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Probability Of Failure On Demand
Safety integrity level (SIL) is defined as the relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a safety instrumented function (SIF). The requirements for a given SIL are not consistent among all of the functional safety standards. In the functional safety standards based on the IEC 61508 standard, four SILs are defined, with SIL 4 the most dependable and SIL 1 the least. The applicable SIL is determined based on a number of quantitative factors in combination with qualitative factors such as development process and safety life cycle management. Assignment Assignment of SIL is an exercise in risk analysis where the risk associated with a specific hazard, that is intended to be protected against by a SIF, is calculated without the beneficial risk reduction effect of the SIF. That unmitigated risk is then compared against a tolerable risk target. The di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Risk
In simple terms, risk is the possibility of something bad happening. Risk involves uncertainty about the effects/implications of an activity with respect to something that humans value (such as health, well-being, wealth, property or the environment), often focusing on negative, undesirable consequences. Many different definitions have been proposed. The international standard definition of risk for common understanding in different applications is “effect of uncertainty on objectives”. The understanding of risk, the methods of assessment and management, the descriptions of risk and even the definitions of risk differ in different practice areas (business, economics, environment, finance, information technology, health, insurance, safety, security etc). This article provides links to more detailed articles on these areas. The international standard for risk management, ISO 31000, provides principles and generic guidelines on managing risks faced by organizations. Definitions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEC 61508
IEC 61508 is an international standard published by the International Electrotechnical Commission consisting of methods on how to apply, design, deploy and maintain automatic protection systems called safety-related systems. It is titled ''Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems'' (E/E/PE, or E/E/PES). IEC 61508 is a basic functional safety standard applicable to all industries. It defines functional safety as: “part of the overall safety relating to the EUC (Equipment Under Control) and the EUC control system which depends on the correct functioning of the E/E/PE safety-related systems, other technology safety-related systems and external risk reduction facilities.” The fundamental concept is that any safety-related system must work correctly or fail in a predictable (safe) way. The standard has two fundamental principles: # An engineering process called the safety life cycle is defined based on best practices in order to disc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEC 61511
IEC standard 61511 is a technical standard which sets out practices in the engineering of systems that ensure the safety of an industrial process through the use of instrumentation. Such systems are referred to as ''Safety Instrumented Systems''. The title of the standard is "''Functional safety - Safety instrumented systems for the process industry sector''". Scope The process industry sector includes many types of manufacturing processes, such as refineries, petrochemical, chemical, pharmaceutical, pulp and paper, and power. The process sector standard does not cover nuclear power facilities or nuclear reactors. IEC 61511 covers the application of electrical, electronic and programmable electronic equipment. While IEC 61511 does apply to equipment using pneumatic or hydraulic systems to manipulate final elements, the standard does not cover the design and implementation of pneumatic or hydraulic logic solvers. This standard defines the functional safety requirements establis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EN 954-1
En or EN may refer to: Businesses * Bouygues (stock symbol EN) * Esquimalt and Nanaimo Railway (reporting mark EN, but now known as Southern Railway of Vancouver Island) * Euronews, a news television and internet channel Language and writing * En or N, the 14th letter of the Roman alphabet * EN (cuneiform), the mark in Sumerian cuneiform script for a High Priest or Priestess meaning "lord" or "priest" * En (Cyrillic) (Н, н), a letter of the Cyrillic alphabet, equivalent to the Roman letter "n" * En (digraph), ‹en› used as a phoneme * En (typography), a unit of width in typography ** en dash, a dash one en long * En language, a language spoken in northern Vietnam * English language (ISO 639-1 language code en) Organisations * Eastern National, a US organization providing educational products to National Park visitors * English Nature, a former UK government conservation agency * Envirolink Northwest, an environmental organization in England Religion * En (deity) in Alb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Safety
Functional safety is the part of the overall safety of a system or piece of equipment that depends on automatic protection operating correctly in response to its inputs or failure in a predictable manner (fail-safe). The automatic protection system should be designed to properly handle likely human errors, systematic errors, hardware failures and operational/environmental stress. Objective The objective of functional safety is freedom from unacceptable risk of physical injury or of damage to the health of people either directly or indirectly (through damage to property or to the environment) by the proper implementation of one or more automatic protection functions (often called safety functions). A safety system (often called a safety-related system) consists of one or more safety functions. Functional safety is intrinsically end-to-end in scope in that it has to treat the function of a component or subsystem as part of the function of the entire automatic protection function of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEC 62061
IEC/EN 62061, ”Safety of machinery: Functional safety of electrical, electronic and programmable electronic control systems”, is the machinery specific implementation of IEC/EN 61508. It provides requirements that are applicable to the system level design of all types of machinery safety-related electrical control systems and also for the design of non-complex subsystems or devices. The risk assessment results in a risk reduction strategy which in turn, identifies the need for safety-related control functions. These functions must be documented and must include: * Functional requirements specification * Safety integrity requirements specification The functional requirements include details like frequency of operation, required response time, operating modes, duty cycles, operating environment, and fault reaction functions. The safety integrity requirements are expressed in levels called safety integrity level (SIL). Depending on the complexity of the system, some or all of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISO 26262
ISO 26262, titled "Road vehicles – Functional safety", is an international standard for functional safety of electrical and/or electronic systems that are installed in serial production road vehicles (excluding mopeds), defined by the International Organization for Standardization (ISO) in 2011, and revised in 2018. Overview of the Standard Functional safety features form an integral part of each automotive product development phase, ranging from the specification, to design, implementation, integration, verification, validation, and production release. The standard ISO 26262 is an adaptation of the Functional Safety standard IEC 61508 for Automotive Electric/Electronic Systems. ISO 26262 defines functional safety for automotive equipment applicable throughout the lifecycle of all automotive electronic and electrical safety-related systems. The first edition (ISO 26262:2011), published on 11 November 2011, was limited to electrical and/or electronic systems installed in "s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motor Industry Software Reliability Association
Motor Industry Software Reliability Association (MISRA) is an organization that produces guidelines for the software developed for electronic components used in the automotive industry.http://www.misra.org.uk The MISRA web site. It is a collaboration between vehicle manufacturers, component suppliers and engineering consultancies. In 2021, the loose consortium restructured as The MISRA Consortium Limited. Aim The aim of this organization is to provide important advice to the automotive industry for the creation and application of safe, reliable software within vehicles. The safety requirements of the software used in Automobiles is different from that of other areas such as healthcare, industrial automation, aerospace etc. The mission statement of MISRA is "To provide assistance to the automotive industry in the application and creation within vehicle systems of safe and reliable software". Formation MISRA was formed by a consortium of organizations formed in response to the UK S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALARP
ALARP ("as low as reasonably practicable"), or ALARA ("as low as reasonably achievable"), is a principle in the regulation and management of safety-critical and safety-involved systems. The principle is that the residual risk shall be reduced as far as reasonably practicable. In UK and NZ Health and Safety law, it is equivalent to SFAIRP ("so far as is reasonably practicable"). In the US, ALARA is used in the regulation of radiation risks. For a risk to be ALARP, it must be possible to demonstrate that the cost involved in reducing the risk further would be grossly disproportionate to the benefit gained. The ALARP principle arises from the fact that infinite time, effort and money could be spent in the attempt of reducing a risk to zero; not the fact that reducing the risk in half would require a finite time, effort and money. It should not be understood as simply a quantitative measure of benefit against detriment. It is more a best common practice of judgement of the balance of r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spurious Trip Level
Spurious trip level (STL) is defined as a discrete level for specifying the spurious trip requirements of safety functions to be allocated to safety systems. An STL of 1 means that this safety function has the highest level of spurious trips. The higher the STL level the lower the number of spurious trips caused by the safety system. There is no limit to the number of spurious trip levels. Safety functions and systems are installed to protect people, the environment and for asset protection. A safety function should only activate when a dangerous situation occurs. A safety function that activates without the presence of a dangerous situation (e.g., due to an internal failure) causes economic loss. The spurious trip level concept represents the probability that safety function causes a spurious (unscheduled) trip. The STL is a metric that is used to specify the performance level of a safety function in terms of the spurious trips it potentially causes. Typical safety systems that ben ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
