Pipe main control parameters and basic requirements

The main control parameters and basic requirements of the pipe 1. The main control parameters The PP-R PP pipe system for hot and cold water uses the main control parameters as the pipe series related to its design pressure. The nominal pipe outside the PP pipe is required. Basic physical parameters such as diameter, nominal wall thickness, and longitudinal retraction rate.

2. Mainly applicable to indoor hot and cold water pipes, heating and air conditioning pipes, and drinking water pipes.

3. Basic requirements 1) The production of PP-R pipe and pipe for hot and cold water shall meet the requirements of GB/T 18742.1-2002 for the main specifications and performance and performance requirements. 2) Sanitary requirements The chlorinated polyvinyl chloride piping system for drinking water should meet the requirements of GB/T 17219-1998.

4, the general product selection process for hot water pipe based on its design temperature and useful life to determine its application level, and then determine its S value according to its design pressure, and then determine the wall thickness according to its diameter; for cold water pipe, directly according to its The design pressure determines its S value, then determines its wall thickness according to its pipe diameter, and combines the technical conditions such as system layout, laying method, connection form, and compensation for temperature changes, and selects products whose quality meets the standards. The specific selection method of PP pipe can refer to 02SS405-2 "Random Copolymer Polypropylene (PP-R) Water Supply Pipe Installation".

5. Construction and installation points 1) The bottom of the buried pipeline should be smooth and there must be no protruding hard objects. The original soil particle size should not be greater than 12mm, if necessary, can be 100mm thick sand cushion. The backfill surrounding the pipeline should be filled 300mm above the top of the pipe. After compaction, the original soil can be backfilled. The buried depth of the underground pipeline should not be less than 300mm.

2) Each PP-R pipe manufacturer has specific requirements for the design, use, and installation of its products. The engineering practice shows that the following points must be especially noted: The thermal expansion of pipelines should be fully considered, and the necessary conditions should be taken Measures. Practice shows that there are usually several ways to solve the PP pipe problem:

(1) Small-diameter pipes should be directly concealed as far as possible.

(2) Freely compensating as far as space is allowed in the surface of the open and non-buried (tube wells, pipe trenches, etc.) concealed pipelines.

(3) Use semi-circular metal pallets to reinforce the pipeline.

(4) Constrained pipe deformation is fixed by dense pipe clamps. This method can be adopted under the conditions that all three methods mentioned above are subject to conditions that cannot be implemented.

(5) The above four methods are used together, and appropriate combinations are taken according to the actual situation.

(6) Metal compensators are used. Unless it is very important and convenient to repair, this method is generally not recommended. Because the mechanical connection between the metal compensator and the PP-R pipe is non-permanent, leakage points are easily generated. In addition, the price of the metal compensator is relatively expensive and the compensation amount is small, which is not suitable for the thermal expansion compensation of the plastic water supply pipe. .

(7) Strictly follow the welding operation regulations and other safety construction regulations. Due to the different temperatures, different diameter PP-R pipe welding depth, heating time, plug-in time have strict requirements, and in the heating and plugging process is not allowed to turn the pipe and pipe fittings, otherwise it is prone to weld quality problem. There shall be no open fire at the operation site of the pipeline, and it is forbidden to bake the PP pipeline.

3) For details of construction practices, please refer to the National Building Standard Design Atlas 02SS405-2 "Radiator Polypropylene (PP-R) Water Supply Pipe Installation".