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How to both safety and economic selection pp-r pipe fitting

2012-5-21      View:

A, how to both safety and economic selection pp-r pipe fitting?

1, correct identification of PPR pipe fitting quality: real pp-r pipe fitting should comply with the standard ISO/DIS 1999-15874.2 < < hot and cold water in plastic pipe system, the second part PP pipe > > pipe should comply with the standard ISO/DIS 1999-15874.2 < < hot and cold water in plastic piping systems - third part PP pipe fittings > >; The performance of the pseudo pp-r pipes and pipe fittings is through the above standards. It should be pointed out that the service life of pseudo pp-r pipe fitting is only 1-5 years, the real service life of pp-r pipe fitting are in more than 50 years.

2, pay attention to the overall use of pp-r pipe fitting coefficient C (safety coefficient) to determine:

General situation, and long-term continuous make temperature < 70 ℃, can choose C = 1.25; On important occasions, and long-term continuous working temperature of 70 ℃ or higher, and may have a run at a higher temperature for a long time, can choose C = 1.5;

3, used for cold water (40 ℃) or less system, choose P.N 1.0 ~ 1.6 MPa pipes, pipe fittings;

Used for hot water system use acuity PN2.0 MPa pipes, pipe fittings.

After considering the three principles, fitting to the SDR should be no greater than pipe SDR, namely the pipe wall thickness shall be not less than the same specification pipe wall thickness.

Second, pp-r pipe fitting problems which should be paid attention to in installation?

1, pp-r pipe fitting the tube is low hardness, poor rigidity, should be protected in the transportation, construction, to avoid inappropriate external force caused by mechanical damage. After dark apply to mark the pipe position, decorate in order to avoid the secondary damage the pipe.

2, pp-r pipe fitting there is below 5 ℃ low temperature brittleness, winter construction should be careful and sharp tools should be used when cutting tube slow cutting. Can't installed the pipe pressure, stroke, when necessary to protect vulnerable to external parts cover.

3, pp-r pipe fitting, long-term exposure to ultraviolet radiation aging degradation, installed in the outdoor or direct sunlight place must bind up dark protective layer.

4, pp-r pipe fitting with metal or water with a screw thread insert for the connection or flange mechanical connection way, the rest shall be connected by hot melt, unifying the pipes, no leakage point.

5, the linear expansion coefficient of pp-r pipe fitting is bigger (0.15 mm/m ℃), the surface mounted or straight compress undercut tube when the expansion deformation of technical measures must be taken to prevent pipes.

6, after the pipe installation in the sealing tube (buried) and cover the adornment layer must be test before (not straight successfully apply). Cold water pipe pressure test pressure for the system working pressure of 1.5 times, but shall not be less than 10 mpa; Hot water pipe test pressure for 2 times the working pressure, but shall not be less than 1.5 MPa. Pressure testing time and method of technical requirements.

7, pp-r pipe Ming fu or straight compress tube, undercut, the hanger must be installed in accordance with the provisions.