Safety engineering mechanical systems

Lemaire, M. 1997 Reliability and Mechanical Design. Reliability Engineering and System Safety, 55, 163-170. 

Industrial fire protection and safety engineers attempt to eliminate hazards at their source or to reduce their intensity with protective systems. Hazard elimination may typically require the use of alternative and less toxic materials, changes in the process, spacing or guarding, improved ventilation or, spill control or inventory reduction measures, fire and explosion protective measures - both active and passive mechanisms, protective clothing, etc. The level or protection is dependent on the risk prevalent at the facility versus the cost to implement safety measures. 

Structural health monitoring (SHM) is a process for evaluation of the structural safety status from structural response measurements. The ultimate goal is to develop an economical and non-destructive system for the earliest possible detection of damage. It has been attracting much attention in the past two decades. A tremendous amount of efforts have been dedicated in this area [15,18,19,25,51,52,68,69,77,101,103,106,138,142,143,149,160,168,174,185], [186,195,201,204,228,238,244,246,261,267,268,281,282]. Comprehensive literature reviews on the development of SHM can be found in Doebling et al. [69] and Sohn et al. [247] and there were also a number of workshops, [1,44,187], for example, and special issues of journals, e.g.. Journal of Engineering Mechanics in July 2000 [90] and January 2004 [26] and Computer-Aided Civil and Infrastructure Engineering in January 2001 [278] and May 2006 [22]. 

When performing an FMEA on mechanical, fluid or electrical system, failure modes of components such as pipes or resistors are generally understood, likely to happen and their consequences may be studied. A component is supposed to fail, due to some reason as wearing, aging or unanticipated stress. The analysis may not always be easy, but at least, the safety engineer can rely on data provided by the component manufacturer, results of tests and feedback of experience when available. 

SAV-implemented fault tolerance The systems engineer or system safety practitioner should be fully cognisant of the SAV-implemented fault tolerance mechanisms. These should be largely driven by system-level fault tolerance requirements and feed to the SAV team for implementation. 

Using the task analysis as a starting point, the System Safety Engineer can assist (via Step 3) the HF specialist to identify feasible types of error in the task and record the possible consequences of the error, and the safeguards and recovery mechanisms in place to prevent/detect/correct them. Be explicit in the recording of any assumptions (e.g. escalating or containing factors) which influence decisions made. 

NOTE It could be a process engineering mechanism such as the size of vessels containing hazardous chemicals, a mechanical engineering mechanism such as a relief valve, a safety instrumented system or an administrative... 

As stated in the preceding chapter, safety analysis of a technical system is systems analysis governed by safety engineering aspects. Its essential purpose is to ascertain hazards which could result from a technical system and to deal with questions of possible reduction of such hazards. In this context the analysis will view the technical system as the sum of all elements in a state of reciprocal action and the conditions resulting from the combined action of these elements. When dealing with the technical system, the aim is to show the structures, i.e., to identify the control and regulating mechanisms, to understand states of equilibrium, to ascertain problems, and to furnish a dear picture of the consequences of failures of regulating variables. 

The discussion on hazardous area standards is concluded with the recommendation that the applicable standard part must be read thoroughly before starting any equipment selection. Since area classification is mainly carried out by mechanical and safety engineers, good coordination is helpful. Gas detection systems for hazardous locations is another area of concern for instmmentation and control engineers so brief discussions on combustible gas detection systems will be dealt with in the next clause. 

The system is the combination or interrelation of hardware, software, people, and the operating environment. In system safety engineering, you must look at the system from cradle to grave. In other words, the system life cycle is the design, development, test, production, operation, maintenance, expansion, and retirement (or disposal) of the system. A nuclear power plant is one large system with operators, pressure subsystems, electrical and mechanical subsystems, structural containment, safety systems, etc. A far simpler example is a boy riding his bike. The bike, the boy, the street (with all its traffic conditions), the weather, the time of day, and even other children make up the system of boy on his bike. 

The history of establishing the study program Safety of Technical Systems at Faculty of Mechanical Engineering, Technical University in Kosice, is related to this trend as well. However, activity indicative of coincidence preceded this trend, but since I do not believe in coincidences, I have the honour of stating, It probably was meant to be so ... 

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