{"id":50167,"date":"2025-11-03T14:57:33","date_gmt":"2025-11-03T13:57:33","guid":{"rendered":"https:\/\/www.gt-engineering.it\/?post_type=pubblicazione&p=50167"},"modified":"2026-02-09T13:01:15","modified_gmt":"2026-02-09T12:01:15","slug":"p1-reliability-data-for-components-used-in-safety-systems","status":"publish","type":"pubblicazione","link":"https:\/\/www.gt-engineering.it\/en\/pubblications\/in-depth-articles-tuttomisure\/p1-reliability-data-for-components-used-in-safety-systems\/","title":{"rendered":"P1: Reliability data for components used in safety systems"},"content":{"rendered":"\n\n \n \n \n
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THE QUESTION:\u00a0<\/span><\/strong>\u00a0What are the main\u00a0<\/span>reliability data<\/span><\/strong>\u00a0for components used in Security Systems?<\/span><\/p>\n

When it comes to components used in safety systems, you’re familiar with the concept of\u00a0<\/span>failure rate<\/span><\/strong>\u00a0. There are actually two other important metrics to know:\u00a0<\/span>MTTF (Mean Time to Failure)<\/span><\/strong>\u00a0and\u00a0<\/span>B10 . The\u00a0<\/span>latter<\/span><\/sub><\/strong>\u00a0is important when dealing with the\u00a0<\/span>reliability of electromechanical components<\/span><\/strong>\u00a0. In this article, we’ll explain all three metrics and how they’re related.<\/span><\/p>\n

If you need the reliability values of a pressure transmitter for use in a safety system, you’ll likely look in the component safety manual and, in particular, look for the different types of failure rates. These are typically calculated by specialized laboratories such as\u00a0<\/span>Exida<\/span><\/strong><\/a><\/em>\u00a0or one of the\u00a0<\/span>T\u00dcV<\/span><\/strong><\/a><\/em>\u00a0companies .<\/span><\/p>\n

The situation is different when you need the reliability parameters of a pneumatic solenoid valve; in this case, you should contact the manufacturer directly and rely on the\u00a0<\/span>B\u00a0<\/span>10D<\/span><\/sub><\/strong>\u00a0value provided.<\/span><\/p>\n

Questions that may arise are: “Why is there a different approach in the two cases? Why does\u00a0the data for\u00a0<\/span>electronic components depend only on the component itself, while for an\u00a0<\/span><\/strong>electromechanical<\/span><\/strong>\u00a0component it depends not only on the component but also on how the component is connected to the logic solver? Why is it possible to know all types of failure rates for an electronic component, while for the solenoid valve only a\u00a0<\/span>B\u00a0<\/span>10D<\/span><\/sub><\/strong>\u00a0value ? How can we use these values?”<\/span><\/p>\n

It will take several articles to answer all these questions. In this one, we will focus on explaining the three parameters:\u00a0failure\u00a0<\/span>rate<\/span><\/strong>\u00a0,\u00a0<\/span>mean time to failure<\/span><\/strong>\u00a0, and\u00a0<\/span>B10\u00a0<\/span>.<\/span><\/sub><\/strong><\/p>\n<\/div> <\/div>\n \n \n

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When dealing with the reliability of a component used in a safety system the main parameter is the Failure Rate \u03bb: its unit of measurement is the inverse of time. It is common practice to use the unit of measurement “failures per billion (10\u00a0<\/span>9<\/span><\/sup>\u00a0) hours”, this unit is known as\u00a0<\/span>FIT\u00a0<\/span><\/strong>(Failures In Time)<\/span><\/strong>\u00a0. For example, a particular integrated circuit that suffers seven failures per billion hours of operation at 25\u00b0C, has a failure rate of 7 FIT.<\/span><\/p>\n

According to IEC\u00a0<\/span>61508<\/span><\/strong><\/a>\u00a0,<\/span><\/em>\u00a0there are four types of faults:<\/span><\/p>\n