{"id":3,"date":"2025-10-31T00:25:51","date_gmt":"2025-10-31T00:25:51","guid":{"rendered":"https:\/\/vibromera.eu\/glossary\/iso-10816-3\/"},"modified":"2026-06-08T04:12:49","modified_gmt":"2026-06-08T04:12:49","slug":"iso-10816-3","status":"publish","type":"glossary","link":"https:\/\/vibromera.eu\/nb\/glossary\/iso-10816-3\/","title":{"rendered":"ISO 10816-3: Vibrasjonsgrenser for industrimaskiner"},"content":{"rendered":"
\n\n\n \n \n ISO 10816-3: Vibration Limits for Industrial Machines<\/title>\n <meta name=\"description\" content=\"An overview of ISO 10816-3, the specific standard providing vibration severity limits and evaluation zones for common industrial machines like pumps, motors, and fans.\">\n <meta name=\"robots\" content=\"index, follow\">\n \n \n <!-- Open Graph -->\n <meta property=\"og:title\" content=\"ISO 10816-3: Vibration Limits for Industrial Machines\">\n <meta property=\"og:description\" content=\"An overview of ISO 10816-3, the specific standard providing vibration severity limits and evaluation zones for common industrial machines like pumps, motors, and fans.\">\n <meta property=\"og:url\" content=\"https:\/\/vibromera.eu\/glossary\/iso-10816-3\/\">\n <meta property=\"og:type\" content=\"article\">\n \n <!-- Twitter Cards -->\n <meta name=\"twitter:card\" content=\"summary\">\n <meta name=\"twitter:title\" content=\"ISO 10816-3: Vibration Limits for Industrial Machines\">\n <meta name=\"twitter:description\" content=\"An overview of ISO 10816-3, the specific standard providing vibration severity limits and evaluation zones for common industrial machines like pumps, motors, and fans.\">\n \n <!-- Schema.org TechArticle -->\n <script type=\"application\/ld+json\">\n {\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"TechArticle\",\n \"headline\": \"ISO 10816-3: Mechanical vibration - Evaluation of machine vibration by measurements on non-rotating parts - Part 3: Industrial machines\",\n \"description\": \"Standard providing vibration severity limits and evaluation zones for common industrial machines like pumps, motors, and fans\",\n \"url\": \"https:\/\/vibromera.eu\/glossary\/iso-10816-3\/\",\n \"about\": {\n \"@type\": \"Thing\",\n \"name\": \"ISO 10816-3 Standard\"\n }\n }\n <\/script>\n \n <!-- Schema.org BreadcrumbList -->\n <script type=\"application\/ld+json\">\n {\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"BreadcrumbList\",\n \"itemListElement\": [\n {\n \"@type\": \"ListItem\",\n \"position\": 1,\n \"name\": \"Home\",\n \"item\": \"https:\/\/vibromera.eu\/\"\n },\n {\n \"@type\": \"ListItem\",\n \"position\": 2,\n \"name\": \"Glossary\",\n \"item\": \"https:\/\/vibromera.eu\/glossary\/\"\n },\n {\n \"@type\": \"ListItem\",\n \"position\": 3,\n \"name\": \"ISO Standards\",\n \"item\": \"https:\/\/vibromera.eu\/glossary\/#iso-standards\"\n },\n {\n \"@type\": \"ListItem\",\n \"position\": 4,\n \"name\": \"ISO 10816-3\",\n \"item\": \"https:\/\/vibromera.eu\/glossary\/iso-10816-3\/\"\n }\n ]\n }\n <\/script>\n\n <!-- Schema.org FAQPage -->\n <script type=\"application\/ld+json\">\n {\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"FAQPage\",\n \"mainEntity\": [\n {\n \"@type\": \"Question\",\n \"name\": \"What vibration level is acceptable for a pump according to ISO 10816-3?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"For a typical medium-sized pump (15-300 kW) on a rigid foundation (Group 2), vibration up to 1.12 mm\/s RMS is excellent (Zone A), up to 2.8 mm\/s is acceptable (Zone B), up to 7.1 mm\/s requires investigation (Zone C), and above 7.1 mm\/s means immediate shutdown is recommended (Zone D).\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"What is the difference between rigid and flexible foundations in ISO 10816-3?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"A rigid foundation (concrete pad, structural steel) transmits vibration directly and requires lower vibration limits. A flexible foundation (spring isolators, rubber mounts) allows higher vibration at the machine because it isolates the structure, so the standard permits higher vibration limits for flexibly mounted machines.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"Has ISO 10816-3 been replaced?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Yes, ISO 10816-3 has been formally superseded by ISO 20816-3. However, the core zone boundary values remain highly relevant and are still widely used in industry. Many existing monitoring systems and maintenance programs continue to reference ISO 10816-3 limits.\"\n }\n }\n ]\n }\n <\/script>\n\n <link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n <link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n <link href=\"https:\/\/fonts.googleapis.com\/css2?family=DM+Sans:ital,wght@0,400;0,500;0,600;0,700;1,400&family=Playfair+Display:wght@700;800&display=swap\" rel=\"stylesheet\">\n \n <style>\n :root {\n --blue-900: #0d2137;\n --blue-800: #0f3460;\n --blue-700: #16498a;\n --blue-600: #1a5fac;\n --blue-500: #1976D2;\n --blue-400: #42a5f5;\n --blue-300: #90caf9;\n --blue-200: #bbdefb;\n --blue-100: #e3f2fd;\n --blue-50: #f0f7ff;\n \n --beige-100: #faf6f0;\n --beige-200: #f5edd8;\n --beige-300: #e8dcc8;\n --beige-400: #d4c5a9;\n \n --white: #ffffff;\n --gray-50: #fafafa;\n --gray-100: #f5f5f5;\n --gray-200: #eeeeee;\n --gray-300: #e0e0e0;\n --gray-500: #9e9e9e;\n --gray-600: #757575;\n --gray-700: #616161;\n --gray-800: #424242;\n --gray-900: #212121;\n\n --zone-a: #2e7d32;\n --zone-a-bg: #e8f5e9;\n --zone-a-light: #a5d6a7;\n --zone-b: #f9a825;\n --zone-b-bg: #fffde7;\n --zone-b-light: #fff59d;\n --zone-c: #ef6c00;\n --zone-c-bg: #fff3e0;\n --zone-c-light: #ffcc80;\n --zone-d: #c62828;\n --zone-d-bg: #ffebee;\n --zone-d-light: #ef9a9a;\n \n --radius-sm: 6px;\n --radius-md: 10px;\n --radius-lg: 16px;\n --radius-xl: 24px;\n \n --shadow-sm: 0 1px 3px rgba(0,0,0,.08);\n --shadow-md: 0 4px 12px rgba(0,0,0,.1);\n --shadow-lg: 0 8px 30px rgba(0,0,0,.12);\n --shadow-xl: 0 20px 60px rgba(0,0,0,.15);\n }\n\n * { margin: 0; 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}\n .hero-breadcrumb span { margin: 0 6px; }\n .hero h1 {\n font-family: 'Playfair Display', serif;\n font-size: clamp(26px, 4vw, 40px);\n font-weight: 800;\n line-height: 1.2;\n margin-bottom: 16px;\n letter-spacing: -0.5px;\n }\n .hero-subtitle {\n font-size: 17px;\n opacity: .85;\n max-width: 700px;\n line-height: 1.6;\n }\n .hero-badge {\n display: inline-block;\n background: rgba(255,255,255,.15);\n backdrop-filter: blur(8px);\n border: 1px solid rgba(255,255,255,.2);\n padding: 6px 14px;\n border-radius: 20px;\n font-size: 12px;\n font-weight: 600;\n letter-spacing: .5px;\n text-transform: uppercase;\n margin-bottom: 16px;\n }\n\n \/* \u2500\u2500\u2500 NAV ANCHORS \u2500\u2500\u2500 *\/\n .quick-nav {\n background: var(--white);\n border-bottom: 1px solid var(--gray-200);\n padding: 0 24px;\n position: sticky;\n top: 0;\n z-index: 100;\n box-shadow: var(--shadow-sm);\n }\n .quick-nav-inner {\n max-width: 960px;\n margin: 0 auto;\n display: flex;\n gap: 0;\n overflow-x: auto;\n scrollbar-width: none;\n }\n .quick-nav-inner::-webkit-scrollbar { display: none; }\n .quick-nav a {\n display: block;\n padding: 14px 18px;\n font-size: 13px;\n font-weight: 600;\n color: var(--gray-600);\n text-decoration: none;\n white-space: nowrap;\n border-bottom: 2px solid transparent;\n transition: all .2s;\n }\n .quick-nav a:hover,\n .quick-nav a.active {\n color: var(--blue-600);\n border-bottom-color: var(--blue-500);\n }\n\n \/* \u2500\u2500\u2500 LAYOUT \u2500\u2500\u2500 *\/\n .container {\n max-width: 960px;\n margin: 0 auto;\n padding: 0 24px;\n }\n .section {\n padding: 48px 0;\n }\n .section + .section {\n border-top: 1px solid var(--gray-200);\n }\n .section-alt {\n background: var(--beige-100);\n }\n .section-blue {\n background: var(--blue-50);\n }\n\n \/* \u2500\u2500\u2500 SUMMARY SHORTS \u2500\u2500\u2500 *\/\n .shorts-grid {\n display: grid;\n grid-template-columns: 1fr;\n gap: 24px;\n margin-top: 32px;\n }\n\n \/* \u2500\u2500\u2500 MAIN TABLE \u2500\u2500\u2500 *\/\n .limits-table-wrap {\n background: var(--white);\n border-radius: var(--radius-lg);\n box-shadow: var(--shadow-lg);\n overflow: hidden;\n border: 1px solid var(--blue-200);\n }\n .limits-table-header {\n background: linear-gradient(135deg, var(--blue-800), var(--blue-600));\n color: var(--white);\n padding: 20px 24px;\n }\n .limits-table-header h2 {\n font-family: 'Playfair Display', serif;\n font-size: 20px;\n font-weight: 700;\n margin-bottom: 4px;\n }\n .limits-table-header p {\n font-size: 13px;\n opacity: .8;\n }\n .limits-table {\n width: 100%;\n border-collapse: collapse;\n font-size: 14px;\n }\n .limits-table thead th {\n background: var(--blue-900);\n color: var(--white);\n padding: 12px 16px;\n text-align: center;\n font-weight: 600;\n font-size: 13px;\n letter-spacing: .3px;\n }\n .limits-table thead th:first-child {\n text-align: left;\n }\n .limits-table tbody td {\n padding: 14px 16px;\n text-align: center;\n border-bottom: 1px solid var(--gray-200);\n }\n .limits-table tbody td:first-child {\n text-align: left;\n font-weight: 600;\n }\n .limits-table tbody tr:last-child td {\n border-bottom: none;\n }\n .limits-table tbody tr:hover {\n background: var(--blue-50);\n }\n .limits-table .zone-val {\n display: inline-block;\n padding: 4px 12px;\n border-radius: 6px;\n font-weight: 700;\n font-size: 15px;\n min-width: 60px;\n }\n .zone-a-val { background: var(--zone-a-bg); color: var(--zone-a); }\n .zone-b-val { background: var(--zone-b-bg); color: var(--zone-b); }\n .zone-c-val { background: var(--zone-c-bg); color: var(--zone-c); }\n .zone-d-val { background: var(--zone-d-bg); color: var(--zone-d); }\n\n .group-tag {\n font-size: 11px;\n color: var(--gray-600);\n font-weight: 400;\n display: block;\n margin-top: 2px;\n }\n .most-common {\n background: var(--blue-100);\n border-left: 3px solid var(--blue-500);\n }\n\n \/* \u2500\u2500\u2500 ZONE LEGEND \u2500\u2500\u2500 *\/\n .zone-legend {\n display: grid;\n grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));\n gap: 12px;\n margin-top: 20px;\n padding: 0 24px 24px;\n }\n .zone-card {\n border-radius: var(--radius-md);\n padding: 14px 16px;\n display: flex;\n align-items: flex-start;\n gap: 12px;\n }\n .zone-card-a { background: var(--zone-a-bg); border-left: 4px solid var(--zone-a); }\n .zone-card-b { background: var(--zone-b-bg); border-left: 4px solid var(--zone-b); }\n .zone-card-c { background: var(--zone-c-bg); border-left: 4px solid var(--zone-c); }\n .zone-card-d { background: var(--zone-d-bg); border-left: 4px solid var(--zone-d); }\n .zone-card strong {\n font-size: 15px;\n display: block;\n margin-bottom: 2px;\n }\n .zone-card p {\n font-size: 12px;\n color: var(--gray-700);\n line-height: 1.5;\n }\n\n \/* \u2500\u2500\u2500 CALCULATOR \u2500\u2500\u2500 *\/\n .calc-wrap {\n background: var(--white);\n border-radius: var(--radius-lg);\n box-shadow: var(--shadow-lg);\n overflow: hidden;\n border: 1px solid var(--blue-200);\n }\n .calc-header {\n background: linear-gradient(135deg, var(--blue-700), var(--blue-500));\n color: var(--white);\n padding: 20px 24px;\n }\n .calc-header h2 {\n font-family: 'Playfair Display', serif;\n font-size: 20px;\n font-weight: 700;\n margin-bottom: 4px;\n }\n .calc-header p {\n font-size: 13px;\n opacity: .8;\n }\n .calc-body {\n padding: 24px;\n }\n .calc-grid {\n display: grid;\n grid-template-columns: 1fr 1fr;\n gap: 16px;\n }\n @media (max-width: 600px) {\n .calc-grid { grid-template-columns: 1fr; }\n }\n .calc-field label {\n display: block;\n font-size: 13px;\n font-weight: 600;\n color: var(--gray-700);\n margin-bottom: 6px;\n }\n .calc-field select,\n .calc-field input {\n width: 100%;\n padding: 10px 14px;\n border: 1px solid var(--gray-300);\n border-radius: var(--radius-sm);\n font-size: 15px;\n font-family: inherit;\n background: var(--white);\n transition: border-color .2s;\n }\n .calc-field select:focus,\n .calc-field input:focus {\n outline: none;\n border-color: var(--blue-500);\n box-shadow: 0 0 0 3px rgba(25,118,210,.15);\n }\n .calc-btn {\n grid-column: 1 \/ -1;\n background: linear-gradient(135deg, var(--blue-600), var(--blue-500));\n color: var(--white);\n border: none;\n padding: 12px;\n border-radius: var(--radius-sm);\n font-size: 15px;\n font-weight: 600;\n cursor: pointer;\n transition: transform .15s, box-shadow .15s;\n margin-top: 4px;\n }\n .calc-btn:hover {\n transform: translateY(-1px);\n box-shadow: var(--shadow-md);\n }\n .calc-btn:active {\n transform: translateY(0);\n }\n .calc-result {\n grid-column: 1 \/ -1;\n border-radius: var(--radius-md);\n padding: 20px;\n text-align: center;\n display: none;\n animation: fadeSlide .3s ease;\n }\n @keyframes fadeSlide {\n from { opacity: 0; transform: translateY(8px); }\n to { opacity: 1; transform: translateY(0); }\n }\n .calc-result.show { display: block; }\n .calc-result-zone {\n font-family: 'Playfair Display', serif;\n font-size: 36px;\n font-weight: 800;\n margin-bottom: 6px;\n }\n .calc-result-label {\n font-size: 15px;\n font-weight: 600;\n margin-bottom: 4px;\n }\n .calc-result-desc {\n font-size: 13px;\n color: var(--gray-700);\n }\n .calc-result-bar {\n margin-top: 16px;\n height: 8px;\n border-radius: 4px;\n background: var(--gray-200);\n position: relative;\n overflow: hidden;\n }\n .calc-result-bar-fill {\n height: 100%;\n border-radius: 4px;\n transition: width .5s ease;\n }\n .calc-result-details {\n margin-top: 14px;\n font-size: 13px;\n color: var(--gray-600);\n text-align: left;\n }\n .calc-result-details strong { color: var(--gray-800); }\n\n \/* \u2500\u2500\u2500 GROUPS TABLE \u2500\u2500\u2500 *\/\n .groups-table-wrap {\n background: var(--white);\n border-radius: var(--radius-lg);\n box-shadow: var(--shadow-md);\n overflow: hidden;\n border: 1px solid var(--beige-300);\n }\n .groups-table {\n width: 100%;\n border-collapse: collapse;\n font-size: 14px;\n }\n .groups-table thead th {\n background: var(--beige-200);\n color: var(--gray-800);\n padding: 12px 16px;\n text-align: left;\n font-weight: 600;\n font-size: 13px;\n border-bottom: 2px solid var(--beige-300);\n }\n .groups-table tbody td {\n padding: 14px 16px;\n border-bottom: 1px solid var(--gray-200);\n vertical-align: top;\n }\n .groups-table tbody tr:last-child td { border-bottom: none; }\n .groups-table tbody tr:hover { background: var(--beige-100); }\n .groups-table .group-num {\n font-weight: 700;\n color: var(--blue-700);\n font-size: 15px;\n }\n\n \/* \u2500\u2500\u2500 VISUAL BAR CHART \u2500\u2500\u2500 *\/\n .bar-chart {\n margin-top: 20px;\n }\n .bar-row {\n display: flex;\n align-items: center;\n margin-bottom: 10px;\n gap: 12px;\n }\n .bar-label {\n width: 70px;\n font-size: 13px;\n font-weight: 600;\n text-align: right;\n flex-shrink: 0;\n color: var(--gray-700);\n }\n .bar-track {\n flex: 1;\n height: 32px;\n background: var(--gray-100);\n border-radius: 6px;\n display: flex;\n overflow: hidden;\n position: relative;\n }\n .bar-seg {\n display: flex;\n align-items: center;\n justify-content: center;\n font-size: 11px;\n font-weight: 700;\n color: var(--white);\n transition: all .3s;\n min-width: 20px;\n }\n .bar-seg span {\n text-shadow: 0 1px 2px rgba(0,0,0,.3);\n }\n\n \/* \u2500\u2500\u2500 CONTENT STYLES \u2500\u2500\u2500 *\/\n h2.section-title {\n font-family: 'Playfair Display', serif;\n font-size: clamp(22px, 3vw, 30px);\n font-weight: 800;\n color: var(--blue-900);\n margin-bottom: 8px;\n letter-spacing: -0.3px;\n }\n h3.subsection-title {\n font-size: 18px;\n font-weight: 700;\n color: var(--blue-800);\n margin: 32px 0 12px;\n }\n .section-lead {\n font-size: 16px;\n color: var(--gray-600);\n margin-bottom: 24px;\n max-width: 700px;\n }\n .content p {\n margin-bottom: 16px;\n color: var(--gray-800);\n }\n .content a {\n color: var(--blue-600);\n text-decoration: none;\n border-bottom: 1px solid var(--blue-200);\n transition: border-color .2s;\n }\n .content a:hover {\n border-bottom-color: var(--blue-500);\n }\n\n \/* \u2500\u2500\u2500 INFO CARDS \u2500\u2500\u2500 *\/\n .info-grid {\n display: grid;\n grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));\n gap: 16px;\n margin: 24px 0;\n }\n .info-card {\n background: var(--white);\n border-radius: var(--radius-md);\n padding: 20px;\n border: 1px solid var(--gray-200);\n transition: box-shadow .2s;\n }\n .info-card:hover {\n box-shadow: var(--shadow-md);\n }\n .info-card-icon {\n width: 40px;\n height: 40px;\n border-radius: var(--radius-sm);\n display: flex;\n align-items: center;\n justify-content: center;\n font-size: 20px;\n margin-bottom: 12px;\n }\n .info-card-icon.blue { background: var(--blue-100); }\n .info-card-icon.beige { background: var(--beige-200); }\n .info-card-icon.green { background: var(--zone-a-bg); }\n .info-card-icon.orange { background: var(--zone-c-bg); }\n .info-card h4 {\n font-size: 15px;\n font-weight: 700;\n margin-bottom: 6px;\n color: var(--blue-900);\n }\n .info-card p {\n font-size: 13px;\n color: var(--gray-600);\n line-height: 1.6;\n }\n\n \/* \u2500\u2500\u2500 CALLOUT BOX \u2500\u2500\u2500 *\/\n .callout {\n border-radius: var(--radius-md);\n padding: 20px 24px;\n margin: 24px 0;\n }\n .callout-blue {\n background: var(--blue-50);\n border-left: 4px solid var(--blue-500);\n }\n .callout-beige {\n background: var(--beige-100);\n border-left: 4px solid var(--beige-400);\n }\n .callout-warn {\n background: var(--zone-c-bg);\n border-left: 4px solid var(--zone-c);\n }\n .callout strong {\n display: block;\n margin-bottom: 6px;\n font-size: 14px;\n }\n .callout p {\n font-size: 14px;\n color: var(--gray-700);\n margin: 0;\n }\n\n \/* \u2500\u2500\u2500 MEASUREMENT TABLE \u2500\u2500\u2500 *\/\n .meas-table {\n width: 100%;\n border-collapse: collapse;\n font-size: 14px;\n margin: 16px 0;\n }\n .meas-table thead th {\n background: var(--blue-100);\n color: var(--blue-900);\n padding: 10px 14px;\n text-align: left;\n font-weight: 600;\n font-size: 13px;\n }\n .meas-table tbody td {\n padding: 10px 14px;\n border-bottom: 1px solid var(--gray-200);\n }\n .meas-table tbody tr:last-child td { border-bottom: none; }\n\n \/* \u2500\u2500\u2500 EXAMPLE BOX \u2500\u2500\u2500 *\/\n .example-box {\n background: var(--white);\n border: 2px solid var(--blue-200);\n border-radius: var(--radius-lg);\n overflow: hidden;\n margin: 24px 0;\n }\n .example-box-header {\n background: var(--blue-100);\n padding: 14px 20px;\n font-weight: 700;\n color: var(--blue-800);\n font-size: 15px;\n }\n .example-box-body {\n padding: 20px;\n }\n .example-box-body p {\n margin-bottom: 8px;\n font-size: 14px;\n }\n .example-result {\n margin-top: 12px;\n padding: 14px 18px;\n border-radius: var(--radius-sm);\n font-weight: 600;\n }\n .example-result.zone-c-result {\n background: var(--zone-c-bg);\n color: var(--zone-c);\n border: 1px solid var(--zone-c-light);\n }\n\n \/* \u2500\u2500\u2500 FOOTER SECTION \u2500\u2500\u2500 *\/\n .footer-section {\n background: var(--blue-900);\n color: var(--white);\n padding: 40px 24px;\n }\n .footer-inner {\n max-width: 960px;\n margin: 0 auto;\n }\n .footer-inner h2 {\n font-family: 'Playfair Display', serif;\n font-size: 22px;\n margin-bottom: 12px;\n }\n .footer-inner p {\n color: var(--blue-200);\n font-size: 14px;\n margin-bottom: 8px;\n }\n .footer-inner a {\n color: var(--blue-300);\n }\n .footer-link-back {\n display: inline-block;\n margin-top: 20px;\n padding: 10px 20px;\n background: rgba(255,255,255,.1);\n border: 1px solid rgba(255,255,255,.2);\n border-radius: var(--radius-sm);\n color: var(--white);\n text-decoration: none;\n font-size: 14px;\n font-weight: 600;\n transition: background .2s;\n }\n .footer-link-back:hover {\n background: rgba(255,255,255,.2);\n }\n\n \/* \u2500\u2500\u2500 SHOP SHORTCODE PLACEHOLDER \u2500\u2500\u2500 *\/\n .shop-placeholder {\n padding: 0 24px;\n }\n .shop-placeholder-inner {\n max-width: 960px;\n margin: 0 auto;\n }\n\n \/* \u2500\u2500\u2500 IMPERIAL TABLE \u2500\u2500\u2500 *\/\n .imperial-table-wrap {\n background: var(--white);\n border-radius: var(--radius-lg);\n box-shadow: var(--shadow-md);\n overflow: hidden;\n border: 1px solid var(--beige-300);\n margin-top: 24px;\n }\n .imperial-header {\n background: var(--beige-200);\n padding: 16px 20px;\n }\n .imperial-header h3 {\n font-size: 16px;\n font-weight: 700;\n color: var(--gray-800);\n margin-bottom: 2px;\n }\n .imperial-header p {\n font-size: 12px;\n color: var(--gray-600);\n }\n\n \/* \u2500\u2500\u2500 RESPONSIVE \u2500\u2500\u2500 *\/\n @media (max-width: 768px) {\n .hero { padding: 32px 20px 40px; }\n .section { padding: 36px 0; }\n .limits-table { font-size: 13px; }\n .limits-table thead th,\n .limits-table tbody td { padding: 10px 10px; }\n .zone-legend { grid-template-columns: 1fr 1fr; }\n .info-grid { grid-template-columns: 1fr; }\n .bar-label { width: 60px; font-size: 12px; }\n }\n @media (max-width: 480px) {\n .zone-legend { grid-template-columns: 1fr; }\n .limits-table .zone-val { font-size: 13px; padding: 3px 8px; min-width: 48px; }\n }\n <\/style>\n<\/head>\n<body>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 HERO \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<header class=\"hero\">\n <div class=\"hero-inner\">\n <nav class=\"hero-breadcrumb\">\n <a href=\"https:\/\/vibromera.eu\/\">Home<\/a>\n <span>\u203a<\/span>\n <a href=\"https:\/\/vibromera.eu\/glossary\/\">Glossary<\/a>\n <span>\u203a<\/span>\n <a href=\"https:\/\/vibromera.eu\/glossary\/#iso-standards\">ISO Standards<\/a>\n <span>\u203a<\/span>\n ISO 10816-3\n <\/nav>\n <div class=\"hero-badge\">International Standard<\/div>\n <h1>ISO 10816-3: Vibration Limits for Industrial Machines<\/h1>\n <p class=\"hero-subtitle\">The practical standard providing specific RMS velocity limits and evaluation zones for pumps, motors, fans, compressors, and other industrial machines rated 15 kW and above.<\/p>\n <\/div>\n<\/header>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 QUICK NAV \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<nav class=\"quick-nav\">\n <div class=\"quick-nav-inner\">\n <a href=\"#limits-table\">Limits Table<\/a>\n <a href=\"#calculator\">Calculator<\/a>\n <a href=\"#visual\">Visual Chart<\/a>\n <a href=\"#groups\">Machine Groups<\/a>\n <a href=\"#scope\">Scope<\/a>\n <a href=\"#application\">Application<\/a>\n <a href=\"#examples\">Examples<\/a>\n <a href=\"#faq\">FAQ<\/a>\n <\/div>\n<\/nav>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SHOP \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<div class=\"shop-placeholder\" style=\"padding-top: 24px;\">\n <div class=\"shop-placeholder-inner\">\n\n <\/div>\n<\/div>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: LIMITS TABLE + CALCULATOR \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section section-blue\" id=\"limits-table\">\n <div class=\"container\">\n <h2 class=\"section-title\">Quick Reference: Vibration Severity Limits<\/h2>\n <p class=\"section-lead\">Measure broadband RMS velocity (mm\/s) on the bearing housing. Classify your machine, then find your zone below.<\/p>\n\n <div class=\"shorts-grid\">\n <!-- \u2500\u2500 PRIMARY TABLE \u2500\u2500 -->\n <div class=\"limits-table-wrap\">\n <div class=\"limits-table-header\">\n <h2>Evaluation Criteria \u2014 RMS Velocity (mm\/s)<\/h2>\n <p>ISO 10816-3 zone boundary values for industrial machines<\/p>\n <\/div>\n <table class=\"limits-table\">\n <thead>\n <tr>\n <th>Machine Group<\/th>\n <th>Zone A \/ B<\/th>\n <th>Zone B \/ C<\/th>\n <th>Zone C \/ D<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td>\n <strong>Group 1<\/strong>\n <span class=\"group-tag\">Large, rigid foundation, >300 kW<\/span>\n <\/td>\n <td><span class=\"zone-val zone-a-val\">0.71<\/span><\/td>\n <td><span class=\"zone-val zone-b-val\">1.8<\/span><\/td>\n <td><span class=\"zone-val zone-c-val\">4.5<\/span><\/td>\n <\/tr>\n <tr class=\"most-common\">\n <td>\n <strong>Group 2 \u2605<\/strong>\n <span class=\"group-tag\">Medium, rigid foundation, 15\u2013300 kW<\/span>\n <\/td>\n <td><span class=\"zone-val zone-a-val\">1.12<\/span><\/td>\n <td><span class=\"zone-val zone-b-val\">2.8<\/span><\/td>\n <td><span class=\"zone-val zone-c-val\">7.1<\/span><\/td>\n <\/tr>\n <tr>\n <td>\n <strong>Group 3<\/strong>\n <span class=\"group-tag\">Large, flexible foundation, >300 kW<\/span>\n <\/td>\n <td><span class=\"zone-val zone-a-val\">1.8<\/span><\/td>\n <td><span class=\"zone-val zone-b-val\">4.5<\/span><\/td>\n <td><span class=\"zone-val zone-c-val\">11.2<\/span><\/td>\n <\/tr>\n <tr>\n <td>\n <strong>Group 4<\/strong>\n <span class=\"group-tag\">Medium, flexible foundation, 15\u2013300 kW<\/span>\n <\/td>\n <td><span class=\"zone-val zone-a-val\">2.8<\/span><\/td>\n <td><span class=\"zone-val zone-b-val\">7.1<\/span><\/td>\n <td><span class=\"zone-val zone-c-val\">18.0<\/span><\/td>\n <\/tr>\n <\/tbody>\n <\/table>\n <!-- Zone Legend -->\n <div class=\"zone-legend\">\n <div class=\"zone-card zone-card-a\">\n <div>\n <strong style=\"color:var(--zone-a);\">Zone A \u2014 Good<\/strong>\n <p>Newly commissioned machines. Typical of new or recently overhauled equipment in excellent condition.<\/p>\n <\/div>\n <\/div>\n <div class=\"zone-card zone-card-b\">\n <div>\n <strong style=\"color:var(--zone-b);\">Zone B \u2014 Satisfactory<\/strong>\n <p>Acceptable for unrestricted long-term operation. Most well-maintained machines operate here.<\/p>\n <\/div>\n <\/div>\n <div class=\"zone-card zone-card-c\">\n <div>\n <strong style=\"color:var(--zone-c);\">Zone C \u2014 Unsatisfactory<\/strong>\n <p>Not suitable for continuous operation. Investigate root cause and plan corrective maintenance.<\/p>\n <\/div>\n <\/div>\n <div class=\"zone-card zone-card-d\">\n <div>\n <strong style=\"color:var(--zone-d);\">Zone D \u2014 Unacceptable<\/strong>\n <p>Danger of damage. Immediate shutdown and corrective action required to prevent failure.<\/p>\n <\/div>\n <\/div>\n <\/div>\n <\/div>\n\n <!-- \u2500\u2500 IMPERIAL TABLE \u2500\u2500 -->\n <div class=\"imperial-table-wrap\">\n <div class=\"imperial-header\">\n <h3>Imperial Units \u2014 RMS Velocity (in\/s)<\/h3>\n <p>Equivalent values for regions using imperial measurement system (1 mm\/s \u2248 0.03937 in\/s)<\/p>\n <\/div>\n <table class=\"limits-table\">\n <thead>\n <tr>\n <th>Machine Group<\/th>\n <th>Zone A \/ B<\/th>\n <th>Zone B \/ C<\/th>\n <th>Zone C \/ D<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td><strong>Group 1<\/strong><\/td>\n <td><span class=\"zone-val zone-a-val\">0.028<\/span><\/td>\n <td><span class=\"zone-val zone-b-val\">0.071<\/span><\/td>\n <td><span class=\"zone-val zone-c-val\">0.177<\/span><\/td>\n <\/tr>\n <tr class=\"most-common\">\n <td><strong>Group 2 \u2605<\/strong><\/td>\n <td><span class=\"zone-val zone-a-val\">0.044<\/span><\/td>\n <td><span class=\"zone-val zone-b-val\">0.110<\/span><\/td>\n <td><span class=\"zone-val zone-c-val\">0.280<\/span><\/td>\n <\/tr>\n <tr>\n <td><strong>Group 3<\/strong><\/td>\n <td><span class=\"zone-val zone-a-val\">0.071<\/span><\/td>\n <td><span class=\"zone-val zone-b-val\">0.177<\/span><\/td>\n <td><span class=\"zone-val zone-c-val\">0.441<\/span><\/td>\n <\/tr>\n <tr>\n <td><strong>Group 4<\/strong><\/td>\n <td><span class=\"zone-val zone-a-val\">0.110<\/span><\/td>\n <td><span class=\"zone-val zone-b-val\">0.280<\/span><\/td>\n <td><span class=\"zone-val zone-c-val\">0.709<\/span><\/td>\n <\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: CALCULATOR \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section\" id=\"calculator\">\n <div class=\"container\">\n <div class=\"calc-wrap\">\n <div class=\"calc-header\">\n <h2>\u26a1 Vibration Zone Calculator<\/h2>\n <p>Enter your machine parameters and measured vibration to instantly determine the ISO 10816-3 zone<\/p>\n <\/div>\n <div class=\"calc-body\">\n <div class=\"calc-grid\">\n <div class=\"calc-field\">\n <label for=\"calc-power\">Power Rating<\/label>\n <select id=\"calc-power\">\n <option value=\"medium\">15 \u2013 300 kW (Medium)<\/option>\n <option value=\"large\">Above 300 kW (Large)<\/option>\n <\/select>\n <\/div>\n <div class=\"calc-field\">\n <label for=\"calc-foundation\">Foundation Type<\/label>\n <select id=\"calc-foundation\">\n <option value=\"rigid\">Rigid (concrete, steel)<\/option>\n <option value=\"flexible\">Flexible (spring, rubber)<\/option>\n <\/select>\n <\/div>\n <div class=\"calc-field\">\n <label for=\"calc-vibration\">Measured RMS Velocity (mm\/s)<\/label>\n <input type=\"number\" id=\"calc-vibration\" step=\"0.01\" min=\"0\" placeholder=\"e.g. 3.5\">\n <\/div>\n <div class=\"calc-field\">\n <label for=\"calc-unit\">Units<\/label>\n <select id=\"calc-unit\">\n <option value=\"mm\">mm\/s<\/option>\n <option value=\"in\">in\/s<\/option>\n <\/select>\n <\/div>\n <button class=\"calc-btn\" onclick=\"evaluateVibration()\">Evaluate Vibration Zone<\/button>\n <div class=\"calc-result\" id=\"calc-result\"><\/div>\n <\/div>\n <\/div>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: VISUAL BAR CHART \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section section-alt\" id=\"visual\">\n <div class=\"container\">\n <h2 class=\"section-title\">Visual Comparison of Zone Boundaries<\/h2>\n <p class=\"section-lead\">The proportional width of each zone shows how limits expand for flexibly mounted and larger machines.<\/p>\n\n <div class=\"bar-chart\">\n <div class=\"bar-row\">\n <div class=\"bar-label\">Group 1<\/div>\n <div class=\"bar-track\">\n <div class=\"bar-seg\" style=\"width:3.9%;background:var(--zone-a);\" title=\"Zone A: 0\u20130.71\"><span><\/span><\/div>\n <div class=\"bar-seg\" style=\"width:6.1%;background:var(--zone-b);\" title=\"Zone B: 0.71\u20131.8\"><span>1.8<\/span><\/div>\n <div class=\"bar-seg\" style=\"width:15%;background:var(--zone-c);\" title=\"Zone C: 1.8\u20134.5\"><span>4.5<\/span><\/div>\n <div class=\"bar-seg\" style=\"width:75%;background:var(--zone-d);\" title=\"Zone D: >4.5\"><span>D<\/span><\/div>\n <\/div>\n <\/div>\n <div class=\"bar-row\">\n <div class=\"bar-label\">Group 2 \u2605<\/div>\n <div class=\"bar-track\">\n <div class=\"bar-seg\" style=\"width:6.2%;background:var(--zone-a);\" title=\"Zone A: 0\u20131.12\"><span><\/span><\/div>\n <div class=\"bar-seg\" style=\"width:9.3%;background:var(--zone-b);\" title=\"Zone B: 1.12\u20132.8\"><span>2.8<\/span><\/div>\n <div class=\"bar-seg\" style=\"width:24%;background:var(--zone-c);\" title=\"Zone C: 2.8\u20137.1\"><span>7.1<\/span><\/div>\n <div class=\"bar-seg\" style=\"width:60.5%;background:var(--zone-d);\" title=\"Zone D: >7.1\"><span>D<\/span><\/div>\n <\/div>\n <\/div>\n <div class=\"bar-row\">\n <div class=\"bar-label\">Group 3<\/div>\n <div class=\"bar-track\">\n <div class=\"bar-seg\" style=\"width:10%;background:var(--zone-a);\" title=\"Zone A: 0\u20131.8\"><span><\/span><\/div>\n <div class=\"bar-seg\" style=\"width:15%;background:var(--zone-b);\" title=\"Zone B: 1.8\u20134.5\"><span>4.5<\/span><\/div>\n <div class=\"bar-seg\" style=\"width:37%;background:var(--zone-c);\" title=\"Zone C: 4.5\u201311.2\"><span>11.2<\/span><\/div>\n <div class=\"bar-seg\" style=\"width:38%;background:var(--zone-d);\" title=\"Zone D: >11.2\"><span>D<\/span><\/div>\n <\/div>\n <\/div>\n <div class=\"bar-row\">\n <div class=\"bar-label\">Group 4<\/div>\n <div class=\"bar-track\">\n <div class=\"bar-seg\" style=\"width:15.6%;background:var(--zone-a);\" title=\"Zone A: 0\u20132.8\"><span><\/span><\/div>\n <div class=\"bar-seg\" style=\"width:23.9%;background:var(--zone-b);\" title=\"Zone B: 2.8\u20137.1\"><span>7.1<\/span><\/div>\n <div class=\"bar-seg\" style=\"width:40%;background:var(--zone-c);\" title=\"Zone C: 7.1\u201318\"><span>18<\/span><\/div>\n <div class=\"bar-seg\" style=\"width:20.5%;background:var(--zone-d);\" title=\"Zone D: >18\"><span>D<\/span><\/div>\n <\/div>\n <\/div>\n <\/div>\n <div style=\"display:flex;gap:16px;margin-top:16px;flex-wrap:wrap;\">\n <span style=\"display:flex;align-items:center;gap:6px;font-size:12px;color:var(--gray-600);\"><span style=\"width:14px;height:14px;border-radius:3px;background:var(--zone-a);display:inline-block;\"><\/span> Zone A<\/span>\n <span style=\"display:flex;align-items:center;gap:6px;font-size:12px;color:var(--gray-600);\"><span style=\"width:14px;height:14px;border-radius:3px;background:var(--zone-b);display:inline-block;\"><\/span> Zone B<\/span>\n <span style=\"display:flex;align-items:center;gap:6px;font-size:12px;color:var(--gray-600);\"><span style=\"width:14px;height:14px;border-radius:3px;background:var(--zone-c);display:inline-block;\"><\/span> Zone C<\/span>\n <span style=\"display:flex;align-items:center;gap:6px;font-size:12px;color:var(--gray-600);\"><span style=\"width:14px;height:14px;border-radius:3px;background:var(--zone-d);display:inline-block;\"><\/span> Zone D<\/span>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: SUMMARY \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section\">\n <div class=\"container content\">\n <h2 class=\"section-title\">What is ISO 10816-3?<\/h2>\n <p>ISO 10816-3 is one of the most widely referenced industrial vibration standards in the world. Published by the International Organization for Standardization, it provides specific numerical limits for vibration severity on common rotating industrial machines. It serves as the direct, practical application of the general framework established in <a href=\"https:\/\/vibromera.eu\/glossary\/iso-10816-1\/\">ISO 10816-1<\/a>: while Part 1 explains the general principles of how to measure and evaluate machine vibration, Part 3 gives you the actual numbers\u2014the RMS velocity values in mm\/s\u2014that define whether a machine's vibration is acceptable or dangerous.<\/p>\n\n <p>The standard divides vibration severity into four evaluation zones (A through D) for four different machine groups, based on power rating and foundation type. This simple matrix gives maintenance engineers, plant operators, and condition monitoring technicians a clear, internationally agreed framework for making go\/no-go decisions about equipment health.<\/p>\n\n <div class=\"callout callout-beige\">\n <strong>\ud83d\udccc Succession Note<\/strong>\n <p>ISO 10816-3 has been formally superseded by ISO 20816-3 (published in 2022), which updates measurement methodology and adds shaft vibration criteria. However, the core zone boundary values remain highly relevant, and the vast majority of industrial monitoring systems, plant procedures, and maintenance programs worldwide continue to reference ISO 10816-3 limits. Both standards can be used in parallel during the transition period.<\/p>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: SCOPE \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section section-alt\" id=\"scope\">\n <div class=\"container content\">\n <h2 class=\"section-title\">Scope and Applicability<\/h2>\n <p>ISO 10816-3 applies to a broad range of industrial rotating machinery. Understanding whether your equipment falls within the scope of this standard is essential before applying the zone boundary values.<\/p>\n\n <h3 class=\"subsection-title\">Machines Covered<\/h3>\n <p>The standard is designed for the most common types of industrial rotating equipment operating under normal steady-state conditions. This includes centrifugal pumps, electric motors and generators (both induction and synchronous), blowers and fans (centrifugal and axial), centrifugal compressors, and gear units integrated into machine trains. The machines must have a power output (or nominal power) above 15 kW, and must operate at speeds between 120 RPM and 15,000 RPM. Measurements are taken exclusively on the non-rotating parts of the machine \u2014 specifically bearing housings, bearing pedestals, or structural parts that respond directly to the dynamic forces transmitted through the bearings.<\/p>\n\n <h3 class=\"subsection-title\">Machines Excluded<\/h3>\n <p>Several categories of machinery fall outside the scope of ISO 10816-3 and are covered by their own dedicated standards. Reciprocating machinery such as diesel engines and reciprocating compressors follow ISO 10816-6. Machine tools with their unique vibration characteristics follow ISO 10816-8. Hydraulic power generating sets and pumps in power stations follow ISO 10816-5. Steam turbines with outputs above 50 MW and gas turbines above 3 MW follow ISO 10816-2. Single-cylinder machines and machines with rotating masses that are not rigidly connected to the rotor are also excluded.<\/p>\n\n <div class=\"info-grid\">\n <div class=\"info-card\">\n <div class=\"info-card-icon blue\">\ud83d\udd27<\/div>\n <h4>Power Range<\/h4>\n <p>Applies to machines rated above 15 kW. Equipment below this threshold typically has different vibration characteristics and is evaluated using manufacturer specifications or other criteria.<\/p>\n <\/div>\n <div class=\"info-card\">\n <div class=\"info-card-icon beige\">\u2699\ufe0f<\/div>\n <h4>Speed Range<\/h4>\n <p>Valid for operating speeds of 120 to 15,000 RPM. This covers the vast majority of industrial rotating equipment from slow gear-driven machinery to high-speed turbomachinery.<\/p>\n <\/div>\n <div class=\"info-card\">\n <div class=\"info-card-icon green\">\ud83d\udccf<\/div>\n <h4>Measurement Location<\/h4>\n <p>All measurements must be taken on non-rotating parts: bearing housings, pedestals, or structural parts that directly respond to rotor dynamic forces.<\/p>\n <\/div>\n <div class=\"info-card\">\n <div class=\"info-card-icon orange\">\ud83d\udcca<\/div>\n <h4>Measurement Parameter<\/h4>\n <p>Broadband <a href=\"https:\/\/vibromera.eu\/glossary\/rms\/\">RMS velocity<\/a> in mm\/s is the primary evaluation parameter. This single number captures the overall vibration severity across a wide frequency range (typically 10\u20131000 Hz).<\/p>\n <\/div>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: MACHINE GROUPS \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section\" id=\"groups\">\n <div class=\"container content\">\n <h2 class=\"section-title\">Machine Classification: The Four Groups<\/h2>\n <p>Correctly classifying your machine is the most critical step in applying ISO 10816-3. The standard divides industrial machines into four groups based on two key factors: power rating and foundation type. Applying the wrong group can lead to either false alarms (evaluating a flexibly mounted machine against rigid-mount limits) or missed defects (applying lenient limits to a rigidly mounted machine where lower vibration is expected and achievable).<\/p>\n\n <div class=\"groups-table-wrap\" style=\"margin: 24px 0;\">\n <table class=\"groups-table\">\n <thead>\n <tr>\n <th>Group<\/th>\n <th>Power<\/th>\n <th>Foundation<\/th>\n <th>Typical Machines<\/th>\n <th>Key Characteristic<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td class=\"group-num\">1<\/td>\n <td>> 300 kW<\/td>\n <td>Rigid<\/td>\n <td>Large pumps, compressors, generators on concrete pads<\/td>\n <td>Tightest limits \u2014 massive rotors, precision bearings, heavy foundations absorb vibration<\/td>\n <\/tr>\n <tr style=\"background:var(--blue-50);\">\n <td class=\"group-num\">2 \u2605<\/td>\n <td>15\u2013300 kW<\/td>\n <td>Rigid<\/td>\n <td>Standard motors, medium pumps, fans, blowers on concrete or steel base<\/td>\n <td>Most common group \u2014 covers the majority of plant equipment<\/td>\n <\/tr>\n <tr>\n <td class=\"group-num\">3<\/td>\n <td>> 300 kW<\/td>\n <td>Flexible<\/td>\n <td>Large machines on spring isolators, rubber mounts, or elevated platforms<\/td>\n <td>Wider limits \u2014 flexible mounts allow higher machine vibration while protecting the structure<\/td>\n <\/tr>\n <tr>\n <td class=\"group-num\">4<\/td>\n <td>15\u2013300 kW<\/td>\n <td>Flexible<\/td>\n <td>Medium machines on spring or rubber mounts, pipe-mounted pumps<\/td>\n <td>Most lenient limits \u2014 combination of moderate size and flexible mounting<\/td>\n <\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <h3 class=\"subsection-title\">How to Determine Foundation Type<\/h3>\n <p>The distinction between rigid and flexible foundations is critical and can sometimes be ambiguous in practice. A rigid foundation is one where the natural frequency of the machine-foundation system is significantly higher than the principal excitation frequency (typically the machine's running speed). In practical terms, this usually means the machine is bolted directly to a heavy concrete pad, thick steel baseplate, or structural floor without any isolation elements. The foundation mass should be at least 3\u20135 times the machine mass for it to be considered truly rigid.<\/p>\n\n <p>A flexible foundation is one that includes deliberate vibration isolation elements \u2014 spring isolators, rubber pads, cork layers, or inertia blocks on springs \u2014 or where the machine is mounted on an elevated structure (such as a mezzanine or pipe bridge) that has its own significant flexibility. The key test is whether the foundation noticeably moves or resonates when the machine is running. If you can feel vibration on the floor or structure around the machine, the foundation is likely behaving as flexible.<\/p>\n\n <div class=\"callout callout-blue\">\n <strong>\ud83d\udca1 Practical Tip<\/strong>\n <p>If you are unsure whether a foundation is rigid or flexible, measuring the vibration on both the machine bearing housing and the foundation surface can help. If the foundation vibration is more than 50% of the bearing housing vibration at running speed, the foundation is likely flexible and Group 3 or Group 4 limits should be used.<\/p>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: APPLICATION \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section section-blue\" id=\"application\">\n <div class=\"container content\">\n <h2 class=\"section-title\">Guidance on Practical Application<\/h2>\n <p>ISO 10816-3 distinguishes between two fundamentally different use cases: evaluating the condition of new or repaired machines (acceptance testing), and monitoring machines already in service (operational monitoring). Each use case has its own methodology and criteria.<\/p>\n\n <h3 class=\"subsection-title\">Acceptance Testing of New\/Repaired Equipment<\/h3>\n <p>When commissioning a new machine, accepting a machine after installation, or returning a machine to service after a major overhaul, the vibration level should ideally be within Zone A. Zone B is considered acceptable for newly commissioned equipment, but if a brand-new machine reads Zone B, it may indicate an installation issue (misalignment, soft foot, piping strain) that is worth investigating before it causes premature bearing wear. Any new machine exhibiting Zone C or Zone D vibration should not be accepted until the problem is found and corrected. The acceptance criteria should be documented in the purchase or overhaul contract, explicitly referencing ISO 10816-3 group and zone requirements.<\/p>\n\n <h3 class=\"subsection-title\">Operational Monitoring of In-Service Equipment<\/h3>\n <p>For machines already in service, the standard provides two complementary evaluation approaches. Absolute vibration assessment compares the current broadband RMS velocity against the zone limits for the machine's group. If the reading is in Zone A or B, the machine is acceptable. Zone C means the machine can run for a limited period while corrective maintenance is planned. Zone D requires immediate shutdown to prevent catastrophic damage.<\/p>\n\n <p>Trend-based assessment is equally important. A sudden increase in vibration \u2014 even if the reading remains within Zone B \u2014 is a significant change that warrants investigation. A machine that has been running at 1.0 mm\/s for years and suddenly jumps to 2.2 mm\/s is still in Zone B for Group 2, but the change of 1.2 mm\/s represents a developing fault that will continue to worsen. The standard recommends establishing baselines for each machine and tracking changes over time, not just checking against absolute limits.<\/p>\n\n <h3 class=\"subsection-title\">Measurement Procedures<\/h3>\n <p>The standard specifies that vibration measurements should be taken at each accessible bearing location in three orthogonal directions: horizontal (perpendicular to the shaft axis), vertical, and axial (parallel to the shaft axis). The highest reading from any direction at any bearing is used for the overall machine evaluation. This \"worst case\" approach ensures that directional vibration patterns (such as misalignment that primarily manifests in the axial direction) are not overlooked.<\/p>\n\n <table class=\"meas-table\">\n <thead>\n <tr>\n <th>Direction<\/th>\n <th>Abbreviation<\/th>\n <th>Common Defects Detected<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td>Horizontal (perpendicular to shaft)<\/td>\n <td>H<\/td>\n <td>Unbalance, looseness, bearing wear<\/td>\n <\/tr>\n <tr>\n <td>Vertical<\/td>\n <td>V<\/td>\n <td>Unbalance, structural resonance<\/td>\n <\/tr>\n <tr>\n <td>Axial (parallel to shaft)<\/td>\n <td>A<\/td>\n <td>Misalignment, bent shaft, thrust bearing faults<\/td>\n <\/tr>\n <\/tbody>\n <\/table>\n\n <div class=\"callout callout-warn\">\n <strong>\u26a0\ufe0f Important Limitation<\/strong>\n <p>ISO 10816-3 is a broadband screening tool. It tells you <em>that<\/em> a problem exists (by placing the machine in Zone C or D), but it does not tell you <em>what<\/em> the problem is. To diagnose the specific fault \u2014 whether it is unbalance, misalignment, bearing damage, or something else \u2014 you need <a href=\"https:\/\/vibromera.eu\/glossary\/spectral-analysis\/\">frequency spectrum analysis<\/a> using a vibration analyzer or portable balancing system.<\/p>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: PRACTICAL EXAMPLES \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section\" id=\"examples\">\n <div class=\"container content\">\n <h2 class=\"section-title\">Practical Examples<\/h2>\n <p class=\"section-lead\">Step-by-step evaluations using ISO 10816-3 zone criteria.<\/p>\n\n <div class=\"example-box\">\n <div class=\"example-box-header\">Example 1: Evaluating a 75 kW Centrifugal Pump<\/div>\n <div class=\"example-box-body\">\n <p><strong>Machine:<\/strong> Centrifugal pump driven by a 75 kW electric motor<\/p>\n <p><strong>Foundation:<\/strong> Bolted to a concrete pad (rigid foundation)<\/p>\n <p><strong>Classification:<\/strong> Group 2 (15\u2013300 kW, rigid foundation)<\/p>\n <p><strong>Measured vibration:<\/strong> 3.5 mm\/s RMS on the pump drive-end bearing, horizontal direction<\/p>\n <p><strong>Group 2 boundaries:<\/strong> A\/B = 1.12 mm\/s \u00b7 B\/C = 2.8 mm\/s \u00b7 C\/D = 7.1 mm\/s<\/p>\n <div class=\"example-result zone-c-result\">\n <strong>Result: Zone C \u2014 Unsatisfactory<\/strong><br>\n 3.5 mm\/s falls between the B\/C boundary (2.8) and C\/D boundary (7.1). This machine is not suitable for continuous long-term operation. Schedule a vibration analysis to identify the root cause \u2014 common faults at this level include unbalance, misalignment, or early bearing deterioration.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"example-box\">\n <div class=\"example-box-header\">Example 2: Commissioning a 500 kW Fan on Spring Isolators<\/div>\n <div class=\"example-box-body\">\n <p><strong>Machine:<\/strong> Centrifugal fan, 500 kW motor, 1480 RPM<\/p>\n <p><strong>Foundation:<\/strong> Steel frame on spring isolators (flexible foundation)<\/p>\n <p><strong>Classification:<\/strong> Group 3 (>300 kW, flexible foundation)<\/p>\n <p><strong>Measured vibration:<\/strong> 2.0 mm\/s RMS (highest reading, axial on drive-end bearing)<\/p>\n <p><strong>Group 3 boundaries:<\/strong> A\/B = 1.8 mm\/s \u00b7 B\/C = 4.5 mm\/s \u00b7 C\/D = 11.2 mm\/s<\/p>\n <div class=\"example-result\" style=\"background:var(--zone-b-bg);color:var(--zone-b);border:1px solid var(--zone-b-light);\">\n <strong>Result: Zone B \u2014 Satisfactory<\/strong><br>\n 2.0 mm\/s just exceeds the A\/B boundary (1.8). For a newly commissioned machine, this is acceptable but not ideal. The slight exceedance suggests investigating alignment or balance \u2014 a quick trim balance could bring it into Zone A and extend bearing life significantly.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"example-box\">\n <div class=\"example-box-header\">Example 3: Trending a 45 kW Motor on Rubber Mounts<\/div>\n <div class=\"example-box-body\">\n <p><strong>Machine:<\/strong> Electric motor, 45 kW, driving a small blower<\/p>\n <p><strong>Foundation:<\/strong> Rubber anti-vibration mounts (flexible foundation)<\/p>\n <p><strong>Classification:<\/strong> Group 4 (15\u2013300 kW, flexible foundation)<\/p>\n <p><strong>Baseline vibration:<\/strong> 3.0 mm\/s RMS (established 6 months ago)<\/p>\n <p><strong>Current vibration:<\/strong> 6.8 mm\/s RMS<\/p>\n <p><strong>Group 4 boundaries:<\/strong> A\/B = 2.8 mm\/s \u00b7 B\/C = 7.1 mm\/s \u00b7 C\/D = 18.0 mm\/s<\/p>\n <div class=\"example-result\" style=\"background:var(--zone-b-bg);color:var(--zone-b);border:1px solid var(--zone-b-light);\">\n <strong>Result: Zone B \u2014 but with a critical trend warning<\/strong><br>\n Although 6.8 mm\/s is technically still in Zone B for Group 4, the vibration has more than doubled from the 3.0 mm\/s baseline. This magnitude of change \u2014 even within the same zone \u2014 indicates a developing fault and warrants immediate investigation via spectral analysis. Do not wait for the reading to cross into Zone C.\n <\/div>\n <\/div>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: KEY CONCEPTS \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section section-alt\">\n <div class=\"container content\">\n <h2 class=\"section-title\">Key Concepts and Best Practices<\/h2>\n\n <div class=\"info-grid\">\n <div class=\"info-card\">\n <div class=\"info-card-icon blue\">\ud83c\udfaf<\/div>\n <h4>Actionable Limits<\/h4>\n <p>ISO 10816-3 translates the theoretical framework of Part 1 into concrete pass\/fail numbers. These values are the basis for setting alarm thresholds on online monitoring systems and for writing acceptance criteria into procurement contracts and overhaul specifications.<\/p>\n <\/div>\n <div class=\"info-card\">\n <div class=\"info-card-icon beige\">\ud83c\udfd7\ufe0f<\/div>\n <h4>Foundation Matters<\/h4>\n <p>A vibration level that is perfectly acceptable for a large, flexibly mounted fan (Group 3) could signal imminent failure for a medium-sized, rigidly mounted motor (Group 2). Misclassifying the foundation type is the most common error in applying this standard.<\/p>\n <\/div>\n <div class=\"info-card\">\n <div class=\"info-card-icon green\">\ud83d\udcc8<\/div>\n <h4>Trend Over Threshold<\/h4>\n <p>Experienced practitioners know that the trend is often more important than the absolute value. A machine running steadily at 2.5 mm\/s is a lower priority than one that jumped from 1.0 to 2.5 mm\/s in two weeks \u2014 even though both read the same number today.<\/p>\n <\/div>\n <div class=\"info-card\">\n <div class=\"info-card-icon orange\">\ud83d\udd0d<\/div>\n <h4>Screening, Not Diagnosis<\/h4>\n <p>This standard is a broadband screening tool. It identifies <em>that<\/em> a problem exists but not <em>what<\/em> the problem is. For root cause diagnosis, use <a href=\"https:\/\/vibromera.eu\/glossary\/spectral-analysis\/\">spectral analysis<\/a>, time waveform analysis, and phase measurements with a vibration analyzer.<\/p>\n <\/div>\n <\/div>\n\n <h3 class=\"subsection-title\">Setting Alarm Levels for Monitoring Systems<\/h3>\n <p>When configuring alarm levels on continuous or periodic vibration monitoring systems, the zone boundaries from ISO 10816-3 provide a natural framework. A common industrial practice is to set the \"Alert\" (or \"Warning\") alarm at the Zone B\/C boundary and the \"Danger\" (or \"Trip\") alarm at the Zone C\/D boundary. Some practitioners set a lower \"Caution\" level at the Zone A\/B boundary to flag early changes. For machines with established baselines, additional change-based alarms (e.g., \"alarm if vibration increases by more than 25% from baseline\") provide earlier detection of developing faults than absolute threshold alarms alone.<\/p>\n\n <h3 class=\"subsection-title\">Relationship to Other Standards<\/h3>\n <p>ISO 10816-3 is part of a comprehensive family of vibration evaluation standards. ISO 10816-1 provides the general principles. ISO 10816-7 covers rotodynamic pumps specifically. ISO 7919 addresses shaft vibration (measured on the rotating parts with proximity probes) rather than bearing housing vibration, and is primarily used for machines with fluid-film bearings such as turbines. The successor standard ISO 20816-3 (2022) harmonizes the housing vibration approach of 10816 with the shaft vibration approach of 7919 into a single unified framework. Understanding where ISO 10816-3 fits within this family is important for selecting the correct standard for each specific machine and measurement type.<\/p>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SECTION: FAQ \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"section\" id=\"faq\">\n <div class=\"container content\">\n <h2 class=\"section-title\">Frequently Asked Questions<\/h2>\n\n <div class=\"example-box\" style=\"margin-bottom:16px;\">\n <div class=\"example-box-header\">What vibration level is acceptable for a pump?<\/div>\n <div class=\"example-box-body\">\n <p>For a typical medium-sized pump (15\u2013300 kW) on a rigid foundation (Group 2), vibration up to 1.12 mm\/s RMS is excellent (Zone A), up to 2.8 mm\/s is acceptable for long-term operation (Zone B), up to 7.1 mm\/s requires investigation and corrective maintenance (Zone C), and above 7.1 mm\/s means immediate shutdown is recommended (Zone D). For pumps on flexible mounts, use Group 4 limits which are more lenient.<\/p>\n <\/div>\n <\/div>\n\n <div class=\"example-box\" style=\"margin-bottom:16px;\">\n <div class=\"example-box-header\">What is the difference between rigid and flexible foundations?<\/div>\n <div class=\"example-box-body\">\n <p>A rigid foundation (concrete pad, structural steel base) transmits vibration directly to the surrounding structure and requires lower vibration limits. A flexible foundation (spring isolators, rubber mounts, elastomeric pads) allows higher vibration at the machine because it isolates the vibration from the structure. The standard permits higher vibration limits for flexibly mounted machines because the isolation prevents the vibration from causing damage to surrounding equipment and structures.<\/p>\n <\/div>\n <\/div>\n\n <div class=\"example-box\" style=\"margin-bottom:16px;\">\n <div class=\"example-box-header\">Has ISO 10816-3 been replaced?<\/div>\n <div class=\"example-box-body\">\n <p>Yes, ISO 10816-3 has been formally superseded by ISO 20816-3 (published in 2022). However, the core zone boundary values remain highly relevant and are still the industry standard used in thousands of plants worldwide. Many existing monitoring systems, contractual specifications, and maintenance programs continue to reference ISO 10816-3 limits. The transition to ISO 20816-3 is gradual, and both standards can be used during this period.<\/p>\n <\/div>\n <\/div>\n\n <div class=\"example-box\">\n <div class=\"example-box-header\">Can I use this standard for machines below 15 kW?<\/div>\n <div class=\"example-box-body\">\n <p>ISO 10816-3 does not formally apply to machines below 15 kW. However, in practice many technicians use the Group 2 limits as a rough guideline for smaller equipment. For critical small machines, it is better to establish a baseline vibration level after installation and commissioning, then monitor for changes relative to that baseline rather than applying absolute limits from this standard.<\/p>\n <\/div>\n <\/div>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 FOOTER \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<section class=\"footer-section\">\n <div class=\"footer-inner\">\n <h2>Official ISO Standard<\/h2>\n <p>For the complete official standard with full measurement procedures and comprehensive guidance, visit: <a href=\"https:\/\/www.iso.org\/standard\/50528.html\" rel=\"nofollow noopener\" target=\"_blank\">ISO 10816-3 on ISO Store<\/a><\/p>\n <p style=\"font-size:12px;opacity:.6;margin-top:16px;\">The information presented above is a summary for educational purposes. For the full official standard, please purchase the complete document from ISO.<\/p>\n <a href=\"https:\/\/vibromera.eu\/glossary\/\" class=\"footer-link-back\">\u2190 Back to Main Glossary Index<\/a>\n <\/div>\n<\/section>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 JAVASCRIPT \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<script>\nconst LIMITS = {\n \/\/ [A\/B, B\/C, C\/D]\n group1: [0.71, 1.8, 4.5],\n group2: [1.12, 2.8, 7.1],\n group3: [1.8, 4.5, 11.2],\n group4: [2.8, 7.1, 18.0]\n};\n\nconst GROUP_NAMES = {\n group1: 'Group 1 \u2014 Large, Rigid Foundation (> 300 kW)',\n group2: 'Group 2 \u2014 Medium, Rigid Foundation (15\u2013300 kW)',\n group3: 'Group 3 \u2014 Large, Flexible Foundation (> 300 kW)',\n group4: 'Group 4 \u2014 Medium, Flexible Foundation (15\u2013300 kW)'\n};\n\nfunction getGroup(power, foundation) {\n if (power === 'large' && foundation === 'rigid') return 'group1';\n if (power === 'medium' && foundation === 'rigid') return 'group2';\n if (power === 'large' && foundation === 'flexible') return 'group3';\n return 'group4';\n}\n\nfunction evaluateVibration() {\n const power = document.getElementById('calc-power').value;\n const foundation = document.getElementById('calc-foundation').value;\n let vibration = parseFloat(document.getElementById('calc-vibration').value);\n const unit = document.getElementById('calc-unit').value;\n\n if (isNaN(vibration) || vibration < 0) {\n alert('Please enter a valid vibration value.');\n return;\n }\n\n \/\/ Convert in\/s to mm\/s\n let vibMM = unit === 'in' ? vibration * 25.4 : vibration;\n\n const groupKey = getGroup(power, foundation);\n const limits = LIMITS[groupKey];\n const groupName = GROUP_NAMES[groupKey];\n\n let zone, zoneName, zoneDesc, color, bgColor, barPct, barColor;\n\n if (vibMM <= limits[0]) {\n zone = 'A'; zoneName = 'Zone A \u2014 Good';\n zoneDesc = 'Vibration level typical of newly commissioned machines in excellent condition. No action required.';\n color = 'var(--zone-a)'; bgColor = 'var(--zone-a-bg)';\n barPct = Math.min((vibMM \/ limits[0]) * 25, 25);\n barColor = 'var(--zone-a)';\n } else if (vibMM <= limits[1]) {\n zone = 'B'; zoneName = 'Zone B \u2014 Satisfactory';\n zoneDesc = 'Acceptable for unrestricted long-term operation. Continue monitoring and trending.';\n color = 'var(--zone-b)'; bgColor = 'var(--zone-b-bg)';\n barPct = 25 + ((vibMM - limits[0]) \/ (limits[1] - limits[0])) * 25;\n barColor = 'var(--zone-b)';\n } else if (vibMM <= limits[2]) {\n zone = 'C'; zoneName = 'Zone C \u2014 Unsatisfactory';\n zoneDesc = 'Not suitable for continuous long-term operation. Investigate root cause and plan corrective maintenance. Schedule vibration analysis.';\n color = 'var(--zone-c)'; bgColor = 'var(--zone-c-bg)';\n barPct = 50 + ((vibMM - limits[1]) \/ (limits[2] - limits[1])) * 25;\n barColor = 'var(--zone-c)';\n } else {\n zone = 'D'; zoneName = 'Zone D \u2014 Unacceptable';\n zoneDesc = 'Danger of damage! Immediate shutdown and corrective action required. Operating in this zone risks catastrophic bearing or component failure.';\n color = 'var(--zone-d)'; bgColor = 'var(--zone-d-bg)';\n barPct = 75 + Math.min(((vibMM - limits[2]) \/ limits[2]) * 25, 25);\n barColor = 'var(--zone-d)';\n }\n\n const resultEl = document.getElementById('calc-result');\n resultEl.className = 'calc-result show';\n resultEl.style.background = bgColor;\n\n const vibDisplay = unit === 'in'\n ? vibration.toFixed(3) + ' in\/s (' + vibMM.toFixed(2) + ' mm\/s)'\n : vibration.toFixed(2) + ' mm\/s';\n\n resultEl.innerHTML = `\n <div class=\"calc-result-zone\" style=\"color:${color}\">Zone ${zone}<\/div>\n <div class=\"calc-result-label\" style=\"color:${color}\">${zoneName}<\/div>\n <div class=\"calc-result-desc\">${zoneDesc}<\/div>\n <div class=\"calc-result-bar\">\n <div class=\"calc-result-bar-fill\" style=\"width:${barPct}%;background:${barColor};\"><\/div>\n <\/div>\n <div class=\"calc-result-details\">\n <strong>Classification:<\/strong> ${groupName}<br>\n <strong>Measured value:<\/strong> ${vibDisplay}<br>\n <strong>Zone boundaries:<\/strong> A\/B = ${limits[0]} \u00b7 B\/C = ${limits[1]} \u00b7 C\/D = ${limits[2]} mm\/s\n <\/div>\n `;\n\n resultEl.scrollIntoView({ behavior: 'smooth', block: 'nearest' });\n}\n\n\/\/ Allow Enter key to trigger calculation\ndocument.getElementById('calc-vibration').addEventListener('keydown', function(e) {\n if (e.key === 'Enter') evaluateVibration();\n});\n\n\/\/ Sticky nav active state\nconst sections = document.querySelectorAll('section[id]');\nconst navLinks = document.querySelectorAll('.quick-nav a');\n\nwindow.addEventListener('scroll', () => {\n let current = '';\n sections.forEach(section => {\n const top = section.offsetTop - 100;\n if (window.scrollY >= top) {\n current = section.getAttribute('id');\n }\n });\n navLinks.forEach(link => {\n link.classList.remove('active');\n if (link.getAttribute('href') === '#' + current) {\n link.classList.add('active');\n }\n });\n});\n<\/script>\n\n<\/body>\n<\/html><\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>En oversikt over ISO 10816-3, den spesifikke standarden som angir grenseverdier for vibrasjonsalvorlighet og evalueringssoner for vanlige industrimaskiner som pumper, motorer og vifter.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[109,112],"tags":[],"class_list":["post-3","glossary","type-glossary","status-publish","hentry","category-glossary","category-iso-standards"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/glossary\/3","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/glossary"}],"about":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/types\/glossary"}],"version-history":[{"count":9,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/glossary\/3\/revisions"}],"predecessor-version":[{"id":101738,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/glossary\/3\/revisions\/101738"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/media?parent=3"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/categories?post=3"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/tags?post=3"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}