{"id":3796,"date":"2023-01-04T17:51:06","date_gmt":"2023-01-04T16:51:06","guid":{"rendered":"https:\/\/www.gt-engineering.it\/normative-tecniche\/%tipologia_normativa%\/iec-61511-gt-engineering\/"},"modified":"2026-08-29T18:24:17","modified_gmt":"2026-08-29T17:24:17","slug":"iec-61511-gt-engineering","status":"publish","type":"normativa_tecnica","link":"https:\/\/www.gt-engineering.it\/en\/technical-standards\/en-iec-standards\/iec-61511-gt-engineering\/","title":{"rendered":"IEC 61511: Safety instrumented systems for the process industry"},"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                \n\n    \n        \n            \n                \n                    <picture\n                        class=\"\"\n                                            >\n                                                                                                        <source\n                                media=\"(max-width: 150px)\"\n                                width=\"150\"\n                                height=\"150\"\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/cover-2-150x150.jpg.webp\"\n                                type=\"image\/webp\"\n                            \/>\n                                                                                <source\n                                media=\"(max-width: 236px)\"\n                                width=\"236\"\n                                height=\"300\"\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/cover-2-236x300.jpg.webp\"\n                                type=\"image\/webp\"\n                            \/>\n                                                                                <source\n                                media=\"(max-width: 699px)\"\n                                width=\"699\"\n                                height=\"890\"\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/cover-2.jpg.webp\"\n                                type=\"image\/webp\"\n                            \/>\n                                                                                <source\n                                media=\"(max-width: 699px)\"\n                                width=\"699\"\n                                height=\"890\"\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/cover-2.jpg.webp\"\n                                type=\"image\/webp\"\n                            \/>\n                                                                            <img\n                            class=\"a-image transparent border-image h-auto  w-full\"\n                                                        srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/cover-2.jpg.webp\"\n                                                        width=\"699\"\n                            height=\"890\"\n                                                                                    title=\"cover\"\n                                                        type=\"image\/webp\"\n                            loading=\"eager\" fetchpriority=\"high\" decoding=\"async\"                        \/>\n                    <\/picture>\n\n                \n\n                    \n    \n\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 style=\"text-align: justify;\"><span style=\"text-align: justify;\">IEC 61511 (all parts) is intended as the process industry sector implementation of <strong><a href=\"https:\/\/www.gt-engineering.it\/en\/technical-standards\/en-iec-standards\/iec-61508\/\">IEC 61508<\/a><\/strong>; it addresses the application of SISs (Safety Instrumented System) in the process industry. <\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"text-align: justify;\"><strong>Safety Instrumented Functions (SIF) <\/strong>are protective functions implemented in a <strong>Safety Instrumented System (SIS)<\/strong>. A typical SIS is comprised of multiple SIFs; typically, each SIF has process sensors that measure a process deviation, a logic solver that executes the functional logic, and final control elements (e.g. valves)\u00a0that bring the process to a safe state. The IEC 61511 series of standards addresses SIS based on the use of <strong>electrical, electronic, or programmable electronic technology in the process industry sector<\/strong>. IEC 61511 series also address a process Hazard and Risk Assessment (H&amp;RA) from which the specification for SISs are derived.<\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"text-align: justify;\">The standard recognises that <strong>systematic failures<\/strong> come from <strong>human errors<\/strong> and they can be reduced with the implementation of solid organisational processes.<\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"text-align: justify;\">The first edition of the standard was issued in 2003. The second edition was published in 2016. The standard has four parts:<\/span><\/p>\n<ul style=\"list-style-type: square;\">\n<li style=\"margin: 0cm 0cm 0cm 36pt; text-align: justify;\"><span style=\"text-align: justify;\"><strong>Part 1<\/strong> \u2013 It is the only normative part of the series. It includes terminology, and requirements for specification, hardware design and application programming, commissioning, validation, operation, maintenance and testing of SIS components.<\/span><\/li>\n<li style=\"margin: 0cm 0cm 0cm 36pt; text-align: justify;\"><span style=\"text-align: justify;\"><strong>Part 2 <\/strong>\u2013 It is an Informative guidance on Part 1. It contains Annex A, that provides guidance and implementation examples of requirements outlined in Part 1.<\/span><\/li>\n<li style=\"margin: 0cm 0cm 0cm 36pt; text-align: justify;\"><span style=\"text-align: justify;\"><strong>Part 3<\/strong> &#8211; \u00a0It is an informative part of the series that provides information on available methods to conduct Hazard and Risk Assessment (H&amp;RA) to determine integrity requirements, i.e. Safety Integrity Level (SIL).<\/span><\/li>\n<li style=\"margin: 0cm 0cm 8pt 36pt; text-align: justify;\"><span style=\"text-align: justify;\"><strong>Part 4 <\/strong>\u2013 It is actually a Technical Report. It contains explanation and rationale for changes from Edition 1 to Edition 2.<\/span><\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><span style=\"text-align: justify;\">Compliance with the IEC\u00a061511 standard series will help assure reliable and effective implementation of SIS to achieve risk reduction objectives and thereby improving process safety. <\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"text-align: justify;\">IEC 61511 is recognized as a good engineering practice in most countries and a regulatory requirement in an increasing number of countries. End users in the process industry should use this standard series to develop their internal procedures, work processes, and management systems. Implementing a <strong>SIS Safety life cycle<\/strong> provides a framework for managing people, processes, and systems to <strong>improve overall safety and operational performance<\/strong>.<\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"text-align: justify;\">The standard applies when devices that meet the requirements of <strong><a href=\"https:\/\/www.gt-engineering.it\/en\/technical-standards\/en-iec-standards\/iec-61508\/\">IEC 61508<\/a><\/strong> series are integrated into an overall safety-related control system, <strong>to be used in a process sector application<\/strong>. It does not apply to manufacturers wishing to claim that their devices are suitable for use in SISs for the process sector; for this purpose, IEC 61508-2 and IEC 61508-3 have to be used. <\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"text-align: justify;\">The normative part does not contain any formula. The reason is that the spirit of IEC 61511-1 is to <strong>define what has to be achieved and not how to achieve it<\/strong>. <\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"text-align: justify;\">Moreover, <strong>for the random part of the SIS<\/strong>, the standard is following the requirements of IEC 61508 series. That means the formulas for the calculation of the PFD and PFH are the ones in the IEC 61508-6. <strong>For the architectural contraints<\/strong>, you need to follow the requirements of IEC 61508-1 and -2.\u00a0\u00a0<\/span><\/p>\n<p>IEC 61511-1 takes inspiration from the IEC 61508 concepts of <strong>Management of functional safety<\/strong> and of the <strong>Overall safety life cycle requirements<\/strong> and develops around the concept of the<strong> SIS safety life cycle phases and FSA stages<\/strong>.<\/p>\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>IEC 61511 (all parts) is intended as the process industry sector implementation of IEC 61508; it addresses the application of SISs (Safety Instrumented System) &#8230;<\/p>\n","protected":false},"author":1,"featured_media":3507,"parent":0,"menu_order":29,"template":"","meta":{"_acf_changed":false,"footnotes":""},"normative-tecniche":[58],"class_list":["post-3796","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 v27.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>IEC 61511: Safety instrumented systems for the process industry<\/title>\n<meta name=\"description\" content=\"IEC 61511 (all parts) is intended as the process industry sector implementation of IEC 61508; 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