Avoidance catastrophic failure

Avoid catastrophic failure of engineering materials Adequate redundancy of instrumentation and control systems... 

The choices of the construction materials used in a chemical plant are some of the most important decisions a process designer will make. Inherently safer plants will be designed by people who take advantage of the latest and best available technology to avoid catastrophic failure (Liening, 1986a,b). It is not possible for most process designers to be experts in the field of corrosion. Therefore, it is necessary to make use of the resources available. 

In all these cases the problem can be solved by adding suitable rubber modifiers to the homopolymer matrices. These will induce, under impact loading, locally diffused microscopic mechanisms of deformation, making the matrix capable of dissipating large impact energies, avoiding catastrophic failure. 

While ideally structures should be designed and fabricated so that environment-sensitive cracking is avoided, in practice it is sometimes necessary to live with the problem. This implies an ability to detect and measure the size of cracks before they reach the critical size that may result in catastrophic failure. Such inspection has important implications for plant design, which should be such as to allow inspection at relevant locations. The latter are regions of high residual stress (welded, bolted or riveted joints) and regions of geometrical discontinuity (notches, crevices, etc.) where stress or environment concentration may occur. 

For unreinforced masonry, the failure mode is based on tensile cracking. To avoid the resulting catastrophic failure, the wall must remain elastic. Thus, pa = 1.0... 

Class 11 flowmeters have no wetted moving parts to break and are thus not subject to catastrophic failure. However, the flow surfaces such as orifice plates may wear, eventually biasing flow measurements. Other disadvantages of some flowmeters in this class include high pressure drop and susceptibility to plugging. Very dirty and abrasive fluids should be avoided. 

Perfluorinated solvents can be handled like any other conventional liquids, and in some cases additional safety benefits may arise from their non-existant or very low flammability. Similarly, the use of nonflammable C02 will result in largely reduced risks of ignition or explosion. These factors make both media particularly attractive for oxidation chemistry. The handling of compressed C02 requires suitable high-pressure equipment and—as with all compressed gases—appropriate safety precautions have to be taken in order to avoid any potential hazards arising from catastrophic failure of the equipment. Such measures are, however, readily met on a laboratory or industrial scale and standard equipment is commercially available from many vendors (Jessop and Leitner, 1999). 

This chapter has reviewed the performance of CMCs under conditions of thermal shock. It has been shown that CMCs exhibit superior resistance to thermal shock, compared with their monolithic counterparts, as catastrophic failure can always be avoided. Resistance to higher temperature differentials and property retention after the onset of thermal shock cracking (especially in fibre-reinforced CMCs) can be realised, provided that the mechanical and thermal properties of CMCs are optimised by careful choice of their constituents. 

The most important materials failure to avoid in the design of metal equipment is sudden catastrophic failure. This occurs when the material fractures under impulse instead of bending. Catastrophic failure can cause complete destruction of piping or equipment, and can result in explosions, huge spills, and consequent fires. Causes of some of the more common types of catastrophic failures are ... 

The use of harder materials enhances wear resistance, but this conflicts with achieving adequate ductility to avoid catastrophic brittle failure, so these two effects must be balanced. Wear-resistant materials can be divided into three groups (1) abrasion-resistant steels, (2)... 

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