Pipelines failures, causes

The potential for pipeline failure caused either directly or indirectly by corrosion is probably the most common hazard associated with steel pipelines. The corrosion index was organized in three categories to reflect three types of environment to which pipelines are exposed, i.e., atmospheric corrosion, soil corrosion, and internal corrosion. Table 4.3 contains the elements contributing to each type of environment and the suggested weighting factors. 

Pipeline Reliability An Investigation of Petroleum and Natural Data on frequency and cause of pipeline failures Data is specific to submarine and cross-country 49. 

This article presents an overview of the causes and frequency of failures for submarine and cross-country pipelines handling oil and natural gas. It gives several tables and charts which include information on the type of pipeline, the cause of the failure, and the number of failures. Data from failures in the US and the North Sea are included. Failure rates based on the total length of piping are calculated. 

Embrittlement of service materials. The low temperatures inside storage tanks and transmission pipelines may cause significant susceptibleness of the structural material in vibrations and shocks. Mild steel and most iron alloys, at LH2 temperatures, lose their ductility being liable to increased risk of mechanical failure [50]. 

Gouges, grooves, and notches have been found to be an important cause of pipeline failures, and all harmful defects of this nature must be prevented, eliminated, or repaired. Precautions shall be taken during manufacture, hauling, and installation to prevent the gouging or grooving of pipe. 

Texas, USA 1965 Propylene Pipeline failure in polypropylene polymerization plant caused 3M damage in an explosion and fire FB CVE... 

A liquid release offers the potential for the formation of an aerosol (mist). Aerosol formation is influenced by mechanical force (acceleration) and fluid properties, such as the material s surface tension. Additionally, in some systems the pressure, because of static head, may be adequate to cause some aerosol formation and must be considered. Examples of liquid releases include an accidentally opened storage tank drain valve, a pipeline failure downstream of a pump, a damaged nozzle at the base of a liquid knockout drum, or the failure of a loading hose. 

Historical experience with pipeline failures reveals that the two single most common causes for failures are outside forces and corrosion. There are variations in individual systems. Accordingly, a significant part of the effort in achieving better pipeline safety is corrosion control and damage prevention directed at outside forces. The other causes of pipeline failure, individually, contribute to a much smaller proportion of pipeline incidents, but they are still addressed because their aggregate contribution matters. 

Low-pressure gas distribution pipeline failures result in leaks that undetected might ignite and cause an explosion. The number of leaks because of corrosion was mains... 

J.S. Mandke, Corrosion causes most pipeline failures in Gulf of Mexico, Oil GasJ. 29 (1990) 40-44. 

Corrosion of most common engineering materials at near-ambient temperatures occurs in aqueous (water-containing) environments and is electrochemical in nature. The aqueous environment is also referred to as the electrolyte, and, in the case of underground corrosion, it is moist soil. Corrosion is a common form of structure degradation that reduces both the static and cyclic strength of a pipeline. There is always the chance that pipelines could leak or rupture, and a pipeline failure can cause serious human, environmental, and financial losses [3-5]. 

Table 4. Probability of accidental scenarios caused by pipeline failure mode puncture.

Stress-corrosion cracking (S.C.C.) is a well-known cause of underground oil and gas transmission pipeline failures [11]. Stress-corrosion cracking of cathodically protected pipelines originates on the outer pipe surface, most commonly at areas where the coating is disbonded (i.e., no longer attached to the surface of the steel... 

A schematic diagram summarizing failures that led to the gasoline pipeline rupture and fire in Whatcom Faiis Park. This accident was due to a combination of pipeline damage (caused by poorly supervised excavation work around the pipeline several years earlier), inadequate non-destructive inspections of the pipeline, a wrongly specified pressure relief valve, inadequate investigation of valve control problems, and uncontrolled software upgrades ( SCADA" was the computer-based control system). 

Malo JM, Salinas V, Uruchurtu J. Stray current corrosion causes gasoline pipeline failure. Materials Performance, 1994 33 63. 

There are many causes and contributors to pipeline failures. The U.S. Department of Transportation (DOT) Research and Special Programs Administration, Office of Pipeline Safety (RSPA/OPS) compiles data on pipeline accidents and their causes. Tables 12.4 to 12.6 summarize the results collected during a two-year period (2002 and 2003) for respectively, natural gas transmission and gathering, hazardous liquid transmission, and natural gas distribution. 

Introduction. In the natural gas industry, MIC has been estimated to cause 15 to 30 percent of corrosion-related pipeline failures. The growth of bacteria on surfaces in cooling and process-water systems can lead to significant deposits and corrosion problems. Once the severity of these problems is understood, the importance of controlling biofilms becomes quite clear. 

Hydrate formation is possible only at temperatures less than 35°C when the pressure is less than 100 bar. Hydrates are a nuisance they are capable of plugging (partially or totally) equipment in transport systems such as pipelines, filters, and valves they can accumulate in heat exchangers and reduce heat transfer as well as increase pressure drop. Finally, if deposited in rotating machinery, they can lead to rotor imbalance generating vibration and causing failure of the machine. 

As a pipeline is heated, strains of such a magnitude are iaduced iato it as to accommodate the thermal expansion of the pipe caused by temperature. In the elastic range, these strains are proportional to the stresses. Above the yield stress, the internal strains stiU absorb the thermal expansions, but the stress, g computed from strain 2 by elastic theory, is a fictitious stress. The actual stress is and it depends on the shape of the stress-strain curve. Failure, however, does not occur until is reached which corresponds to a fictitious stress of many times the yield stress. 

Much of the damage and loss of life in chemical accidents results from the sudden release of material at high pressures which may or may not resiilt from fire. Chemical releases caused by fires and the failure of process equipment and pipelines can form toxic clouds that can be dangerous to people over large areas. 

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