Underground piping

Vinyl ester resins generally offer mechanical properties superior to those of polyester matrices but at an increased cost. Vinyl esters are chemically similar to epoxy resins but are manufactured via a cold-curing process similar to that used in the manufacture of polyester resins. Vinyl esters offer superior resistance to water and chemical attack and are used in such appHcations as underground pipes, tank liners, and storage tanks (see Vinyl polymers). 

Examples of the sacrificial-anode method include the use of zinc, magnesium, or aluminum as anodes in electrical contact with the metal to be protected. These may be anodes buried in the ground for protection of underground pipe lines or attachments to the surfaces of equipment such as condenser water boxes or on ship hulls. The current required is generated in this method by corrosion of the sacrificial-anode material. In the case of the impressed emf, the direct current is provided by external sources and is passed through the system by use of essentially nonsacrificial anodes such as carbon, noncor-rodible alloys, or platinum buried in the ground or suspended in the electrolyte in the case of aqueous systems. 

At the Lipari Landfill site in New Jersey, the gas venting system installed in 1983 consisted of two underground 4-inch (10-cm) perforated PVC pipes and five vent risers. Two parallel PVC pipes were installed 200 feet apart prior to cap emplacement during the period of wall construction and were placed about 3 feet beneath the finished grade. The vent risers were connected to the buried manifold pipes and consisted of open pipe installed perpendicular to the underground pipes and the ground surface. Filters were not attached to the riser exit points (U.S. EPA, 1987). 

Failure of cooling water piping in sequence 17 was dominated by soil consolidation lailure of underground piping. The pipe is subject to non-ductile cracking during extremely cold w eather. 

In March 1877, New York inventor Birdshill I lolly introduced the Holly Steam Combination System to provide heat and power using steam distributed through an underground piping network. The first... 

Considerations such as these can lead to unexpected problems where waters are mixed, either at a treatment works or in a tidal zone within a distribution network into which two sources are fed separately. Within the author s experience, problems of an erosion attack on copper pipe have occurred at fittings, especially where the ends of the copper tube have been belled out to meet the requirements of the bye-laws for underground pipe, with mixtures of waters that were satisfactory when supplied separately. 

The corrosion of underground pipes and cables caused by the electrolytic action of stray currents from d.c. electric railway and tramway systems has long been a serious problem. Regulations limiting the maximum potential between tramway rails and neighbouring buried structures and the maximum potential difference between points on the rail systems have been in operation in the UK since 1894 and in Germany since 1910 . 

The high chemical stability of many polymers is both a blessing and a curse. Heat resistance, wear resistance, and long life are valuable characteristics of clothing fibers, bicycle helmets, underground pipes, food wrappers, and many other items. Yet when those items outlive their usefulness, disposal becomes a problem. 

Fig. 4-2 a) Load-testing profile of flexible and rigid underground pipes. 

Considering reducing the water mains pressure or isolating areas when not in use, if leaks and unaccountable losses are a problem from underground piping systems and so on... 

Additional underground pipe protection shall be used in conjunction with an effective educational program [para. GR-5.2.2(d)], continuing surveillance of pipelines (para. GR-5.12.1), pipeline patrolling (para. GR-5.12.2), and utilization of programs that provide notification to operators regarding impending excavation activity, if available. 

This Appendix provides criteria for detection, grading, and control of hydrogen gas leakage in pipelines and underground piping in process units. 

Site facilities such as underground piping preclude practical trench excavation. 

Develop a source elimination program to detect leakage from aboveground tanks and underground piping in the early stages of LNAPL release and... 

Eventual conversion of underground piping to aboveground piping ... 

A large facility connected to the city water supply should have two independent connections off different branches of the city underground piping. 

Materials acceptable for underground piping use include ductile iron, fiberglass-reinforced epoxy plastic, polyethylene, polyvinyl chloride, reinforced concrete, and carbon steel. Plastic pipes are not acceptable in areas subject to solvent exposure. 

Drainage out of process structure/area into an external containment area. The drainage may be achieved either by surface swales or berms, ditches or trenches, or via an underground piping system... 

Flushing of new underground piping system, including branches from existing or new underground mains to devices, should be wit-... 

Underground piping Flush system following the guidance in Chapter 9. Yearly... 

Above ground piping should be examined to determine its condition and to verify that proper drainage pitch is maintained. Underground piping should be spot-checked for deterioration at least every five years. 

Damage to underground pipes, cables, and other infrastructure due to the breakdown of unprotected metal, cement, and other materials. 

The structure-to-electrolyte potential of corrosion protection systems used to protect aboveground tank bottoms and connecting underground pipes must be inspected annually. 

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