{"id":100275,"date":"2026-02-15T20:31:27","date_gmt":"2026-02-15T20:31:27","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100275"},"modified":"2026-07-16T01:09:42","modified_gmt":"2026-07-16T01:09:42","slug":"valve-leak-rate-iso5208","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/vi\/calculators\/valve-leak-rate-iso5208\/","title":{"rendered":"C\u00f4ng c\u1ee5 t\u00ednh to\u00e1n t\u1ef7 l\u1ec7 r\u00f2 r\u1ec9 van | Ti\u00eau chu\u1ea9n ISO 5208 Lo\u1ea1i A\u2013F"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Valve Leak Rate Calculator\",\"alternateName\":[\"ISO 5208 Calculator\",\"Valve Seat Leakage Calculator\",\"Valve Test Calculator\"],\"description\":\"Free online calculator for maximum allowable valve closure test leakage per ISO 5208:2015 Table 4. 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print{.vc-section-body{max-height:none!important}.vc-faq-a{max-height:none!important}.vc-results{max-height:none!important;padding:24px!important}.vc-copy-btn,.vc-section-chevron,.vc-faq-chevron,.vc-presets,.vc-promo{display:none!important}}\n<\/style>\n\n<div class=\"vc-calculator\" id=\"vc-valve-leak\">\n\n<header class=\"vc-header\">\n    <p class=\"vc-header-eyebrow\">Free Engineering Tool<\/p>\n    <h1 class=\"vc-header-title\">Valve Leak Rate Calculator<\/h1>\n    <p class=\"vc-header-subtitle\">Determine the maximum allowable closure test leakage per ISO 5208:2015 (Table 4) for leakage rates A through G. Evaluate pass\/fail based on measured leak rate for liquid and gas testing.<\/p>\n    <div class=\"vc-badges\">\n        <span class=\"vc-badge\">ISO 5208:2015<\/span>\n        <span class=\"vc-badge\">Rates A \u2013 G<\/span>\n        <span class=\"vc-badge\">Liquid &amp; Gas<\/span>\n    <\/div>\n<\/header>\n\n<div class=\"vc-card\">\n    <form class=\"vc-form\" id=\"vc-form\" autocomplete=\"off\">\n        <div class=\"vc-form-grid\">\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-dn\">Valve Size (DN) <span class=\"vc-label-hint\">(mm)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-dn\" inputmode=\"decimal\" step=\"any\" min=\"1\" placeholder=\"e.g. 100\" value=\"100\">\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-class\">Leakage Rate (ISO 5208:2015, Table 4)<\/label>\n                <select class=\"vc-select\" id=\"vc-class\">\n                    <option value=\"A\">Rate A \u2014 No visually detectable leakage<\/option>\n                    <option value=\"AA\">Rate AA \u2014 0.006 \u00d7 DN (liq) \/ 0.18 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                    <option value=\"B\">Rate B \u2014 0.01 \u00d7 DN (liq) \/ 0.3 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                    <option value=\"C\">Rate C \u2014 0.03 \u00d7 DN (liq) \/ 3 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                    <option value=\"CC\">Rate CC \u2014 0.08 \u00d7 DN (liq) \/ 22.3 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                    <option value=\"D\" selected>Rate D \u2014 0.1 \u00d7 DN (liq) \/ 30 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                    <option value=\"E\">Rate E \u2014 0.3 \u00d7 DN (liq) \/ 300 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                    <option value=\"EE\">Rate EE \u2014 0.39 \u00d7 DN (liq) \/ 470 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                    <option value=\"F\">Rate F \u2014 1 \u00d7 DN (liq) \/ 3000 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                    <option value=\"G\">Rate G \u2014 2 \u00d7 DN (liq) \/ 6000 \u00d7 DN (gas) mm\u00b3\/s<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-fluid\">Test Fluid<\/label>\n                <select class=\"vc-select\" id=\"vc-fluid\">\n                    <option value=\"liquid\" selected>Liquid (water)<\/option>\n                    <option value=\"gas\">Gas (air\/nitrogen)<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-measured\">Measured Leak Rate <span class=\"vc-label-hint\">(mm\u00b3\/s)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-measured\" inputmode=\"decimal\" step=\"any\" min=\"0\" placeholder=\"e.g. 2\" value=\"\">\n            <\/div>\n        <\/div>\n\n        <div class=\"vc-presets\">\n            <div class=\"vc-presets-label\">Quick presets<\/div>\n            <button type=\"button\" class=\"vc-preset-btn\" data-dn=\"50\" data-c=\"D\" data-f=\"liquid\">DN50 \/ Rate D \/ liquid<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-dn=\"150\" data-c=\"D\" data-f=\"liquid\">DN150 \/ Rate D \/ liquid<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-dn=\"200\" data-c=\"A\" data-f=\"gas\">DN200 \/ Rate A \/ gas<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-dn=\"100\" data-c=\"C\" data-f=\"liquid\">DN100 \/ Rate C \/ liquid<\/button>\n        <\/div>\n    <\/form>\n\n    <div class=\"vc-results\" id=\"vc-results\">\n        <div class=\"vc-results-head\">\n            <h2 class=\"vc-results-title\">Results<\/h2>\n            <button type=\"button\" class=\"vc-copy-btn\" id=\"vc-copy-btn\">\n                <svg width=\"14\" height=\"14\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg>\n                Copy\n            <\/button>\n        <\/div>\n        <div class=\"vc-result-grid\">\n            <div class=\"vc-rcard vc-rcard-primary\">\n                <div class=\"vc-rcard-label\">Maximum Permissible Leak Rate<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-max\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Leakage Rate Description<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-desc\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Recommended Test Duration<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-duration\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\" id=\"vc-r-verdict-card\">\n                <div class=\"vc-rcard-label\">Pass \/ Fail Evaluation<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-verdict\">\u2014<\/div>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Theory -->\n<div class=\"vc-section vc-open\" id=\"vc-sec-theory\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"true\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\ud83d\udcd8<\/span>\n            <span class=\"vc-section-title\">Theory &amp; Leakage Classes<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner vc-theory\">\n            <h3>ISO 5208:2015 Closure Test Leakage Rates<\/h3>\n            <p>ISO 5208:2015 (Table 4) defines ten closure test leakage rates \u2014 A, AA, B, C, CC, D, E, EE, F and G \u2014 for industrial valve testing. The maximum allowable leakage is directly proportional to the valve size DN and does <strong>not<\/strong> depend on the test pressure. The closure test pressure itself is fixed by the standard (see note below).<\/p>\n\n            <table class=\"vc-table\">\n                <thead><tr><th>Rate<\/th><th>Liquid (mm\u00b3\/s)<\/th><th>Liquid (drops\/s)<\/th><th>Gas (mm\u00b3\/s)<\/th><th>Gas (bubbles\/s)<\/th><\/tr><\/thead>\n                <tbody>\n                    <tr><td><strong>A<\/strong><\/td><td colspan=\"4\">No visually detectable leakage for the duration of the test<\/td><\/tr>\n                    <tr><td><strong>AA<\/strong><\/td><td>0.006 \u00d7 DN<\/td><td>0.0001 \u00d7 DN<\/td><td>0.18 \u00d7 DN<\/td><td>0.003 \u00d7 DN<\/td><\/tr>\n                    <tr><td><strong>B<\/strong><\/td><td>0.01 \u00d7 DN<\/td><td>0.00016 \u00d7 DN<\/td><td>0.3 \u00d7 DN<\/td><td>0.0046 \u00d7 DN<\/td><\/tr>\n                    <tr><td><strong>C<\/strong><\/td><td>0.03 \u00d7 DN<\/td><td>0.0005 \u00d7 DN<\/td><td>3 \u00d7 DN<\/td><td>0.0458 \u00d7 DN<\/td><\/tr>\n                    <tr><td><strong>CC<\/strong><\/td><td>0.08 \u00d7 DN<\/td><td>0.0013 \u00d7 DN<\/td><td>22.3 \u00d7 DN<\/td><td>0.3407 \u00d7 DN<\/td><\/tr>\n                    <tr><td><strong>D<\/strong><\/td><td>0.1 \u00d7 DN<\/td><td>0.0016 \u00d7 DN<\/td><td>30 \u00d7 DN<\/td><td>0.4584 \u00d7 DN<\/td><\/tr>\n                    <tr><td><strong>E<\/strong><\/td><td>0.3 \u00d7 DN<\/td><td>0.0048 \u00d7 DN<\/td><td>300 \u00d7 DN<\/td><td>4.5837 \u00d7 DN<\/td><\/tr>\n                    <tr><td><strong>EE<\/strong><\/td><td>0.39 \u00d7 DN<\/td><td>0.0062 \u00d7 DN<\/td><td>470 \u00d7 DN<\/td><td>7.1293 \u00d7 DN<\/td><\/tr>\n                    <tr><td><strong>F<\/strong><\/td><td>1 \u00d7 DN<\/td><td>0.016 \u00d7 DN<\/td><td>3000 \u00d7 DN<\/td><td>45.837 \u00d7 DN<\/td><\/tr>\n                    <tr><td><strong>G<\/strong><\/td><td>2 \u00d7 DN<\/td><td>0.032 \u00d7 DN<\/td><td>6000 \u00d7 DN<\/td><td>91.673 \u00d7 DN<\/td><\/tr>\n                <\/tbody>\n            <\/table>\n\n            <h3>Formulas<\/h3>\n            <p>For <strong>liquid<\/strong> testing (water), the maximum allowable leakage in mm\u00b3\/s:<\/p>\n            <div class=\"vc-formula-box\" id=\"vc-katex-1\"><\/div>\n            <p>For <strong>gas<\/strong> testing (air\/N\u2082), the maximum allowable leakage in mm\u00b3\/s (or bubbles\/s):<\/p>\n            <div class=\"vc-formula-box\" id=\"vc-katex-2\"><\/div>\n            <p>where q<sub>L<\/sub> and q<sub>G<\/sub> are the unit leakage rates from Table 4 above (e.g. 0.1 mm\u00b3\/s per DN for Rate D, liquid) and DN is the nominal valve size. 1 mm\u00b3\/s = 0.06 ml\/min.<\/p>\n\n            <h3>Practical Example<\/h3>\n            <div class=\"vc-example-box\">\n                <div class=\"vc-example-title\">Example \u2014 DN100 Gate Valve, Rate D, Liquid Test<\/div>\n                <p><strong>Given:<\/strong> DN = 100 mm, leakage Rate D, liquid test<\/p>\n                <p>Q<sub>max<\/sub> = 0.1 \u00d7 100 = <strong>10 mm\u00b3\/s<\/strong> (= 0.6 ml\/min, \u2248 0.16 drops\/s)<\/p>\n                <p>If measured leak = 2 mm\u00b3\/s \u2192 <strong>PASS<\/strong> (within limit)<\/p>\n            <\/div>\n\n            <div class=\"vc-info-box\">\n                <p><strong>\u2139\ufe0f Test Duration (ISO 5208:2015, Table 2, closure test):<\/strong> DN \u2264 50: 15 s, DN 65\u2013150: 60 s, DN \u2265 200: 120 s (isolation valves). For check valves the minimum closure test duration is 60 s up to DN 150 and 120 s for DN \u2265 200.<\/p>\n            <\/div>\n\n            <div class=\"vc-info-box\">\n                <p><strong>\u2139\ufe0f Test Pressure:<\/strong> The closure test pressure is set by ISO 5208, not chosen freely: at least 1.1 \u00d7 CWP for liquid testing, and 1.1 \u00d7 CWP or 6 bar \u00b1 1 bar for gas testing. The Table 4 allowable leakage does not vary with the applied pressure.<\/p>\n            <\/div>\n\n            <div class=\"vc-warning-box\">\n                <p style=\"margin:0;font-size:14px;color:var(--vc-ink-secondary);\"><strong>\u26a0\ufe0f Note:<\/strong> Rate A does not mean mathematically zero \u2014 it means no visually detectable leakage during the specified test duration. Rates A, B, C, D, E, F and G correspond to the leakage values of EN 12266-1; API 598 acceptance values correspond to Rate A (DN \u2264 50), Rate AA (gas) and Rate CC (liquid) for other than metal-seated check valves, and to Rate EE (gas) \/ Rate G (liquid) for check valves (ISO 5208:2015, Table 4, Note 4).<\/p>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Related -->\n<div class=\"vc-section\" id=\"vc-sec-related\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\ud83d\udd17<\/span>\n            <span class=\"vc-section-title\">Related Calculators<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner\">\n            <div class=\"vc-related\">\n                <a class=\"vc-related-link\" href=\"\/calculators\/flange-rating-lookup\/\">Flange Rating Lookup<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/pressure-vessel-en13445\/\">Pressure Vessel (EN 13445)<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/pipe-flexibility-calculator\/\">Pipe Flexibility Calculator<\/a>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- FAQ -->\n<div class=\"vc-section\" id=\"vc-sec-faq\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\u2753<\/span>\n            <span class=\"vc-section-title\">Frequently Asked Questions<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner\">\n            <div class=\"vc-faq-list\" id=\"vc-faq-list\"><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<div class=\"vc-promo\">\n    <div class=\"vc-promo-text\">\n        <strong>Vibromera \u2014 Portable Balancing &amp; Vibration Analysis<\/strong><br>\n        Professional instruments for vibration diagnostics and field balancing. Used in 50+ countries.\n    <\/div>\n    <a class=\"vc-promo-link\" href=\"https:\/\/vibromera.eu\/\" target=\"_blank\" rel=\"noopener\">Learn More<\/a>\n<\/div>\n\n<footer class=\"vc-footer\">\n    <p>\u00a9 2024\u20132025 <a href=\"https:\/\/vibromera.eu\/\">Vibromera<\/a> \u2014 Engineering Calculators<\/p>\n    <p style=\"font-size:12px;margin-top:4px;\">Based on ISO 5208:2015 (Industrial valves \u2014 Pressure testing of metallic valves), Tables 2 and 4. Last updated: July 2026<\/p>\n    <div class=\"vc-footer-links\">\n        <a href=\"\/calculators\/engineering-calculators\/\">All Calculators<\/a>\n        <a href=\"https:\/\/vibromera.eu\/contacts\/\">Contact<\/a>\n    <\/div>\n<\/footer>\n\n<\/div>\n\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/katex@0.16.11\/dist\/katex.min.js\"><\/script>\n<script>\n(function(){\n    'use strict';\n    function $(id){ return document.getElementById(id); }\n    function fmt(n,d){ if(isNaN(n)||!isFinite(n)) return '\u2014'; var f=n.toFixed(d===undefined?2:d); return f.replace(\/(\\.\\d*?)0+$\/,'$1').replace(\/\\.$\/,''); }\n\n    \/\/ ISO 5208:2015 Table 4 unit leakage rates (per DN):\n    \/\/ liq\/gas in mm3\/s, drops in drops\/s, bub in bubbles\/s\n    var rates = {\n        A:  { liq: 0,     drops: 0,       gas: 0,    bub: 0,      desc: 'No visually detectable leakage' },\n        AA: { liq: 0.006, drops: 0.0001,  gas: 0.18, bub: 0.003,  desc: 'Rate AA \u2014 very tight closure' },\n        B:  { liq: 0.01,  drops: 0.00016, gas: 0.3,  bub: 0.0046, desc: 'Rate B \u2014 tight closure' },\n        C:  { liq: 0.03,  drops: 0.0005,  gas: 3,    bub: 0.0458, desc: 'Rate C \u2014 stringent process valves' },\n        CC: { liq: 0.08,  drops: 0.0013,  gas: 22.3, bub: 0.3407, desc: 'Rate CC \u2014 resilient\/soft-seated ref.' },\n        D:  { liq: 0.1,   drops: 0.0016,  gas: 30,   bub: 0.4584, desc: 'Rate D \u2014 common industrial rate' },\n        E:  { liq: 0.3,   drops: 0.0048,  gas: 300,  bub: 4.5837, desc: 'Rate E \u2014 less critical services' },\n        EE: { liq: 0.39,  drops: 0.0062,  gas: 470,  bub: 7.1293, desc: 'Rate EE \u2014 check-valve ref. (gas)' },\n        F:  { liq: 1,     drops: 0.016,   gas: 3000, bub: 45.837, desc: 'Rate F \u2014 coarse closure' },\n        G:  { liq: 2,     drops: 0.032,   gas: 6000, bub: 91.673, desc: 'Rate G \u2014 coarsest tabulated rate' }\n    };\n\n    \/\/ Minimum closure test duration by DN, seconds (ISO 5208:2015 Table 2, isolation valves)\n    function getTestDuration(dn) {\n        if (dn <= 50) return 15;\n        if (dn <= 150) return 60;\n        return 120;\n    }\n\n    function calculate() {\n        var dn = parseFloat($('vc-dn').value);\n        var cls = $('vc-class').value;\n        var fluid = $('vc-fluid').value;\n        var measured = parseFloat($('vc-measured').value);\n\n        if (!dn || dn <= 0) {\n            $('vc-results').classList.remove('vc-visible');\n            return;\n        }\n\n        var rate = rates[cls];\n        var k = fluid === 'liquid' ? rate.liq : rate.gas;\n        var kAlt = fluid === 'liquid' ? rate.drops : rate.bub;\n        var altUnit = fluid === 'liquid' ? 'drops\/s' : 'bubbles\/s';\n        var qMax = k * dn;\n        var qAlt = kAlt * dn;\n\n        \/\/ Display\n        if (cls === 'A') {\n            $('vc-r-max').innerHTML = '<span style=\"color:var(--vc-green)\">ZERO<\/span> <span class=\"vc-rcard-unit\">(no visually detectable leakage)<\/span>';\n        } else {\n            $('vc-r-max').innerHTML = fmt(qMax, qMax < 1 ? 4 : 2) + ' <span class=\"vc-rcard-unit\">mm\u00b3\/s<\/span> <span class=\"vc-rcard-unit\">(= ' + fmt(qMax * 0.06, 3) + ' ml\/min, ' + fmt(qAlt, qAlt < 1 ? 4 : 2) + ' ' + altUnit + ')<\/span>';\n        }\n\n        $('vc-r-desc').innerHTML = '<span style=\"font-size:16px\">' + rate.desc + '<\/span>';\n\n        var recDur = getTestDuration(dn);\n        $('vc-r-duration').innerHTML = recDur + ' <span class=\"vc-rcard-unit\">seconds<\/span> <span class=\"vc-rcard-unit\">(for DN ' + dn + ', isolation valves)<\/span>';\n\n        \/\/ Pass\/Fail\n        var card = $('vc-r-verdict-card');\n        card.className = 'vc-rcard';\n        if (!isNaN(measured) && measured >= 0) {\n            if (cls === 'A') {\n                if (measured === 0) {\n                    $('vc-r-verdict').innerHTML = '<span style=\"color:var(--vc-green);font-size:28px;\">\u2713 PASS<\/span>';\n                    card.className = 'vc-rcard vc-rcard-pass';\n                } else {\n                    $('vc-r-verdict').innerHTML = '<span style=\"color:var(--vc-red);font-size:28px;\">\u2717 FAIL<\/span> <span class=\"vc-rcard-unit\">(any detectable leak = fail)<\/span>';\n                    card.className = 'vc-rcard vc-rcard-fail';\n                }\n            } else {\n                if (measured <= qMax) {\n                    $('vc-r-verdict').innerHTML = '<span style=\"color:var(--vc-green);font-size:28px;\">\u2713 PASS<\/span> <span class=\"vc-rcard-unit\">(' + fmt(measured,2) + ' \u2264 ' + fmt(qMax,2) + ' mm\u00b3\/s)<\/span>';\n                    card.className = 'vc-rcard vc-rcard-pass';\n                } else {\n                    $('vc-r-verdict').innerHTML = '<span style=\"color:var(--vc-red);font-size:28px;\">\u2717 FAIL<\/span> <span class=\"vc-rcard-unit\">(' + fmt(measured,2) + ' > ' + fmt(qMax,2) + ' mm\u00b3\/s)<\/span>';\n                    card.className = 'vc-rcard vc-rcard-fail';\n                }\n            }\n        } else {\n            $('vc-r-verdict').innerHTML = '<span class=\"vc-rcard-unit\">Enter measured leak rate above<\/span>';\n        }\n\n        $('vc-results').classList.add('vc-visible');\n    }\n\n    \/* \u2500\u2500 PRESETS \u2500\u2500 *\/\n    document.querySelectorAll('.vc-preset-btn').forEach(function(btn){\n        btn.addEventListener('click', function(e){\n            e.preventDefault();\n            $('vc-dn').value = this.getAttribute('data-dn');\n            $('vc-class').value = this.getAttribute('data-c');\n            $('vc-fluid').value = this.getAttribute('data-f');\n            calculate();\n        });\n    });\n\n    $('vc-form').addEventListener('input', calculate);\n    $('vc-form').addEventListener('change', calculate);\n\n    \/* \u2500\u2500 COPY \u2500\u2500 *\/\n    $('vc-copy-btn').addEventListener('click', function(){\n        var text = 'Valve Leak Rate Calculation (ISO 5208:2015, Table 4)\\n\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\n' +\n            'DN: ' + $('vc-dn').value + ' mm\\n' +\n            'Leakage Rate: ' + $('vc-class').value + '\\n' +\n            'Fluid: ' + $('vc-fluid').options[$('vc-fluid').selectedIndex].text + '\\n' +\n            'Max Leak Rate: ' + $('vc-r-max').textContent + '\\n' +\n            'Verdict: ' + $('vc-r-verdict').textContent + '\\n' +\n            '\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\nvibromera.eu\/calculators\/valve-leak-rate-iso5208\/';\n        if(navigator.clipboard){\n            navigator.clipboard.writeText(text).then(function(){\n                var btn=$('vc-copy-btn'); btn.classList.add('vc-copied');\n                btn.innerHTML='<svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><polyline points=\"20 6 9 17 4 12\"\/><\/svg> Copied!';\n                setTimeout(function(){ btn.classList.remove('vc-copied'); btn.innerHTML='<svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg> Copy'; },2000);\n            });\n        }\n    });\n\n    \/* \u2500\u2500 SECTIONS \u2500\u2500 *\/\n    document.querySelectorAll('.vc-section-toggle').forEach(function(btn){\n        btn.addEventListener('click', function(){\n            var s=this.closest('.vc-section'); s.classList.toggle('vc-open');\n            this.setAttribute('aria-expanded', s.classList.contains('vc-open'));\n        });\n    });\n\n    \/* \u2500\u2500 FAQ \u2500\u2500 *\/\n    var faqData = [\n        { q:'What is ISO 5208?', a:'<p>ISO 5208:2015 (Industrial valves \u2014 Pressure testing of metallic valves) defines the requirements for pressure testing of industrial valves, including shell and closure (seat) tests. Table 4 of the standard specifies ten closure test leakage rates \u2014 A, AA, B, C, CC, D, E, EE, F and G \u2014 with defined acceptance criteria.<\/p>' },\n        { q:'What is the difference between Rate A and Rate D?', a:'<p><strong>Rate A<\/strong> requires no visually detectable leakage for the duration of the test \u2014 the most stringent requirement, used for critical services (toxic, flammable fluids). <strong>Rate D<\/strong> allows a leakage of 0.1 \u00d7 DN mm\u00b3\/s for liquid or 30 \u00d7 DN mm\u00b3\/s for gas \u2014 a commonly specified industrial rate for general process applications.<\/p>' },\n        { q:'Does the allowable leak rate depend on test pressure?', a:'<p>No. In ISO 5208:2015 Table 4 the maximum allowable closure test leakage is directly proportional to the valve size DN only (e.g. Rate D liquid = 0.1 \u00d7 DN mm\u00b3\/s). The test pressure is prescribed separately by the standard: at least 1.1 \u00d7 CWP for liquid closure tests, and 1.1 \u00d7 CWP or 6 bar \u00b1 1 bar for gas closure tests.<\/p>' },\n        { q:'What is the difference between ISO 5208 and API 598 \/ EN 12266?', a:'<p>All three cover valve pressure testing. ISO 5208:2015 defines ten leakage rates (A\u2013G, including AA, CC, EE); its Rates A, B, C, D, E, F and G correspond to the leakage values of EN 12266-1. API 598 acceptance values correspond to ISO 5208 Rate A (DN \u2264 50), Rate AA (gas) and Rate CC (liquid) for most valves, and Rate EE (gas) \/ Rate G (liquid) for check valves. API 598 is widely used in North America, ISO 5208 internationally.<\/p>' },\n        { q:'Can gas and liquid leak rates be compared?', a:'<p>Not directly. Both are tabulated in mm\u00b3\/s, but for the same rate designation the gas value is much larger (e.g. Rate D: 0.1 \u00d7 DN mm\u00b3\/s liquid vs 30 \u00d7 DN mm\u00b3\/s gas) because gas has far lower viscosity. In practice liquid leakage is often counted in drops\/s and gas leakage in bubbles\/s \u2014 ISO 5208 Table 4 tabulates both sets of units.<\/p>' }\n    ];\n    var faqList = $('vc-faq-list');\n    faqData.forEach(function(faq){ faqList.innerHTML += '<div class=\"vc-faq-item\"><button type=\"button\" class=\"vc-faq-q\"><span>'+faq.q+'<\/span><svg class=\"vc-faq-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button><div class=\"vc-faq-a\"><div class=\"vc-faq-a-inner\">'+faq.a+'<\/div><\/div><\/div>'; });\n    faqList.addEventListener('click', function(e){ var btn=e.target.closest('.vc-faq-q'); if(btn) btn.closest('.vc-faq-item').classList.toggle('vc-open'); });\n\n    \/* \u2500\u2500 KATEX \u2500\u2500 *\/\n    function renderFormulas(){\n        try{\n            katex.render('Q_{\\\\text{liquid}} = q_L \\\\times DN \\\\quad [\\\\text{mm}^3\/\\\\text{s}]', $('vc-katex-1'), {displayMode:true,throwOnError:false});\n            katex.render('Q_{\\\\text{gas}} = q_G \\\\times DN \\\\quad [\\\\text{mm}^3\/\\\\text{s}]', $('vc-katex-2'), {displayMode:true,throwOnError:false});\n        }catch(e){}\n    }\n\n    function init(){\n        renderFormulas();\n        calculate();\n    }\n    if(document.readyState==='loading') document.addEventListener('DOMContentLoaded',init); else init();\n})();\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>C\u00f4ng c\u1ee5 t\u00ednh to\u00e1n tr\u1ef1c tuy\u1ebfn mi\u1ec5n ph\u00ed t\u1ef7 l\u1ec7 r\u00f2 r\u1ec9 van theo ti\u00eau chu\u1ea9n ISO 5208. X\u00e1c \u0111\u1ecbnh m\u1ee9c r\u00f2 r\u1ec9 t\u1ed1i \u0111a cho ph\u00e9p \u0111\u1ed1i v\u1edbi c\u00e1c lo\u1ea1i r\u00f2 r\u1ec9 m\u1eb7t b\u00edch van t\u1eeb A \u0111\u1ebfn F. \u0110\u00e1nh gi\u00e1 k\u1ebft qu\u1ea3 \u0111\u1ea1t\/kh\u00f4ng \u0111\u1ea1t \u0111\u1ed1i v\u1edbi th\u1eed nghi\u1ec7m ch\u1ea5t l\u1ecfng v\u00e0 kh\u00ed.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100275","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/vi\/wp-json\/wp\/v2\/calculator\/100275","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/vi\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/vi\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":4,"href":"https:\/\/vibromera.eu\/vi\/wp-json\/wp\/v2\/calculator\/100275\/revisions"}],"predecessor-version":[{"id":102617,"href":"https:\/\/vibromera.eu\/vi\/wp-json\/wp\/v2\/calculator\/100275\/revisions\/102617"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/vi\/wp-json\/wp\/v2\/media?parent=100275"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/vi\/wp-json\/wp\/v2\/categories?post=100275"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/vi\/wp-json\/wp\/v2\/tags?post=100275"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}