Safety Integrity level    Probability of Failure on Demand    Risk Reduction Factor
SIL 4                                  10-5≥ PofD <10-4                                     100,000 to 10,000
SIL 3                                  10-4≥ PofD <10-3                                     10,000 to 1,000
SIL 2                                  10-3≥ PofD < 10-2                                    1,000 to 100
SIL 1                                  10-2≥ PofD < 10-1                                    100 to 10

 

LV: kā mēs saprotam SIL un drošību:

• aizsardzības mehānismi, kas samazina risku, bīstama un/vai nenoteikta stāvokļa varbutību

• zemā bīstamā un/vai nenoteiktā stāvokļa varbutība neļauj mērīto objektu klasificēt kā drošu

• drošu objektu raksturo ekspluatācijas stāvoklis, droša atteice un aizsardzības atteice (kontrolēta atteice), kā arī noteikts bīstamā/nedrošā stāvokļa laiks, un tam ir skaidri definētas īpašības, kas atspoguļotas konstrukcijā

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LT: Kaip mes suprantame SIL ir saugumą:

• apsauginiai mechanizmai, mažinantys riziką, pavojingos ir/ar neapibrėžtos būklės tikimybę

• maža pavojingos ir (arba) neapibrėžtos būsenos tikimybė neleidžia skaičiuojamo objekto priskirti saugiam

• saugiam objektui būdinga eksploatacinė būsena, saugus gedimas ir apsauginis gedimas (valdomas gedimas), taip pat nustatytas pavojingos/neapibrėžtos būklės laikas ir turi aiškiai apibrėžtas charakteristikas, atsispindinčias konstrukcijoje.

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EN: as we understand SIL & Safety: 

• protective mechanisms that reduce risk, the likelihood of a dangerous and/or uncertain condition

• the low probability of a dangerous and/or uncertain state does not allow the metered object to be classified as safe

• a safe object is characterized by an operational state, a safe failure and/a protective failure (controlled failure), as well as a defined time of a dangerous/uncertain state and has clearly defined characteristics reflected in the structure

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RU: rак мы понимаем SIL и безопасность:

• защитные механизмы, которые уменьшают риск, вероятность опасного и/или неопределенного состояния 

• малая вероятность опасного и/или неопределенного состояния не позволяет относить метрированный объект к безопасным

• безопасный объект характеризуется работоспособным состояние  безопасным отказом и защитным отказом (управляемый отказ), а также деффинированным временем опасного/неопределенного состяния и имеет четко выраженные признаки отраженные в структуре

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EN 50126 - considers RAMS, understood as reliability, availability, maintainability and safety and their interaction; - considers the generic aspects of the RAMS life cycle. The guidance in this part can still be used in the application of specific standards; - defines: - a process, based on the system life cycle and tasks within it, for managing RAMS; - a systematic process, tailorable to the type and size of the system under consideration, for specifying requirements for RAMS and demonstrating that these requirements are achieved; - addresses railway specifics; - enables conflicts between RAMS elements to be controlled and managed effectively; - does not define: - RAMS targets, quantities, requirements or solutions for specific railway applications; - rules or processes about the certification of railway products against the requirements of this standard; - an approval process for the railway stakeholders. This part 1 of EN 50126 applies to railway application fields, namely Command, Control and Signalling, Rolling Stock and Fixed Installations, and specifically: - to the specification and demonstration of RAMS for all railway applications and at all levels of such an application, as appropriate, from complete railway systems to major systems and to individual and combined subsystems and components within these major systems, including those containing software; in particular: - to new systems; - to new systems integrated into existing systems already accepted, but only to the extent and insofar as the new system with the new functionality is being integrated. It is otherwise not applicable to any unmodified aspects of the existing system; - as far as reasonably practicable, to modifications and extensions of existing systems already accepted, but only to the extent and insofar as existing systems are being modified. It is otherwise not applicable to any unmodified aspect of the existing system; - at all relevant phases of the life cycle of an application; - for use by railway duty holders and the railway suppliers. It is not required to apply this standard to existing systems that remain unmodified, including those systems already compliant with any former version of EN 50126. The process defined by this European Standard assumes that railway duty holders and railway suppliers have business-level policies addressing Quality, Performance, and Safety. The approach defined in this standard is consistent with the application of quality management requirements contained within EN ISO 9001.