An Industry View of Mechanical Integrity

Ken Robertson, president of Exxon Chemical America, discussed protective programs or mechanical integrity programs in a keynote address at the Chemical Manufacturers Association s Plant Inspection and Maintenance Forum in 1990. Indicating that public expectations are increasing, Mr. Robertson noted that there is less tolerance for oil and chemical spills as well as tragic plant safety incidents. [7] 

The Exxon president reviewed some of his company s process safety management practices relating to maintenance  

safety critical systems must be reliable. These systems control releases in the event of accidents, ft s necessary to have a critical analyzer, instrument and electrical system test program. This should consist of preventive maintenance and alarm and trip device testing for panel alarms, emergency isolation valves and other critical components. 

procedures must be in place to control defeating safety critical systems. Before taking these systems out of service for any length of time, there must be proper authority, communication and detailed contingency planning. 

Regular, comprehensive inspections to ensure the safe condition of site equipment is another important consideration. There must be clear lines of responsibility for inspection and maintenance of crucial containment systems. A formal system must be in place for documenting recommendations and communicating them clearly and quickly to the appropriate managers in the organization. 

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Offers an industry view of mechanical integrity and details on inspections and tests... 

The more important factors from an industrial point of view are a high flux or productivity and a high selectivity or separation eflectiveness. It is here that asymmetric membranes find more application, due to their high flux. When the same material forms two layers differing in their structure, with a thin active dense skin layer associated with another layer that acts as a mechanical support and has no significant resistance to mass flux, the resulting membranes are called integral. 

The software tool WOMS has proven to be appropriate and effective to support the modeling process in an industrial environment. WOMS has different capabilities to present the work process model to the engineer. These views have shown to be helpful to develop, better understand and analyze the work process. However, the complexity of the work process model often hinders transparency. Hence, additional structuring and abstraction mechanisms have to be developed and integrated in WOMS in on-going research work to solve this problem. 

Research on the impact strength of adhesively bonded joints has been recently carried out very often. As mentioned above, the reason is due to the increase of demand from industries and the progress of computer technologies. The tendency seems to continue in the near future. For the purpose, the integration of finite element analyses and strength criteria becomes important. Approaches using cohesive zone models are very promising for actual applications such as car structures because the approaches are suitable for finite element analyses based on explicit schemes. In contrast, closed-form approaches are necessary from an academic point of view and should be also taken for the impact problem of adhesively bonded joints to understand the nature of joint mechanics. Unfortunately, only few studies on the closed-form analyses have conducted already, so that more research should be done in the future. 

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