First-time safe systems

The system safety effort strives to be proactive by very early identification, analysis, and control of hazards to produce first-time safe systems. 

The continuing and growing need for first-time safe systems will require system safety efforts for more and more products and services, in government and in private industry. These efforts must include... 

System safety may grow as a separate discipline or the system safety effort may be absorbed into the mainstream of industrial safety, loss prevention, risk management, loss control, or some other program. A new name or buzzword may appear. Nevertheless, the need for first-time safe systems and for the application of system safety principles, tools, and techniques to systematically identify, analyze, and control hazards as early in the life cycle as possible (with continuing efforts throughout the life cycle) will continue to grow indefinitely. 

The roots of the system safety effort extend back at least to the 1940s and 1950s. Accurately tracing the early transition from the traditional trial-and-error approach to safety to the first-time safe effort that lies at the heart of system safety is really impossible, but such a transition occurred as both aircraft and weapon systems became more complex and the consequences of accidents became less acceptable. 

At the working level, system safety tasks are normally performed by a system safety working group (SSWG). One of the reasons that a system safety working group or a team approach is generally used in system safety efforts is that multiple talents and disciplines are required in order to provide for the first-time safe, efficient operation of the entire system (Fig. 2-6). 

System safety tools and techniques currently used primarily in the aerospace, weapons, and nuclear industries offer great potential for meeting these challenges. The systematic application of system safety fundamentals early in the life cycle to produce first time safe products and services can provide significant, cost-effective gains in the safety effort in transportation, manufacturing, construction, utilities, facilities, and many other areas. 

That this approach was not acceptable for certain programs— such as nuclear weapons and space travel—soon became apparent, at least to some. The consequences of accidents were too great. Trial-and-error and fly-flx-fly approaches were not adequate for systems that had to be first-time safe. 

In particular, membrane bioreactors (MBRs) are today robust, simple to operate, and ever more affordable. They take up little space, need modest technical support, and can remove many contaminants in one step. These advantages make it practical, for the first time, to protect public health and safely reuse water for non-potable uses. Membranes can also be a component of a multi-barrier approach to supplement potable water resources. Finally, decentralization, which overcomes some of the sustainability limits of centralized systems, becomes more feasible with membrane treatment. Because membrane processes make sanitation, reuse, and decentralization possible, water sustainability can become an achievable goal for the developed and developing worlds. 

The impact of this paper cannot be underestimated. For the first time, it was demonstrated that accurate structural energies could be calculated and used to make predictions about the solid state. This work led to an enormous interest in utilizing pseudopotentials and density functional theory for a wide variety of systems including liquids, clusters, defects, etc. [9]. It also laid the foundation for ab initio molecular dynamics [10]. Since structural energies could be evaluated accurately, it was apparent that interatomic forces could also be calculated within this formalism and could be used in molecular dynamics simulations. It is safe to assert that this paper established the PDFM as the method of choice for the elucidation of the electronic structure of condensed matter. 

At first glance, this system would look relafively safe. It has separate high- and low-pressure subsystems. All the components have been proofed to 1.5 times MOP. Even the design burst pressure is significantly higher than what we expect to see in this system. 

Like the first edition, the book is aimed at working engineers who know that they need to build safe systems, but aren t sure where to start. They don t want to waste a lot of time sorting through the mountain of safety books that are more theoretical than practical or too narrowly focused. This book is for those looking for a single, comprehensive. 

The first table. Table 7, shows the influence of the various factors which may be grouped under the heading of Functional Testability. The importance of fault detection and failure location was discussed in section 5 however, as Table 7 shows, these factors extend beyond the detection and location of faults. The need for special test equipment influences logistic time. The presence of test points and BITE also affects preparation for changeover or repair because of the need to ensure a safe system state before proceeding with these activities. 

So, in 1974, we saw for the first time, the Health and Safety at Work Act of Parliament (HSW), which places general duties on employers and the self-employed to ensure that employees and others who may be affected by the work of their undertaking are not, so far as is reasonably practicable, exposed to risks to their health and safety. Particirlarly important, this includes the provision of safe systems of work, supervision and training. 

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