Safety and availability

The concept of safety has different practical implications depending on the nature of the activity. The safety of railway traffic is particularly - and even primarily - about the capability of stopping it. When there are no trains running, the danger associated with circulation is in itself removed. 

There is also an emergency procedure, the warning radio signal, which orders all trains in the area to stop where the signal is emitted. 

The literature rarely distinguishes between safety and reliability. This close relationship, not to say causal, between the two is almost never questioned. 

Reliability ensures safety the danger comes from failures. 

What is quietly put aside with the concept of reliability, is that all events that we call failures are not equally undesirable. However, are some failures more desirable than others The problem is immediately transferred to safety as absolute reliability cannot be achieved. 

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Apply an open and objective system of controlling the use, safety and availability of pesticides. 

The advantages and disadvantages of various types of reactor outlined in this section are summarized in Table XI. The choice of a suitable reactor generally depends upon these characteristics, as well as cost, safety, and availability considerations. 

Inert solvents, with neither acidic nor basic properties, allow a wider range of acid-base behavior. For example, hydrocarbon solvents do not limit acid or base strength because they do not form solvent acid or base species. In such solvents, the acid or base strengths of the solutes determine the reactivity and there is no leveling effect. Balancing the possible acid-base effects of a solvent with requirements for solubility, safety, and availability is one of the challenges for experimental chemists. 

Wilkinson, S. Proceeding of the Advisory Committee on Blood Safety and Availability US Public Health Service, 1999 58-64. 

Use hydroponic grow containers that have small mesh holes so none of the mixture will escape through the sides. Remember ease, safety, and availability should be considered when determining the best medium to use. Some stores only sell certain items during seasonal times of the year. If this is a problem for you, simply purchase your critical items annually. 

Chapel HM. Safety and availability of immunoglobulin replacement therapy in relation to potentially transmissable agents. lUIS Committee on Primary Immunodeficiency Disease. International Union of Immunological Societies. Clin Exp Immunol 1999 118 29-34. 

For reasons of safety and availability as well as for environmental reasons, Brewer dismissed liquid methane as an inferior choice. He argued that, since civil commercial aviation is a truly international business, with airplanes refueling in New York, Rome, Tokyo, Jeddah, Warsaw, and Karachi, a future synthetic aviation fuel must be equally international— locally producible, with uniform characteristics everywhere. This is no problem as long as petroleum is cheap, and at the time kerosene and other hydrocarbon fuels were available at low cost all over the world. But aircraft makers, who have to think decades ahead when planning the useful life of airplanes, must face the fact that, beginning sometime in the period 2010-2020, petroleum may cease to be cheap. Brewer contended that it was going to be necessary to develop a new generation of synthetic aviation fuels that would be available everywhere around the world. 

Assurance of rehability and continued safety, and availability, requires a quantitative assessment of the system in its projected future state. For this assessment, appropriate quantitative models are needed for estimating the accumulation of damage (in size and distribution) over its projected period of operation. The outcome of this assessment then serves as the basis for decisions on its suitability for continued service as reflected in Fig. 10.1 by the labels Reliable, Conditioned Reliability, and Not Reliable. A system judged to be reliable would be accepted for unrestricted operation until the next scheduled maintenance, the one with conditioned reliability would be subjected to operational constraints, and the one deemed to be... 

Due to these unique properties, the relative safety and availability, some amino-polysaccharides will likely find, sooner or later, specific applications either in processed foods, special dietary or medical foods or in pharmaceutical preparations. 

The safety and availability of a set of equipment used for a safety instrumented function may benefit from testing. However, that depends on redundancy and how often the demand occurs. Three modes of operation have been defined in lEC 61508 for equipment providing a safety instrumented function continuous demand mode, high demand mode and low demand mode. This book will use the lEC 61508 definitions to designate those three different situations. 

Like other components in a safety instrumented function, diagnostics can improve the safety and availability performance of a final element. Several diagnostic techniques are given in Table 11-2. 

The self-diagnostic capability of a safety instrumented function is a critical variable for safety integrity verification. Good diagnostics improve both safety and availability. Detection of component failures is done by two different techniques classified as reference or comparison. 

Typical carrier gases include helium, nitrogen, argon, hydrogen, and air. Which gas to use is usually determined by the detector being used, the sample s matrix, or based on safety and availability. 

TVO has the philosophy of rolling 40 years plant lifetime . This requires that the technical condition of plant is kept at good level and maintenance and modernisation measures are conducted at right time by a cost-effective way, controlling the O M costs. PSA, modem maintenance analyses methods and operation experience are used to allocate maintenance measures to right components and to keep up the desired plant safety and availability level. 

Siemens Nuclear Power GmbH has developed and qualified iimovative methods and tools which allow to reduced service costs while maintaining high standards of safety and availability. The functioning capability and readiness for function of valves are proved and ensured by the integrated valve concept. Basic elements are ... 

The reliability of the function of valves and actuators defines the safety and availability of the power plants. 

Safety and Availability - Verification of readiness for function - Reduction of mistakes during maintenance activities - Immediate evaluation of measurement... 

Economically, cost-effective performance of valve maintenance means performing and bundling of all individual activities under the umbrella of an experienced service provider which act as a main contractor. The great advantage of such a contract for the customer is to order the complete maintenance service on a fixed price which is lower as the total cost obtained from a large number of individual services. Competent and reliable subcontractors which are familiar with special features of components are involved to ensure good quality of work. Under such conditions the mutual cooperation can preserve the maintenance competence and know-how to ensure the safety and availability as long as the nuclear power plant is in service. Effective improvements based on process analyses can also be implemented. 

The main idea for automation is to make the future plant less sensitive to human errors. In the EPR the required degree for automation has been fixed by comparison of the French and German existing solutions all elements which have an influence on availability or the human failure risk considering the overall safety will be automated in the future EPR (e g. main coolant pump automatic start up sequence to avoid a potential human failure considering the complexity of the starting procedure and the consequences on safety and availability in case of a pump failure, automatic start of the third main feedwater pump when required)... 

When all the answers so far where no there seems to be no other possibility left than performing system simulation. The available methods have been discussed in Section 2.3. In any case one should recognize that this requires both dedicated tools and the reliability technology expert to master the tool. As an advantage of simulation models it should be emphasized that these models are useful for learning a lot with respect to the safety and availability performance of a system. For sub-system owners this can be an interesting perspective. 

Burner Management Systems Solutions Increase the Safety and Availability of Your Com-bustion Process Invensys Triconex Schneider electric Technical write up. 

The aim of this paper Is to outline a method of using off the shelf programmable electronic systems (PES) In a failsafe redundant configuration with which It Is hoped to achieve the safety and availability requirements for a refuelling control system. 

The purpose of the pipeline control system is to control and monitor the transportation of crude oil through two pipelines. For safety and availability reasons a redundant process controlling computer system is used. An important component of the pipeline control system is a microprocessor controlled remote action system which transmits all measured values and commands ... 

Kleinman S, King MR, Busch MP, Murphy EL, Glynn SA. The National Heart, Lung, and Blood Institute retrovirus epidemiology donor studies (Retrovirus Epidemiology Donor Study and Retrovirus Epidemiology Donor Study-II) twenty years of research to advance blood product safety and availability. Transfus Med Rev 2012 26(4) 281-304. 

Nuclear power industry Increased safety and availability... 

Although in the past the main interest was to trace potentially hazardous elements, the focus was recently extended to substances, which are suspected to impact reliability, safety, and availability of the plants. Hence, the elements of environmental and technological impact have been identified as follows As, B, Cd, Cl, Hg, Mo, P, Pb, Sb, and Se [94,106]. 

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