Failure internal sources

Common Cause or Common Mode Failure—Failure, which is the result of one or more events, causing coincident failures in multiple systems or on two or more separate channels in a multiple channel system, leading to system failure. The source of the common cause failure may be either internal or external to the systems affected. Common cause failure can involve the initiating event and one or more safeguards, or the interaction of several safeguards. 

Key factors of SCC. The stress applied on a metal is nominally static or slowly increasing tensile stress. The stresses can be applied externally, but residual stresses often cause SCC failures. Internal stresses in a metal can be due to cold work or a heat treatment. In fact, all manufacturing processes create some internal stresses. Stresses introduced by cold work arise from processes such as lamination, bending, machining, rectification, drawing, drift, and riveting. Stresses introduced by thermal treatments are due to the dilation and contraction of metal or indirectly by the modification of the microstructure of the material. Welded steels contain residual stresses near the yield point. Corrosion products have been shown to be another source of stress and can cause a wedging action. 

It is possible to modify a normal home refrigeration unit to remove the internal sources of ignition, but unless it is done by a person who knows precisely what to do and does it very carefully the result may not be as safe as one initially designed to be used for flammable material storage. The liability which could result from the failure to prevent an explosion by an improperly, locally modified unit makes this an imprudent economy measure. In addition, the... 

In general, complexity in the supply chain is made worse at an organisational level because of aggressive global and international sourcing of materials and products. This reduces the cost of goods sold. However, complexity adds substantial distance, time and dependence on the international logistics pipeline. These increase the risk of supply chain failures. 

The Department of Industrial Safety has been collecting and recording component failure data since 1978. For this purpose use is made of the following sources of information accessible (international) data-banks, literature and data... 

A 1-in (internal diameter) pipe is used to supply water to a low-pressure tank with an MAWP of 20 psig. The water is supplied through a regulator from a source with a maximum pressure of 100 psig. Determine the diameter of a conventional spring-operated relief required to protect the vessel from a regulator failure. Be sure to state clearly any assumptions and your justifications for them. 

Ruptures Large releases of very low frequencies. Typically vessel, tank pipeline or hose failures from internal, external, or third party sources and fire conditions (i.e., BLEVE conditions). 

Technology advances in electronics such as process control instrumentation systems, computer capabilities, programmable logic controllers, and the use of independent PC s (personal computers) at field locations for special dedicated functions present new challenges to incident investigation. Some of the advances are so rapid that the team may not have the internal expertise to determine failure scenarios, sequences, and modes. The suppliers and manufacturers of these high-tech devices are sometimes the only source of credible information on failure modes of these devices. 

Nord, Randall F. 1995. (Internal report) Source of ASTM D-2276 failure. 95/693. Sugar Land, Tex. Nalco/Exxon Energy Chemicals, L.P. 

The quantitative assessment of environmental impacts can be made using life-cycle assessment (LCA) methodology, which accounts for both inputs and emissions. LCA can be used to identify the major environmental impact categories and the sources of those impacts within a chemical processing plant. LCA can also be used to identify the major contributions to environmental impact within a product s life cycle. Impact scores derived from LCA can be used along with economic assessment scores and social indicators to provide indicators of overall sustainability of processes and products. Economic assessments are often limited through failure to account for all internal costs and especially the external costs associated with waste. 

While the mechanisms of international influence on the acid rain policies of CEE countries were broadly similar, these states responded with different compliance strategies depending on a range of domestic political and economic factors. In order to understand the sources of success and failure of acid rain policies in the region, we need to look also at the interplay between international and domestic policy incentives. 

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