{"id":9254,"date":"2026-09-24T14:15:00","date_gmt":"2026-09-24T12:15:00","guid":{"rendered":"https:\/\/lorit-consultancy.com\/en\/?p=9254"},"modified":"2026-09-24T14:23:09","modified_gmt":"2026-09-24T12:23:09","slug":"what-are-we-measuring-with-metrics","status":"publish","type":"post","link":"https:\/\/lorit-consultancy.com\/en\/2026\/09\/what-are-we-measuring-with-metrics\/","title":{"rendered":"What are we measuring with metrics?"},"content":{"rendered":"<div data-layout-column=\"true\" data-column-width=\"50\" data-local-id=\"b0b957a84964\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"layoutColumn\" data-prosemirror-node-block=\"true\" data-pm-slice=\"2 2 [&quot;layoutSection&quot;,{&quot;columnRuleStyle&quot;:null,&quot;localId&quot;:&quot;2d535f569b47&quot;}]\">\n<div data-layout-content=\"true\">\n<h2 data-local-id=\"9d08933639bc\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">Understanding Safety Metrics behind IEC 61508 and ISO 26262<\/h2>\n<p data-local-id=\"9d08933639bc\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">As a consultancy we spend a fair amount of our time working with hardware metrics both for safety and reliability engineering. A few key questions crop up here:<\/p>\n<ul>\n<li data-local-id=\"55ee7085618b\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">What is the objective of hardware metrics?<\/li>\n<li data-local-id=\"a62c8bc5aac4\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\"><span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">What do the numbers tell us?<\/span><\/li>\n<li data-local-id=\"8c3e9482cc7c\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">What benefit do the metrics bring and what should we do with them?<\/li>\n<\/ul>\n<p data-local-id=\"5c2c5e591ec1\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">Two standards where we are active on a regular basis have quite different objectives for hardware metrics. In this blog we look at the strategies used both in <strong>IEC 61508<\/strong> and <strong><a href=\"https:\/\/lorit-consultancy.com\/en\/standards\/automotive\/iso26262\/\">ISO 26262<\/a><\/strong> <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">when it comes to numbers behind safety<\/span>.<\/p>\n<h2 data-local-id=\"50e3f1678fe3\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"heading\" data-prosemirror-node-block=\"true\">Objective <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">behind deriving hardware metrics <\/span><\/h2>\n<p data-local-id=\"4c03b0aa306d\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\"><span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">Utilized across different industries, hardware metrics rely on reliability<\/span> data in the form of failure in time rates (FIT) which are taken as 10E-9 failures per operational hour. In the world of IEC 61508 this usage helps yield statistics for both reliability and for safety, <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">while<\/span> in standards such ISO 26262 the focus is purely on safety.<\/p>\n<p data-local-id=\"3faf1a42a8be\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">Such metrics have different objectives and a direct comparison between IEC 61508 and ISO 26262 is not really possible as we will see below.<\/p>\n<p data-local-id=\"d99ffd26ace6\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">The main question here is <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">whether<\/span> we are looking at a repairable system and, if so, how long the system will remain unavailable following a failure.This is very much the approach of IEC 61508 and similar related standards that are focussed on availability.<\/p>\n<p data-local-id=\"d99ffd26ace6\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-9255\" src=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Industrial-controls_Hardware-metrics-blog_2609-1024x768.jpeg\" alt=\"\" width=\"720\" height=\"540\" srcset=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Industrial-controls_Hardware-metrics-blog_2609-1024x768.jpeg 1024w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Industrial-controls_Hardware-metrics-blog_2609-1920x1440.jpeg 1920w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Industrial-controls_Hardware-metrics-blog_2609-768x576.jpeg 768w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Industrial-controls_Hardware-metrics-blog_2609-1536x1152.jpeg 1536w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Industrial-controls_Hardware-metrics-blog_2609-2048x1536.jpeg 2048w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\" \/><\/p>\n<div data-layout-column=\"true\" data-column-width=\"50\" data-local-id=\"b0b957a84964\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"layoutColumn\" data-prosemirror-node-block=\"true\" data-pm-slice=\"2 2 [&quot;layoutSection&quot;,{&quot;columnRuleStyle&quot;:null,&quot;localId&quot;:&quot;2d535f569b47&quot;}]\">\n<div data-layout-content=\"true\">\n<h2 data-local-id=\"b0a57c086ad3\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"heading\" data-prosemirror-node-block=\"true\">Taking architecture into account<\/h2>\n<p data-local-id=\"d68a422e7fa4\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">In the calculations of metrics for both standards listed the architectural metric and the estimation of diagnostic coverage play a big par<span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">t &#8211; w<\/span>e are ultimately focussed on the percentage of failures that can be detected by our safety mechanisms.<\/p>\n<p data-local-id=\"d269b0803f1b\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">We multiply each FIT rate by the percentage diagnostic coverage of the safety mechanism to yield the FIT rates that are dangerous (in different categories) or safe:<\/p>\n<p data-local-id=\"d269b0803f1b\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-9257\" src=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/FIT-rate-calculations_Hardware-metrics-blog_2609.png\" alt=\"\" width=\"580\" height=\"322\" srcset=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/FIT-rate-calculations_Hardware-metrics-blog_2609.png 954w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/FIT-rate-calculations_Hardware-metrics-blog_2609-768x427.png 768w\" sizes=\"auto, (max-width: 580px) 100vw, 580px\" \/><\/p>\n<\/div>\n<div data-layout-column=\"true\" data-column-width=\"50\" data-local-id=\"b0b957a84964\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"layoutColumn\" data-prosemirror-node-block=\"true\" data-pm-slice=\"2 2 [&quot;layoutSection&quot;,{&quot;columnRuleStyle&quot;:null,&quot;localId&quot;:&quot;2d535f569b47&quot;}]\">\n<div data-layout-content=\"true\">\n<p data-local-id=\"13b5601e756c\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">In both cases the metric is similar, and provides a useful measure of the quality of the architecture.<\/p>\n<h2 data-local-id=\"605a1dd1de58\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"heading\" data-prosemirror-node-block=\"true\">What does PMHF actually tell us?<\/h2>\n<p data-local-id=\"cb9fe25334e1\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">In ISO 26262 there is a second metric &#8211; probabilistic metric for random hardware failures (PMHF). Part 10 of ISO 26262 provides a good explanation of the use of PMHF a<span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">nd clarifies that<\/span> it does not represent a failure rate. Part 5 of ISO 26262 (section 9.4.2.2) goes further to tell us that the PMHF has no absolute significance other than to enable a comparison of a new design with an existing one. This is always a difficult point with customers. People like to have a definitive statement <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">with clear<\/span> process to follow, and many customers find this point confusing.<\/p>\n<p data-local-id=\"af22042ad952\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">Our focus with the PMHF metric is to estimate the probability of violating the safety goal over the operational lifetime of the item. The result is expressed as an average probability per hour and is not a failure rate.<\/p>\n<p data-local-id=\"f32e55d2bea2\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\"><span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">The PMHF calculation in <\/span>ISO 26262 <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">provides guidance on<\/span> how to estimate the instantaneous failure rate of violating the safety goal within the vehicle lifetime. This is a simplified approach, and as we look at IEC 61508, we can see how a more comprehensive estimate can be achieved.<\/p>\n<p data-local-id=\"f32e55d2bea2\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\"><\/div><\/div><\/div><div class=\"content_section blue_bg blog_trenner_section\"><div class=\"row align-center medium-align-spaced\"><div class=\"columns border_solid_square post_thumbnail small-10 medium-5 large-3\"><div  data-ratio=\"1.3476454293629\" class=\"\"><picture><source media=\"(min-width:1024px)\" srcset=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2021\/01\/alastair-walker.webp\" width=\"722\" height=\"973\" type=\"image\/webp\" ><source media=\"(min-width:640px)\" srcset=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2021\/01\/alastair-walker.webp\" width=\"722\" height=\"973\" type=\"image\/webp\" ><img decoding=\"async\" src=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2021\/01\/alastair-walker-640x640.webp\" alt=\"Owner & Consultant\" loading=\"lazy\" width=\"640\" height=\"640\" type=\"image\/webp\" ><\/picture><svg version=\"1.1\" id=\"svg_border_solid_square\" class=\"svg_border_solid_square\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" x=\"0px\" y=\"0px\"\n\t viewBox=\"0 0 337 411.2\" style=\"enable-background:new 0 0 337 411.2;\" xml:space=\"preserve\">\n<polygon id=\"bg\" class=\"bg\" points=\"65,332.6 337,332.6 336.9,411.2 3.6,411.2 \"\/>\n<path id=\"border\" class=\"border\" d=\"M334,329.6V5.9c0-1.6-1.3-2.9-2.9-2.9l0,0L5.9,3.1C4.3,3.1,3,4.3,3,6v400.8c0,1.6,0.8,1.9,1.8,0.6\n\tl59.6-74.7l266.6-0.1C332.7,332.5,333.9,331.2,334,329.6z\"\/>\n<\/svg><\/div><div class=\"image_bottom_content\"><p>Alastair Walker, Owner \/ Consultant<\/p>\n<\/div><\/div><div class=\"columns post_content small-12 medium-6 large-7\"><div data-layout-column=\"true\" data-column-width=\"50\" data-local-id=\"b0b957a84964\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"layoutColumn\" data-prosemirror-node-block=\"true\" data-pm-slice=\"2 2 [&quot;layoutSection&quot;,{&quot;columnRuleStyle&quot;:null,&quot;localId&quot;:&quot;2d535f569b47&quot;}]\">\n<div data-layout-content=\"true\">\n<p data-local-id=\"2bd9bfa28308\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">Need help understanding which safety metrics apply to your product or how to interpret the results? Our experts can support you with functional safety analysis and compliance across IEC 61508, ISO 26262 and related standards. Contact us via the <a href=\"https:\/\/lorit-consultancy.com\/en\/contact-us\/#wpcf7-f4221-p4082-o1\" target=\"_blank\" rel=\"noopener\">form<\/a> or <a href=\"mailto:info@lorit-consultancy.com\" target=\"_blank\" rel=\"noopener\">email<\/a>.<\/p>\n<\/div>\n<\/div>\n<a class=\"add_logo_border\" target=\"_blank\" href=\"https:\/\/lorit-consultancy.com\/en\/consultancy\/\"><span>Learn more<\/span><\/a><\/div><\/div><\/div><\/div><div class=\"single_content_section single_post_section content_section\"><div class=\"row\"><div class=\"post_content columns\"><\/p>\n<div data-layout-column=\"true\" data-column-width=\"50\" data-local-id=\"b0b957a84964\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"layoutColumn\" data-prosemirror-node-block=\"true\" data-pm-slice=\"2 2 [&quot;layoutSection&quot;,{&quot;columnRuleStyle&quot;:null,&quot;localId&quot;:&quot;2d535f569b47&quot;}]\">\n<div data-layout-content=\"true\">\n<h2 data-local-id=\"2c8d1f2bf163\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"heading\" data-prosemirror-node-block=\"true\">What\u2019s dangerous and when can we detect it? PFDavg, PFH and Dangerous Failures in IEC 61508<\/h2>\n<p data-local-id=\"1065e494e7e3\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">The IEC 61508 approach <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">uses two different<\/span> quantities, depending on the demand <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">placed <\/span>on the specific safety function. <strong data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"strong\">PFDavg<\/strong> is the average probability of dangerous failure on demand <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">and is used when <\/span>low demands are placed on the safety function. <strong data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"strong\">PFH<\/strong> <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">is the <\/span>average frequency of dangerous failure <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">and is used for higher demand rates o<\/span>f the safety function or continuous operation.<\/p>\n<p data-local-id=\"5f8a24aa470d\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">The <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">resulting PFDavg or PFH value provides<\/span> an indication of the safety integrity level (SIL) that can be claimed for the product.<\/p>\n<p data-local-id=\"8e4adf5e76f3\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">IEC 61508 also divides failures into four groups: <strong data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"strong\">safe detected, safe undetected, dangerous detected and dangerous undetected<\/strong>. For this discussion, we are mainly concerned with the two dangerous failure groups.<\/p>\n<p data-local-id=\"42f66bda873f\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">A <strong data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"strong\">dangerous undetected failure<\/strong> is a failure that is not covered by our diagnostic coverage. A <strong data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"strong\">dangerous detected failure<\/strong>, <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">on the other hand, is detected by the diagnostics, but can still become a concern if there<\/span> is not sufficient time to repair the system.<\/p>\n<p data-local-id=\"cb8f1329059b\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">If the <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">demand rate <\/span>for the safety function is low (less than once a year), it is likely that a dangerous detected failure can be repaired before the next demand on the safety function. In this case, the dangerous detected failure can be disregarded from the calculation.<\/p>\n<p data-local-id=\"674ca2a3a7ae\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">The <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">complexity of the PFD calculation<\/span> depends on several factors, including the redundancy strategy (e.g. 1 out of 2, 2 out of 3), whether the device is repairable, and the relationship of common cause failures.<\/p>\n<p data-local-id=\"ac07ebc4ead9\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">The IEC 61508 approach ultimately provides a comprehensive summary of the probability of failure on demand or, <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">in the case of PFH, the <\/span>average frequency of dangerous failure.<\/p>\n<p data-local-id=\"ac07ebc4ead9\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-9265 aligncenter\" src=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img2_Hardware-metrics-blog_2609-1024x352.png\" alt=\"\" width=\"720\" height=\"248\" srcset=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img2_Hardware-metrics-blog_2609-1024x352.png 1024w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img2_Hardware-metrics-blog_2609-1920x661.png 1920w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img2_Hardware-metrics-blog_2609-768x264.png 768w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img2_Hardware-metrics-blog_2609-1536x529.png 1536w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img2_Hardware-metrics-blog_2609-2048x705.png 2048w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\" \/><\/p>\n<p data-local-id=\"ac07ebc4ead9\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-9267\" src=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img3_Hardware-metrics-blog_2609-1024x122.png\" alt=\"\" width=\"600\" height=\"71\" srcset=\"https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img3_Hardware-metrics-blog_2609-1024x122.png 1024w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img3_Hardware-metrics-blog_2609-768x91.png 768w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img3_Hardware-metrics-blog_2609-1536x183.png 1536w, https:\/\/lorit-consultancy.com\/wp-content\/uploads\/2026\/09\/Img3_Hardware-metrics-blog_2609.png 1612w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><\/p>\n<div data-layout-column=\"true\" data-column-width=\"50\" data-local-id=\"b0b957a84964\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"layoutColumn\" data-prosemirror-node-block=\"true\" data-pm-slice=\"2 2 [&quot;layoutSection&quot;,{&quot;columnRuleStyle&quot;:null,&quot;localId&quot;:&quot;2d535f569b47&quot;}]\">\n<div data-layout-content=\"true\">\n<h2 data-local-id=\"a399f521479c\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"heading\" data-prosemirror-node-block=\"true\">Conclusion<\/h2>\n<p data-local-id=\"219941dbd474\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">Whichever measures we use as a yardstick for the quality of our system, and more specifically the hardware, we need to be clear <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">about the context and what we a<\/span>re trying to estimate. <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">Whether<\/span> the device is repairable or not is one key question (and not a consideration for ISO 26262). <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">The quality of the <\/span>diagnostics in the architecture is another key point.<\/p>\n<p data-local-id=\"40ba185891e0\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">Ultimately, the more complex the system, the higher the failure rate will be. <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">However, the level of diagnostic coverage also needs to be considered when determining whether the resulting metric is acceptable.<\/span><\/p>\n<p data-local-id=\"0d6a5c5ff369\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">We do not have apples-to-apples comparisons across industries and standards. Ultimately, architectural metrics provide useful data on the quality of the design, while PFD or PFH gives us a comprehensive figure <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">for failure <\/span>in IEC 61508. ISO 26262 PMHF provides more of a benchmark for comparing different items and is less useful for defining a quantitative figure for <span class=\"fabric-background-color-mark\" data-background-custom-color=\"#fedec8\" data-prosemirror-content-type=\"mark\" data-prosemirror-mark-name=\"backgroundColor\">the overall failure rate.<\/span><\/p>\n<p data-local-id=\"c89c0d3bb619\" data-prosemirror-content-type=\"node\" data-prosemirror-node-name=\"paragraph\" data-prosemirror-node-block=\"true\">By <a href=\"https:\/\/lorit-consultancy.com\/en\/about-us\/#alastair-walker\" target=\"_blank\" rel=\"noopener\">Alastair Walker<\/a>, Owner \/ Consultant<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Understanding Safety Metrics behind IEC 61508 and ISO 26262 As a consultancy we spend a fair amount of our time working with hardware metrics both for safety and reliability engineering. A few key questions crop up here: What is the objective of hardware metrics? What do the numbers tell us? What benefit do the metrics [&hellip;]<\/p>\n","protected":false},"author":11,"featured_media":9262,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[90,91,93],"tags":[],"class_list":["post-9254","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-reliability","category-safety","category-automotive"],"acf":[],"_links":{"self":[{"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/posts\/9254","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/comments?post=9254"}],"version-history":[{"count":6,"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/posts\/9254\/revisions"}],"predecessor-version":[{"id":9272,"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/posts\/9254\/revisions\/9272"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/media\/9262"}],"wp:attachment":[{"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/media?parent=9254"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/categories?post=9254"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lorit-consultancy.com\/en\/wp-json\/wp\/v2\/tags?post=9254"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}