipes shall be backfilled when the ground and underground temperatures are close; The backfill around the pipe shall not contain stones with a diameter greater than 2.5 cm and soil blocks with a diameter greater than 5 cm. The pipe shall also be filled with water when the semi-soft plastic pipe is backfilled. The backfill can be filled with water.

2、 Equipment installation

1. The installation of irrigation system equipment shall meet the following conditions: ⑴ The installation personnel have understood the equipment performance and installation requirements. ⑵ The tools and materials for installation have been prepared, and the machines and tools for installation have been checked to be safe and reliable. (3) The civil works related to equipment installation have been accepted. (4) The equipment to be installed has been checked according to the design and passed the inspection. The inside of the equipment is clean and free of sundries.

2. The equipment shall be inspected according to the following requirements: ⑴ The equipment, specification, material, model and connection size shall be checked according to the design requirements, and the appearance quality shall be checked. ⑵ The sampling inspection shall be carried out for pipes and fittings. The quantity of sampling inspection shall not be less than 3 pieces. If the sampling inspection is unqualified, double the number of unqualified items shall be retested. If one of the retest results is still unqualified, the whole batch is unqualified. (3) The instruments, meters and measuring tools used for inspection shall have the inspection certificate issued by the metrological department. (4) Inspection records shall be filed.

3. The installation of buried pipes shall comply with the following requirements: ⑴ The pipes shall not be installed with wooden mats, brick mats or other mats, and shall not be installed on frozen soil foundation. ⑵ The pipeline should be installed from low to high, in the order of main pipe first and branch pipe later. (3) The pipeline shall not collide with the trench wall or bottom during lifting. (4) During pipe installation, the water in the trench shall be drained and the pipe bottom shall be in close contact with the pipe base. (5) When brittle pipes and UPVC pipes cross roads or railways, they shall be protected by casings or culverts.

4. When installing valves and pipe fittings with flanges, the flanges shall be coaxial and parallel to ensure the free penetration of bolts. It is not allowed to eliminate skew by tightening bolts.

5. When the pipeline installation is carried out by stages or interrupted for some reason, the opening shall be closed with plugs.

6. During equipment installation, quality inspection shall be carried out at any time, and correct and sundries shall not be left in the equipment.

7. The bonding and connection of UPVC pipes shall meet the following requirements: ⑴ Before bonding: ① Select the appropriate adhesive according to the design requirements. ② According to the bonding technical requirements, the pipe or pipe fittings shall be pre-processed and pretreated. ③ According to the requirements of bonding process, check the fit clearance, and clean and roughen the joint. (2) Bonding ① The pipe axis should be aligned and the fit clearance around should be equal. ② The application length of adhesive shall be fixed according to the design. ③ The adhesive shall be applied evenly, and the gap shall be filled with adhesive, with a small amount of extrusion. (3) After station connection: ① The pipeline shall not be displaced before curing. ② Quality inspection shall be carried out before use.

8. The flanging connection of UPVC pipes shall meet the following requirements: ⑴ Before flanging: ① Before flanging, the pipe ends shall be sawed, filed, cleaned and dried. ② The flanging shall be perpendicular to the center line of the pipe, and the size shall meet the design requirements. ③ The front and back sides of the flanging shall be flat and can ensure the free loading and unloading of flanges, bolts or quick connectors. ④ The connection between the flanging root and the pipe shall be well fused without slag inclusion, perforation and other defects; The flash and burr shall be removed. (2) The connecting ① sealing ring shall be concentric with the pipe. ② When tightening the flange bolts, the torque shall meet the standard, and the stress of each bolt shall be uniform. (3) After connection: ① The flange shall be put into the joint pit. ② The center line of the pipe shall be straight, and the bottom of the pipe shall fit well with the bottom of the groove.

9. UPVC pipe sleeve connection shall meet the following requirements: ⑴ Before connection: ① The fit clearance shall meet the design and installation requirements. ② The sealing ring shall be installed into the sealing groove of the sleeve without distortion and deflection. (2) Connection: ① The depth of the pipe inserted into the sleeve shall meet the design requirements. ② When it is difficult to install, soapy water or talcum powder can be used as lubricant; It can be installed with a thread tightener, or it can be tapped in with a wooden block. ③ After connection: the sealing ring shall not be displaced, twisted or skewed.

10. The hot-melt butt joint of plastic pipe shall meet the following requirements: ⑴ Before butt joint: ① The material, diameter and wall thickness of the hot-melt butt joint pipe shall be the same. ② The pipe shall be pre-processed according to the requirements of hot melt butt joint, and the impurities and dirt at the pipe end shall be removed. ③ The pipe end shall be heated to full without burning according to the design temperature; The heating plate shall be clean, flat and smooth. (2) Docking: ① The heating plate shall be pulled out and the two pipes shall be closed quickly, and the end faces of the two pipes shall be completely aligned; The resin shall be extruded evenly around. ② Keep clean when cooling. Natural cooling shall prevent dust intrusion; The water quality shall be kept clean during water cooling. (3) After butt joint: ① The two pipe ends shall be welded firmly, and the spot check shall be conducted according to 10%. ② If the butt joints at both ends are not aligned, cut and rework the butt joints. ③ The pipe shall not be displaced before complete cooling.

11. Branch pipe and riser installation ⑴ The connection between branch pipe and riser shall be sealed and reliable. ⑵ The vertical pipe shall be installed vertically and stably.

3、 Pipeline hydrostatic test

（1） General provisions

1. During construction and installation, the pipeline shall be subject to sectional water pressure test. After construction and installation, the pipe network water pressure test shall be carried out. After the test, a water pressure report shall be prepared. For smaller projects, sectional hydraulic test may not be conducted.

2. Grade 0.35 or 0.4 standard pressure gauge shall be selected for hydraulic test. The measured pipe network shall be equipped with pressure regulating device.

3. The following preparations shall be made before the hydrostatic test: ⑴ Check the equipment condition of the whole pipe network; The opening and closing of the valve shall be flexible, and the opening shall meet the requirements; The exhaust and air inlet devices shall be smooth. (2) Check the filling and positioning of buried pipes. The pipes shall be fixed, and the joints shall be exposed and the water seepage can be observed clearly. (3) Water flushing pipeline and accessories: flush continuously according to the design flow of the pipeline until the color of the water at the outlet is consistent with the transparency and the visual inspection at the inlet.

（2） Water pressure resistance test

1. The pipeline test length should not be greater than 1000 meters.

2. After the pipe is filled with water, the metal pipe and UPVC pipe can undergo the water pressure test after 24 hours.

3. The test should be carried out at the ambient temperature above 5 ℃, otherwise there should be thawing measures.

4. The test pressure shall not be less than 1.25 times of the system design pressure.

5. The pressure shall be increased slowly during the test. After reaching the test pressure, the pressure shall be maintained for 10 minutes, and it is qualified if there is no leakage or deformation.

4、 Project acceptance

1. Acceptance standard for irrigation works (1) After the expiration of the defect liability period, the irrigation system operates normally without running, emitting, dripping and leaking. (2) Plants grow normally without uneven drought and flood. (3) The pipeline shall be free of loss, damage and blockage. (4) The surface soil buried in the whole system has no settlement and subsidence.

2. The concealed works of the irrigation system must be inspected and accepted during the construction period, and the next process can only be carried out after passing the inspection. (1) Check whether the foundation size and elevation of the pipe network, the position and depth of embedded iron parts and anchor bolts, the position and size of holes, holes, ditches, settlement joints and expansion joints meet the design requirements; Whether the trench depth, bottom width, slope direction, foundation treatment, construction and installation quality of the buried pipeline meet the design requirements and the provisions of this specification. Water pressure test shall be conducted for the pipeline. (2) After the concealed works pass the inspection, there shall be a certificate and acceptance report.

3. The completion acceptance (1) shall review whether the technical documents are complete and correct. (2) Check whether the civil works meet the design requirements and the provisions of this specification. (3) It is necessary to check whether the equipment selection is reasonable and whether the installation quality meets the requirements of this specification, and start the electromechanical equipment. (4) The test run of the whole system should be carried out, and various technologies should be measured. (5) After completion acceptance, the completion acceptance report shall be prepared.