Agenda - Public Works Committee - 05/18/2010

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Richard G. Kraft 1) PE3408/PE3608 - this is for the older materials and reflects the change in designation only. For large diameter water mains made to ASTM D3035 consider the difference in product made from the two materials: 2) PE3408/PE4710 -this indicates the producer is using the new bi-modal resins and the pipe or tubing has significantly higher pressure capacity than PE3408 product. Dual marking allows pipe to be used when the utility specification does not incorporate the new material designation codes or the new bi- modal resin code. Dual marking will eventually be eliminated and that will mean some utilities will no longer be able to purchase PE-3408 pipe that their standards call for. The end game is not the PE-3408 / PE- 3608 transition. It is the introduction and standardization of the PE-4710 piping materials. Market forces are also likely to drive pipe producers to drop PE-3408/PE-3608 altogether. As utilities recognize the advantages of using bi- modal resin and as usage of older resins decline it is likely resin producers will drop the older uni- modal resins totally. ZS years ago PE-3406 resin was in use throughout the industry. About 5 years after the introduction of PE-3408, PE3406 resin was dropped completely. Consider the implications of using 1" SDR 9 PE3408/PE3608 vs. using tubing produced from the new PE4710 material: 1" CTS SDR 9 1" CTS SDR 9 PE3408 PE34o8 TUBING TUBING Pressure Rating 200 PSI 250 PSI Tensile Strength 1301 PSI 1463 PSI Life Expectancy 50 Years 100 Years 8" 8" PE3408/PE3608- PE4710 -SDR SDR 11 Pipe 13.5 Pipe Pressure Rating 160 PSI 160 PSI Weight Per Fooc 8.45 Lbs./foot 7.03 Lbs./foot Inside Diameter 7.057" 7.347" In this scenario the pipe produced from PE 4710 is 16% lighter and has a 4% greater internal diameter. The benefit to the end user is an easier to handle product, less expensive and higher flow capacity. Overall the PE-4710 products have a 25% increase in pressure rating for comparable SDR's and in many cases the opportunity exists to select a higher SDR for a lighter weight pipe with a higher flow capacity. When specifying pipe it is important to site the cell classification of the product you want. The cell classification outlines the minimum level of perforrance the HDPE material must have to perform satisfactorily in your system. One way to ensure that you always obtain the correct product is to adopt a detailed specification. Standards have been as simple as the materials designation such as PE3408 or PE4710 and nothing more. At this level of specification, the product you purchase may or may not be the best for your system and may not offer the highest level of performance and longevity. If you examine the cell class of various PE-4710 materials, you will find that not all PE-4710 resins are the same and some have much lower levels of perfortnuice than others. Endot offers a model specification that can be a starting point toward developing a standard for your utility. Your standard can be as simple as the material designation or can include cell class, coil size and length, color, and other features that are needed or desired in your system. Journal NEWWA June 2008 139 ~0