Minimum risk design, system safety

Design for Minimum Risk The system safety order of precedence dictates that, from the first stages of product or system design, the system should be designed for the elimination of hazards, if possible. Unfortunately, in the real world, this is not always practical or feasible. If an identified hazard cannot be eliminated, then the risk associated with it should be reduced to an acceptable level of hazard probability through design selection. 

If the design of a system (the facilities, equipment, work methods, etc.) does not achieve minimum risk, superior results with respect to safety cannot be attained, even if personnel and management factors approach the ideal. 

System safety should be involved in the PDR, typically making a presentation summarizing the safety effort to date, the DSFs in the system design, and the current level of mishap risk which the design presents. System safety provides, as a minimum, a subsystem hazard analysis (SSHA), SHA, safety assessment report (SAR), and final safety requirements for this review. 

The objective of system safety is to develop a system that provides acceptable minimum mishap risk. The basic system safety philosophy for achieving this goal is to confront hazards, mishaps, and risk at three different levels of safety defense. These levels of defense are engineered into the system design. This layer of protection philosophy is summarized by the following three safety precepts ... 

The intent of the SSP is to ensure that the system design meets applicable safety requirements, and that all hazards associated with the system are identified and eliminated, or controlled in a manner consistent with program objectives, constraints, and risks. The SSP also provides management visibility of safety risks inherent in the design and planned operations, and defines the process required for management to formally reduce and accept the system safety risks. Regardless of the type, size, or complexity of a system, there are specific items required to formulate an SSP. In order to exist as an entity, an SSP requires the following items, as a minimum ... 

Discussions in the process of developing consensus standards can be lively, positions taken by individuals can be strongly held and debated for hours, and many compromises are made. Some standards set forth only the minimum requirements on the subject covered. For example, the scope of ANSI/AIHA ZlO-2012. American National Standard— Occupational Health and Safety Management Systems, states This standard defines minimum requirements for occupational health and safety management systems (OHSMS). Also, if a standard is obsolete, using the standard as a design base may result in designing to obsolescence and perhaps unacceptable risk levels. 

Many techniques have been developed to reduce these risks to a minimum and this chapter looks at some of those techniques that are available to the designer and user of modem equipment. What is not dealt with is the other vital element in the interface - the operator - and the training necessary to ensure his/her safety and how it matches the equipment, the culture and the working methods of the particular organisation. Essentially the term work equipment encompasses any equipment used in the course of work. However, in this chapter work equipment will be considered in four major frmctional areas machinery, power tmcks, cranes and lifts, and pressure systems. 

It is clear that it would be possible to reduce marine accidents by good design, training, and operation in an appropriate systematic management system. As the public concern regarding maritime safety increases, more and more attention has been directed to the wide application of formal safety assessment of ships as a regulatory tool. It is believed that the adoption of such a tool in ship design and operation will reduce maritime risks to a minimum level. 

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