|
Frequently Asked Questions
How long has HDPE been used in sewer and water applications? Polyethylene has been used around the world for sewer force mains, gravity flow sewers, and pressure water main applications for approximately 50 years. After many years of field proven performance, it became a standardized material and product. Is polyethylene pipe affected by chemicals?Plastics are not subject to galvanic corrosion, as are metals, since they are not conductors. However, plastics can be affected through direct chemical attack, strain corrosion, or solvation. The extent of the resistance is a function of many items, including time, temperature, and stress of contact. For more information you can contact Asset International Ltd. Will sunlight adversely affect HDPE pipe?If the proper amount of ultraviolet stabilizer has been added to the colored pipe resin, non-black pipe can last several years in outdoor storage. Non-black pipe is not recommended for permanent outdoor use. Black PE pipe has been stabilized with carbon black, which is the most effective ultraviolet stabilizer. PE pipe with carbon black UV stabilization (the normal black PE pipe), may be used indefinitely outdoors. Will HDPE pipe float in water?Yes, HDPE pipe has a specific gravity of about 0.95 so it will float. For underwater, anchored pipeline installations, it is important to specify the proper weights and spacing of the weights. Screw-anchors are a practical alternative. Whenever possible, an underwater pipeline should be installed in a trench with protective crushed rock cover. Can HDPE pipe be used in permanent above ground installations?Yes. In many mining and industrial applications, HDPE pipe has been installed above ground and has provided and continues to provide excellent service after 15 to 25 years (North America), with the potential to remain in service for many more years. How are WEHOLITE pipes and components joined?Weholite is joined by extrusion welding. Extrusion welding provides the piping system with leak free joints, eliminates gasket materials which are subject to chemical degradation, and creates an homogenous system. How can HDPE pipe be connected to pipe made from other materials (PVC, Ductile, Iron, Corrugated)?For non-pressure ‚'drainage' applications, flexible rubber couplings have been used for decades with success. These flexible couplings are made for joining all types of gravity flow drainage pipe, including transitions from one type or size of pipe to another. Is expansion and contraction of HDPE pipe a problem?No. All objects expand and contract. As with all materials, expansion and contraction must be taken into consideration when designing a HDPE piping system. The resistance to movement provided by friction between the pipe and its' embedment is usually sufficient to prevent thermal expansion and contraction. After HDPE has been buried and allowed to relax, will the pipe continue to expand and contract a great amount with temperature variations?No. When HDPE pipe is buried, the temperature of the system becomes much more stable than when it was above ground. Therefore it will exhibit far less dimensional change. Also, the friction between the compacted soil and the pipe offers resistance to movement. Buried HDPE pipe usually does not move after it is buried. How will using HDPE save money?Using HDPE pipe you create a leak-free system with an exceptionally long service life, that will save money annually on reduced leakage losses, improved water conservation, a reduction in the need for new water treatment plants, reduced warehousing requirements, a reduction in maintenance crews, reduced seasonal water-main breaks, less maintenance, and less rehabilitation and restoration. Savings will accrue for many years to come. |
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
