Design pressure and working pressure of the PB pipe.

- Jul 25, 2018 -

Preparation before construction


1. The construction personnel must be familiar with the plan and design description of the project and related specifications and regulations.


2. The construction personnel must hold the plumbing work permit and work through the technical training of the construction water supply polypropylene pipe installation.


3. The used equipment and related equipment must have good performance to ensure normal construction.


4. The construction site should be level and clean. No other debris such as sand and gravel is allowed, and there is no obvious deviation of the elevation.


5. Temporary facilities such as construction electricity, water, material storage and release, can meet the construction needs.


When the ambient temperature is below 10 °C, the construction should be stopped or the winter construction plan should be adopted.


1. Indoor pipe laying


(1) When installing the dark-coated pipeline, it is advisable to cooperate with the civil construction to reserve the groove. The surface of the groove must be flat, and there should be no sharp objects such as sharp corners, slag, ash, etc. When the dimension design is not specified, the depth of the groove is De+40mm. The width is 300mm. The pipes in the concaves should be positioned strictly according to the drawings, and should be laid along the wall to avoid damage to the pipes during the second renovation.


(2) When the pipe clamps in the groove are installed, the spacing is 1000mm, and the double pipe clamps should be on the same axis.


(3) The hot water (heating) pipe buried directly in the groove, because the cement mortar limits the thermal expansion of the pipe, so the longitudinal expansion compensation can be ignored. When the radiator is installed, when the riser is less than or equal to 1 meter, install a fixed card, which is 600mm from the ground. The length of the horizontal pipe (water supply) of the radiator is not less than 200mm. Note: (The horizontal water supply pipe has a slope of 0.5cm).


(4) The laying of pipes below the indoor floor (±0.00) shall be re-excavated after the backfilling of the civil works is completed. The bottom of the laying pipe should be flat and there should be no protruding sharp objects. The particle diameter of the soil should not be greater than 12mm, and if necessary, a 100mm thick sand cushion can be laid.


(5) When the first layer of buried pipeline is backfilled, the backfill of the pipe shall not be in contact with the pipe wall directly. The sand or soil with a particle diameter of not more than 12 mm shall be backfilled to the upper part of the pipe at 300 mm, and the indoor buried pipe shall be buried. The buried depth of the pipe top should be no less than 300mm.


(6) Installation of surface-mounted pipes shall be carried out after the completion of the civil works. Before installation, the holes shall be reserved with the existing holes or pre-embedded casings. Do not twist axially during installation. Forced correction is strictly prohibited when passing through walls or through floor slabs. When the PP-R pipe is laid in parallel with the metal pipe, it should have a certain protective distance. The net distance should be no less than 100mm. The PP-R pipe should be inside the metal pipe.


(7) Steel pipes shall be provided when the pipes pass through the floor. The casings shall be larger than 50mm above the ground and have good waterproof measures.


(8) When the hot water pipe is worn through the wall, a steel casing shall be provided, and the burr shall be removed in the steel casing. When the cold water pipe passes through the wall, a hole can be reserved, and the size of the hole is 50 mm larger than the outer diameter. PVC sleeves should be used when wearing simple walls to prevent damage to the tube surface.


(9) When the pipeline is worn through the foundation wall, steel casing shall be provided. The clearance above the reserved hole of the casing and the foundation wall shall be no less than 100mm if the design is not specified.


(10) When the support and hangers laid by the open pipe are compensated for the expansion of the pipeline, the construction shall be carried out according to the requirements of the fixed point. Reliable fixing measures shall be adopted at each water distribution point, force point and wall branch pipe joint of the pipeline.


(11) When the pipeline is used for the water supply pipe of the feed water pump, technical measures to eliminate the water hammer should be taken.


2, outdoor pipeline laying


When laying outdoor direct buried pipelines, the bottom of the tank should be flat, a 100mm thick sand cushion should be laid around the pipeline, and then the soil should be backfilled. When crossing the road, the distance between the top of the pipe and the road shall not be less than 800mm. The buried depth of the pipe at the sidewalk and other places shall not be less than 600mm to ensure the anti-freezing layer and construction quality. If it is not required, steel casing and other protection must be added. Measures.


3. For the installed pipeline, the pressure test and the acceptance record of the concealed project should be done before closing.


Winter construction requirements


1. In addition to the general requirements, the indoor construction should also comply with the winter construction requirements. For example, the pipe should be transported from the material storage site to the construction site, and the ambient temperature around the welding site should be heated by heating equipment such as a small sun or a hot air blower. Construction above 10 °C is allowed, and it is strictly forbidden to bake with open flame.


2. In addition to the general requirements, the outdoor construction should also comply with the winter construction requirements, such as: transporting the pipe from the material storage site to the construction site, placing the weld in a simple shelter with a closed wind, using a small sun, heat Heating equipment such as fans will raise the ambient temperature outside the welded joint to above 10 °C, and then weld, and it is strictly prohibited to use open flame baking.


Construction quality requirements


1. In addition to the design basis of the project, the construction and installation should also comply with the “Code for Construction and Acceptance of Heating and Sanitary Engineering” (GB/J242-82) and related regulations and regulations.


2. When the pipeline passes through the dark beam, the center of the hall, and the doorway, avoid cross-laying with the electrical pipe.


3. The specifications, model and pressure rating of the installation pipe and fittings shall comply with the design and acceptance specifications.


4. When the ambient temperature is below 10 °C, the pipe is subject to the chemical properties of the material itself, and it is easily broken in case of external force. Therefore, in the winter construction, it must be handled carefully, and the pipe should not be thrown, thrown, rolled, dragged or smashed. Appropriate external force.


5. When the ambient temperature is lower than 10 °C, the construction will continue, which will seriously affect the construction quality. Therefore, it is necessary to carry out the construction according to the winter construction requirements.


6. The installed pipelines should not be stressed or tapped. If necessary, cover the parts that are vulnerable to external forces, especially the water supply pipes of pipeline wells without floor closures. It is necessary to take protective measures to avoid bumps and heavy objects. (Bricks) and the like cause impact on the PP-R.


7. When the construction environment temperature is less than 10 °C and close to 5 °C, the heating time of the hot-melt pipeline should be extended by 50%, and the adjustment time should be shortened.


8. After passing the water pressure test in the groove, fill the cement with a cement mortar of not less than C20 grade and add the condensing agent. Otherwise, due to the thermal expansion and contraction of the pipeline, the ground will be cracked. Especially hot water (heating) pipes.


9. Pipes for hot water (heating) should be pipe fittings of not less than 2.0Mpa.


10. During the installation of the pipeline system, the opening should be blocked in time.


11. It is strictly forbidden to heat-melt different grades of PP-R pipes and fittings.


12. Pipes that are darkly laid under the floor surface or inside the wall shall not be connected by wire or flange.


13. The PP-R pipe shall not be directly connected to the water heater or the hot water unit, and the metal pipe section with a length of not less than 400 mm shall be used for the transition.


14. Personnel entering the construction site should wear soft-soled shoes. During the construction process, the workers should carefully handle the tools and properly preserve the tools to avoid damage to the pipes.


Hydraulic test, flushing, disinfection and acceptance of pipes


1. Hydraulic test


(1) The test pressure of the cold water pipe shall be 1.5 times of the working pressure of the system, but shall not be less than 0.9pa.


(2) The test pressure of the hot water pipe shall be 2.0 times of the working pressure of the system, but shall not be less than 1.2Mpa.


(3) Pipes buried directly in the surface of the floor and in the wall. The hydraulic test must be carried out before pouring or plugging, and the construction can be continued after the test pressure is passed.


(4) Pipes for hot-melt connection, the hydraulic test shall be carried out 24 hours after the pipe connection.


(5) The hydrostatic test shall comply with the following requirements:


1 The water pressure test should be carried out in stages, and the total length of the test pipe section should not exceed 500 m;


2 Before the test, the pipeline should be fixed, the joints should be exposed, and the water distribution equipment should not be connected;


3 pressure gauge is installed at the lowest point of the test pipe section, the pressure accuracy is 0.01MPa;


4 Slowly fill the pipe with water from the lowest point of the pipe section, fully exclude the air in the pipe, and check the watertightness.


5 pairs of pipelines are gradually boosted, and the boosting should use a manual pump, and the boosting time is not less than 10 min;


6 After boosting to the specified test pressure, the voltage is regulated for 1 h, and the pressure drop must not exceed 0.06 MPa;


7 in the state of 1.15 times the working pressure, the voltage is regulated for 2h, the pressure drop shall not exceed 0.03MPa;


8 during the test. No leakage at each joint is qualified;


Note: Allow two pressures in 30 minutes and raise to the specified test pressure.


(6) After passing the water pressure test, connect the pipe end to the water distribution part, supply water with the design pressure of the pipe network, and open the water distribution parts at the same time in batches. The water at each water distribution point should be unblocked.


2. Cleaning and disinfection of pipelines


(1) After the water supply pipe system has passed the test pressure, it should be cleaned by water before completion acceptance. When flushing, open the water nozzle of each water distribution point, and the lowest point of the dead angle system should be provided with a water outlet. The cleaning time is controlled until the water quality of the water outlet is equal to the water quality of the system. The water flow speed during flushing should not be less than 1.0m/ s.


(2) After the pipeline system is cleaned, use the clean water containing 20-30mg/L free chlorine to fill the pipeline for disinfection. The chlorine-containing water should be allowed to stand in the tube for more than 24h.


(3) After the pipeline is cleaned, it can be washed out with drinking water and passed the inspection by the health supervision and management department before it can be delivered.


3, quality acceptance


Intermediate acceptance


For the installation of concealed pipes and surface-mounted pipes, the hydraulic pressure test shall be carried out by the construction unit in conjunction with the supervision unit.


(1) The cold and hot water pipes shall not be confused;


(2) Installation position and firmness of pipe supports and hangers;


(3) Opening and closing flexibility and fixed firmness of valves and water distribution parts;


(4) The cleanliness, firmness and tightness of the connection interface;


(5) The smoothness of the water at the water distribution point, the vibration and noise at the time of closing;


(6) Selection, thickness and practice of insulation materials;


(7) Rationality of compensation measures for pipe expansion and contraction


(8) Correctness of elevation and slope.


Total experience


Total experience and acceptance conditions:


(1) Construction drawings, as-built drawings and design change documents.


(2) On-site acceptance records of pipes, fittings and quality assurance materials.


(3) Concealed project acceptance records and intermediate experimental records.


(4) Pressure test and ventilation ability test record.


(5) Records of gas purge and disinfection of drinking water pipelines, and reports of pipeline ventilation disinfection issued by the health and epidemic prevention department.


(6) Record of project quality accident handling.


(7) Engineering quality inspection and assessment records.


Finished product storage protection requirements


1. The completed PP-R pipeline is strictly prohibited from impacting on the pipe or nailing metal nails and knocking, heavy objects, and smashing.


2. In winter, in order to prevent freezing of PP-R pipes, it is strictly forbidden to store water during non-use.


3. When handling pipes and fittings in winter, care should be taken to avoid oil stains, no impact, collision with sharp objects, throwing, falling, rolling, dragging, etc., to avoid damage to pipes and fittings, affecting the service life and construction quality of pipe fittings.


4. Pipes and fittings should be placed in warehouses or simple sheds. They should not be stored in the open air to prevent direct sunlight. Pay attention to open flames. The distance should be no less than 1 meter.


5, the pipe should be stacked horizontally on the flat ground, avoid bending the pipe, the stacking height should not exceed 1.5 meters, the pipe fittings should be piled up layer by layer, and should not be piled too high.

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