The European industrial system plastic pipe application design system is based on DVS (German Welding Association) 2210-11. The long-term performance of thermoplastic pipes is extrapolated according to ISO90802. And the design basis is 50 years of service life.
For example design is defined as American Standard HDPE4710, ASTM D3350 CL445574C, ASTM F714 IPS DR9. Among them, PE4710 and ASTM D3350 both refer to material properties. The four digits in PE4710 point to the 1, 5, and 6 three-digit codes of the CL classification mark. And ASTM F714 is the specification standard of American Standard PE pipe. The difference between ISO PE100 and American Stand PE4710, mainly reflected in the following aspects:
1. Raw Materials
The PE100 used for ISO pipes will be produced from Borealis Borstar® HE3490LS or similar Eltex® TUB121 raw materials. They all have been listed as PE4710 materials by PPI 3(Plastic Piping Institute of the United States). The remaining three digit codes in the CL classification standard, namely the three digits 2, 3, and 4 in "CL4XX455XX74C". They are respectively represent Melt Index <0.15, elastic modulus 552-758Mpa and yield Tensile strength 21-24Mpa. Because European material suppliers and American material suppliers use different standards for testing, it is impossible to directly compare the results of these three indicators. The last letter code C represents carbon content> 2%, which HE3490 can meet.
The recommended ISO pipe is D710/SDR11. The nominal pressure rating is PN16, and the specific specifications of the original American standard pipe are compared with the following table.
|ISO SDR11||American Standard DR9|
|DN||Outer Diameter||Wall Thickness||Inside Diameter||Inch||Outer Diameter||Wall Thickness||Inside Diameter|
The inner diameter of ISO pipes has been reduced by 2%. The nominal pressure rating of American standard DR9 pipes is PN17.2, while the nominal pressure rating of ISO pipes is PN16. It should be pointed out that in the two size standards of the American Standard, no matter ASTM D3035 (maximum 24") or ASTM F714, 30"DR9 are beyond the standard range.
Temperature Reduction: In the American standard system, after various methods of calculating temperature reduction are introduced in the PPI manual, only the recognized temperature reduction coefficient below 100°F (38°C) is given. For those higher than 100°F, it is still recommended that the manufacturer Give yourself the available pressure levels at different temperatures. In the ISO system, the temperature-pressure curve is generally based on the method of ISO9080 extrapolation.
3. Pipe Fittings
Due to cost and process reasons, large-size pipe fittings are usually not produced by injection molding. American standard pipe fittings are welded in sections (shrimp bends), and pipe fittings are assembled from pipelines. In addition to segment welding, ISO pipes also provide hot-bending forming pipe fittings.
Regarding the pressure rating of the processed pipe fittings, a 25% reduction is usually adopted in the PPI specification. But at the same time, it is recommended that each manufacturer mark the pressure rating by itself. For ISO hot-bent formed pipe fittings, the manufacturer can guarantee the same pressure level as the pipeline (sample mark and pressure test report can be provided).
In summary, the following table shows the comparison of pressure levels under different temperature conditions between the American standard and the ISO system. The American standard system is listed according to the parameters of each manufacturer's sample.
4. Connection Method
It is recommended to use electrofusion welding. The electrofusion welding connection specification comes from DVS5, and the covering standard is DIN80746, of which the size range is 1600.
PE100 Pipe is used successfully in Europe for pressure pipe applications for more than 20 years. It has good performance by its features. PE4710 is derived from PE100. It is higher pressure capability, resistance to slow crack growth (SCG) & resistance to rapid crack propagation (RCP). Current North American standards methodology as it related to stress rating of modern HDPE pipe material capability was overly conservative.
- PE100 materials have similar or lower physical property requirements than PE4710 materials.
- The Design Factor of PE4710 is more conservative than that of PE100.
- There are additional higher performance requirements of PE4710 materials than PE100 materials, so not all PE100 materials will qualify as a PE4710 material.
1.DVS2210-1_1997 Industrierohrleitungen aus thermalplastischen Kunststoffen Projektierung und Ausfuehrung Oberirdische Rohrsystem.
2. ISO 9080_2003 Plastics piping and ducting systems -Determination of the long-term hydrostatic strength of thermoplastics materials in pipe form by extrapolation
3. Page 38, Table I.A.13-2, PPI tr-4_hdb_hds_sdb_pdb_mrs_listed
4. Material Datasheet, Borstar HE3490 LS.