{"id":3817,"date":"2023-01-04T17:57:14","date_gmt":"2023-01-04T16:57:14","guid":{"rendered":"https:\/\/www.gt-engineering.it\/normative-tecniche\/%tipologia_normativa%\/why-iec-61508-was-written\/"},"modified":"2023-06-26T08:27:52","modified_gmt":"2023-06-26T07:27:52","slug":"why-iec-61508-was-written","status":"publish","type":"normativa_tecnica","link":"https:\/\/www.gt-engineering.it\/en\/technical-standards\/en-iec-standards\/iec-61508\/why-iec-61508-was-written\/","title":{"rendered":"Why IEC 61508 was written"},"content":{"rendered":"\n\n    \n        <section\n            data-name=\"Contenuto testuale con immagine\"\n            class=\"bow-gte-testo-media u-spacer-base\"\n            id=\"\"\n        >\n            \n<div class=\"o-text-media px-side-spacer sm:px-side-spacer-sm lg:px-side-spacer-tablet 2xl:px-side-spacer-desktop flex flex-wrap items-start md:block\">\n\n    \n        \n                    <div\n                class=\"h-auto mb-6 md:mb-4 lg:mb-8 xl:mb-9 float-left mr-6 md:mr-4 lg:mr-8 xl:mr-9  overflow-hidden shadow-content-image w-full md:w-1\/3\"\n            >\n                \r\n\r\n    \r\n        \r\n            \r\n                \r\n                    <picture\r\n                        class=\"\"\r\n                                            >\r\n                                                                                                        <source\r\n                                media=\"(max-width: 150px)\"\r\n                                width=\"150\"\r\n                                height=\"150\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/8-why-150x150.jpg.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 300px)\"\r\n                                width=\"300\"\r\n                                height=\"224\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/8-why-300x224.jpg.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 768px)\"\r\n                                width=\"768\"\r\n                                height=\"572\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/8-why-768x572.jpg.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 958px)\"\r\n                                width=\"958\"\r\n                                height=\"714\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/8-why.jpg.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                            <img\r\n                            class=\"a-image transparent border-image h-auto  w-full\"\r\n                                                        srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/8-why.jpg.webp\"\r\n                                                        title=\"8 why\"\r\n                                                        type=\"image\/webp\"\r\n                        \/>\r\n                    <\/picture>\r\n\r\n                \r\n\r\n                    \r\n    \r\n            <\/div>\n        \n                    <div class=\"relative w-full\">\n                \n<div class=\"a-text font-text text-base normal mt-8 first:mt-0 space-y-4\">\n    <p>Back in the &lsquo;90&rsquo;s, Safety functions were more and more carried out by electronic or programmable electronic systems. These systems are usually complex, making it impossible, in practice, to fully determine every failure mode or to test all possible behaviours.<\/p>\n<p>The challenge was to design the system in such a way as to prevent dangerous failures or to control them when they arise. Dangerous failures may arise from:<\/p>\n<ul>\n<li style=\"list-style-type:none\">\n<ul>\n<li style=\"list-style-type:none\">\n<ul style=\"list-style-type:square\">\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Incorrect specifications of the safety-related control system.<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Omissions in the safety requirements specification (e.g. failure to develop all relevant safety functions during different modes of operation).<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Random hardware failure mechanisms.<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Systematic hardware failure mechanisms.<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Software errors;<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Common cause failures;<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Human error;<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 8pt 36pt\">Environmental influences (e.g. electromagnetic, temperature, mechanical phenomena);<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>IEC 61508 contains requirements to minimise these failures and build a <strong>reliable safety-related control system<\/strong>. Its aim was:<\/p>\n<ul style=\"list-style-type:square\">\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Release the potential of E\/E\/PE technology to improve machinery and process safety.<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Enable technological developments to take place within an overall safety framework.<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Provide a technically sound, system based approach, with sufficient flexibility for the future.<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Provide a risk-based approach for determining the required performance of safety-related control systems.<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 0cm 36pt\">Provide a generically-based standard that can be used directly by industry but can also help with developing sector standards (e.g. machinery, process chemical plants, medical or rail) or product standards (e.g. power drive systems);<\/li>\n<li style=\"margin-top:0cm; margin-right:0cm; margin-bottom:0cm; text-align:justify; margin:0cm 0cm 8pt 36pt\">Provide a means for users and regulators to gain confidence when using computer-based technology.<\/li>\n<\/ul>\n<\/div>            <\/div>\n        \n        \n                <div class=\"clear-both\"><\/div>\n        \n\n    <\/div>\n        <\/section>\n\n    \n","protected":false},"excerpt":{"rendered":"<p>Back in the &lsquo;90&rsquo;s, Safety functions were more and more carried out by electronic or programmable electronic systems. These systems are usually compl&#8230;<\/p>\n","protected":false},"author":1,"featured_media":36248,"parent":3866,"menu_order":6,"template":"","meta":{"_acf_changed":false,"footnotes":""},"normative-tecniche":[58],"class_list":["post-3817","normativa_tecnica","type-normativa_tecnica","status-publish","has-post-thumbnail","hentry","tipologia_normativa-en-iec-standards"],"acf":{"sottotitolo":"","allegati":null},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.2 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Why IEC 61508 was written<\/title>\n<meta name=\"description\" content=\"Back in the \u201890\u2019s, Safety functions were more and more carried out by electronic or programmable electronic systems. 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