AWWA M PE Pipe – Design and Installation. Document Language: English; Published By: American Water Works Association (AWWA); Page Count: PE Pipe – Design and Installation MANUAL OF WATER SUPPLY PRACTICES M55, First Edition AWWA MANUAL M55 First Edition American Water Works. AWWA M55 is not a standard, but rather a design manual according to the recommendations of the American Water Works Association (AWWA) covering all .
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For an occasional surge event: A chemical stabilizer system is typically added to the PE to prevent the generation of these free radicals. Mechanical Compression Fittings Mechanical compression fittings typically have a body that is a pressure-containing component that fits over the outside diameter of the pipe, a threaded compression nut or follower gland with bolting arrangement, and elastomeric seal rings or gaskets. Pipe and joining equipment manu- facturers should be consulted for information about joining procedures, training, and appropriate tests for demonstrating joint integrity.
The resultant load transferred to the pipe depends on the vehicle weight, the tire pressure and size, vehicle speed, surface smoothness, pavement, and distance from the pipe to the point of loading. In some cases, entrapped air that is rapidly vented can greatly raise fluid pressures causing damage to pipe a n d o r pipe components. Stress relaxation is another unique property arising from the viscoelastic nature of PE.
Off-highway vehicles may be considerably heavier than H20 trucks, and these vehicles frequently operate on unpaved roads, which may have uneven surfaces.
This performance level provides a consid- erable margin against the potential for environmental stress-cracking failure in the field. Spangler proposed that the time-lag factor ranges from 1. The influence coefficient gives the portion or influence of the load that reaches a given depth beneath the corner of zy the loaded area. In the figure below an example can be seen of the obtained results i.
The bend-back test evaluates the inside pipe surface for brit- tleness. The primary UV stabilizer used aewa the PE pipe industry is carbon black, which is the most effective additive capable of inhibiting UV induced reactions.
Research in the area of slow crack growth combined with continual advancements in material science have resulted in HDPE piping products that when manufactured and installed in accordance with these standards are designed to provide sustained resis- tance to slow crack growth phenomena such as environmental stress cracking.
For the reasons stated previously, a combined internal and external loading analy- sis is not necessary for Awda pipe.
Simultaneously heating and melting the pipe end and the fitting socket. Before unloading the shipment, there must be adequate, level space to unload the shipment. A saddle fusion machine that has been designed for this purpose is required. Working pressure rating WPR.
Pe Pipe Design And Installation (M55) by AWWA Staff
This aspect of PE pipe means that cathodic protection is not required to protect the long-term integrity of the pipe even in the most corrosive environments. Reinforcing material is used only for mechanical protection, not to increase the design pressure rating of the fitting.
Recurring surge pressures may be caused by normal pump start-up or shut-down and normal valve opening or closure. The dashpots represent fluid elements of the polymer that respond to load much as a New- tonian fluid.
Pe Pipe Design And Installation (M55) (Awwa Manual)
There is essentially no dead surface load imposed over the pipe and no groundwater above the surface. Even cyclic pressure surges of up to percent of the operating pres- sure of the PE water pipe system do not exceed the critical strain limit for these highly ductile materials. Multiply the veloc- ity times the pipe average, Di, to get the vDi term, which equals 9. This is because of the increased confinement of the embedment soil by the surrounding soil.
Melting the component ends. The stiffener keeps the pipe from col- lapsing from the compression loads, which could result in leakage or even failure of the restraining feature if the fitting provides restraint.
Therefore, the pipe producer gener- ally monitors those process control variables that are determined as quality critical. Specialized equipment that straightens and rounds the pipe at the time of installation may be required. Provisions for flotation of shallow cover pipe have been provided. Arching tends to transfer some of the weight of the backfill to the soil beside the pipe and thus reduces the load on the pipe.
Using this protocol, stress-rupture data at a specific temperature is gathered over a 10, hour period. Thus, the designer need not perform calculations on pipes within the design window. These values are conservative for use with larger diameter pipe, and any error incurred with their use for smaller diameter pipe is insignificant. Insert fittings are also used to join smaller PE pipe and tubing. However, some fit- tings may require specialized tools for installation?
To understand the significance of this statement, one must first understand the nature of slow crack growth and pipe failure in general. Eq can be solved for the head loss. Electrical Properties PE is an excellent insulator and does not conduct electricity. Ring deflection is an essential response of flexible pipes to soil load.
Lifting equipment, such as cranes, extension boom cranes, and side boom tractors, should be hooked to wide web choker slings that are secured around the load or to lifting lugs on the component. At higher flow velocities typical of potable water distribution, there is no erosional effect on PE pipe.
The equiva- lent radius is given by: The following equation may be used to determine the allowable negative pressure or external pressure an unconstrained or unsup- ported pipe can resist without collapsing: Numerous studies have been conducted over the years relative to the biological implications of PE pipe.