Maintenance Through Inspection And Monitoring

5 Smart Sensing of Corrosion with Fiber Optics 448 

In the modern business environment, successful enterprises cannot tolerate major corrosion failures, especially those involving unscheduled shutdowns, environmental contamination, personal injuries, and fatalities. For this reason, considerable effort must be expended on corrosion control at the design stage and also in the operational phase. Typically, once a system, a plant, or any piece of equipment is put into service, maintenance is required in order to keep it operating safely and efficiently. This is particularly true for aging systems and structures, many of which may operate beyond their original design life. 

Inspection techniques for the detection and measurement of corrosion range from simple visual examination to nondestructive evaluation. Significant technological advances have been made in the last decade. For example, the combined use of acoustic emission (AE) and ultrasonics (UT) can, in principle, allow an entire structure to be inspected and growing defects to be quantified in terms of length and depth. Advanced corrosion monitoring methods have been developed that have both online capabihty and the abihty to detect problems at an early stage. The oil and gas production and petrochemical industries have assumed a 

Considering the many complex forms and mechanisms of corrosion damage, the limitations of individual plant inspection and monitoring techniques are considerable. The large number of variables involved also implies that no single method can be expected to be satisfactory in all possible conditions and environments. Many of these variables are described in other parts of the book. The factors involved in the corrosive environment have, for example, been introduced in Chap. 5, Corrosion Failures. 

Inspection normally refers to the evaluation of the quality of some characteristic in relation to a standard or a specification. As products and their manufacturing processes have grown more complex and been divided among many departments, the job of inspection has also become complex and distributed. A flow diagram is useful for showing the various materials, components, and processes that collectively or sequentially make up the system. The main purpose of inspection is to determine whether components, systems, or products conform to specifications. Inspection consists of the following series of actions  

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Other technologies that have been used for atmospheric corrosion sensing include electrical resistance (ER) sensors and more recently fiber-optic sensing systems. Additional information may be found on this topic in Chap. 6, Corrosion Maintenance Through Inspection and Monitoring. 

Corrosion Maintenance through inspection and Monitoring 451 6.5.2 Optical fiber basics... 

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