{"id":4843,"date":"2026-07-08T16:44:17","date_gmt":"2026-07-08T08:44:17","guid":{"rendered":"https:\/\/wanantec.com\/tank-vent-sizing-calculator\/"},"modified":"2026-07-08T16:44:17","modified_gmt":"2026-07-08T08:44:17","slug":"tank-vent-sizing-calculator","status":"publish","type":"page","link":"https:\/\/wanantec.com\/zh\/tank-vent-sizing-calculator\/","title":{"rendered":"API 2000 Tank Vent Sizing Calculator"},"content":{"rendered":"<div class=\"wanan-calculator-page\">\n\n<h2>API 2000 Storage Tank Vent Sizing Calculator<\/h2>\n\n<p>Use this calculator to estimate the required venting capacity for atmospheric storage tanks based on <strong>API 2000 7th Edition<\/strong>. Enter your tank parameters below to determine normal inbreathing, normal outbreathing, and emergency venting requirements.<\/p>\n\n<div class=\"wanan-calc-disclaimer\" style=\"background:#fff3cd;border-left:4px solid #ffc107;padding:12px 16px;margin:16px 0;border-radius:0 4px 4px 0;font-size:0.9em;\">\n<strong>Disclaimer:<\/strong> This calculator provides preliminary estimates for reference only. Actual vent sizing must be performed by a qualified engineer following the complete API 2000 standard, considering all site-specific conditions. Wanan Technology is not liable for decisions based solely on these estimates.\n<\/div>\n\n<h3>Step 1: Enter Tank Parameters<\/h3>\n\n<div class=\"wanan-calc-form\" style=\"background:#f8f9fa;padding:24px;border-radius:8px;margin:16px 0;\">\n\n<div style=\"display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:16px;\">\n\n<div>\n<label for=\"tankCapacity\" style=\"display:block;font-weight:600;margin-bottom:4px;\">Tank Capacity (barrels) *<\/label>\n<input type=\"number\" id=\"tankCapacity\" value=\"20000\" min=\"100\" max=\"500000\" style=\"width:100%;padding:8px 12px;border:1px solid #ccc;border-radius:4px;font-size:14px;\" \/>\n<\/div>\n\n<div>\n<label for=\"tankDiameter\" style=\"display:block;font-weight:600;margin-bottom:4px;\">Tank Diameter (feet) *<\/label>\n<input type=\"number\" id=\"tankDiameter\" value=\"100\" min=\"5\" max=\"400\" step=\"0.1\" style=\"width:100%;padding:8px 12px;border:1px solid #ccc;border-radius:4px;font-size:14px;\" \/>\n<\/div>\n\n<div>\n<label for=\"tankHeight\" style=\"display:block;font-weight:600;margin-bottom:4px;\">Liquid Height (feet) *<\/label>\n<input type=\"number\" id=\"tankHeight\" value=\"40\" min=\"2\" max=\"100\" step=\"0.1\" style=\"width:100%;padding:8px 12px;border:1px solid #ccc;border-radius:4px;font-size:14px;\" \/>\n<\/div>\n\n<div>\n<label for=\"productType\" style=\"display:block;font-weight:600;margin-bottom:4px;\">Stored Product *<\/label>\n<select id=\"productType\" style=\"width:100%;padding:8px 12px;border:1px solid #ccc;border-radius:4px;font-size:14px;\">\n<option value=\"crude\">Crude Oil (volatile)<\/option>\n<option value=\"gasoline\">Gasoline (volatile)<\/option>\n<option value=\"naphtha\">Naphtha (volatile)<\/option>\n<option value=\"diesel\">Diesel (non-volatile)<\/option>\n<option value=\"jetfuel\">Jet Fuel (non-volatile)<\/option>\n<option value=\"water\">Water \/ Non-flammable<\/option>\n<\/select>\n<\/div>\n\n<div>\n<label for=\"pumpInRate\" style=\"display:block;font-weight:600;margin-bottom:4px;\">Max Pump-In Rate (GPM)<\/label>\n<input type=\"number\" id=\"pumpInRate\" value=\"500\" min=\"0\" max=\"10000\" style=\"width:100%;padding:8px 12px;border:1px solid #ccc;border-radius:4px;font-size:14px;\" \/>\n<\/div>\n\n<div>\n<label for=\"pumpOutRate\" style=\"display:block;font-weight:600;margin-bottom:4px;\">Max Pump-Out Rate (GPM)<\/label>\n<input type=\"number\" id=\"pumpOutRate\" value=\"500\" min=\"0\" max=\"10000\" style=\"width:100%;padding:8px 12px;border:1px solid #ccc;border-radius:4px;font-size:14px;\" \/>\n<\/div>\n\n<div>\n<label for=\"insulation\" style=\"display:block;font-weight:600;margin-bottom:4px;\">Tank Insulation (fire exposure)<\/label>\n<select id=\"insulation\" style=\"width:100%;padding:8px 12px;border:1px solid #ccc;border-radius:4px;font-size:14px;\">\n<option value=\"0.3\">Insulated (F=0.3)<\/option>\n<option value=\"1.0\" selected>Uninsulated (F=1.0)<\/option>\n<option value=\"0\">Underground \/ Bunded (F=0)<\/option>\n<\/select>\n<\/div>\n\n<\/div>\n\n<div style=\"margin-top:16px;\">\n<button onclick=\"calculateVenting()\" style=\"background:#1a73e8;color:#fff;padding:12px 32px;border:none;border-radius:4px;font-size:16px;font-weight:bold;cursor:pointer;\">Calculate Venting Requirements<\/button>\n<button onclick=\"resetCalculator()\" style=\"background:#fff;color:#666;padding:12px 24px;border:1px solid #ccc;border-radius:4px;font-size:14px;margin-left:8px;cursor:pointer;\">Reset<\/button>\n<\/div>\n\n<\/div>\n\n<h3>Step 2: Results<\/h3>\n\n<div id=\"calcResults\" style=\"display:none;\">\n\n<div style=\"display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:16px;margin:16px 0;\">\n\n<div style=\"background:#e8f5e9;border:1px solid #4caf50;border-radius:8px;padding:20px;\">\n<h4 style=\"margin:0 0 12px 0;color:#2e7d32;\">Normal Inbreathing (Vacuum)<\/h4>\n<p style=\"font-size:0.85em;color:#555;margin:0 0 8px 0;\">Required when liquid is pumped out or temperature drops<\/p>\n<table style=\"width:100%;font-size:0.9em;\">\n<tr><td style=\"padding:4px 0;color:#666;\">Thermal Inbreathing:<\/td><td style=\"text-align:right;font-weight:600;\" id=\"thermalIn\">&#8212;<\/td><\/tr>\n<tr><td style=\"padding:4px 0;color:#666;\">Pump-Out Inbreathing:<\/td><td style=\"text-align:right;font-weight:600;\" id=\"pumpOutIn\">&#8212;<\/td><\/tr>\n<tr style=\"border-top:2px solid #4caf50;\"><td style=\"padding:8px 0;font-weight:bold;color:#2e7d32;\">Total Inbreathing:<\/td><td style=\"text-align:right;font-weight:bold;font-size:1.1em;color:#2e7d32;\" id=\"totalIn\">&#8212;<\/td><\/tr>\n<\/table>\n<\/div>\n\n<div style=\"background:#fff3e0;border:1px solid #ff9800;border-radius:8px;padding:20px;\">\n<h4 style=\"margin:0 0 12px 0;color:#e65100;\">Normal Outbreathing (Pressure)<\/h4>\n<p style=\"font-size:0.85em;color:#555;margin:0 0 8px 0;\">Required when liquid is pumped in or temperature rises<\/p>\n<table style=\"width:100%;font-size:0.9em;\">\n<tr><td style=\"padding:4px 0;color:#666;\">Thermal Outbreathing:<\/td><td style=\"text-align:right;font-weight:600;\" id=\"thermalOut\">&#8212;<\/td><\/tr>\n<tr><td style=\"padding:4px 0;color:#666;\">Pump-In Outbreathing:<\/td><td style=\"text-align:right;font-weight:600;\" id=\"pumpInOut\">&#8212;<\/td><\/tr>\n<tr style=\"border-top:2px solid #ff9800;\"><td style=\"padding:8px 0;font-weight:bold;color:#e65100;\">Total Outbreathing:<\/td><td style=\"text-align:right;font-weight:bold;font-size:1.1em;color:#e65100;\" id=\"totalOut\">&#8212;<\/td><\/tr>\n<\/table>\n<\/div>\n\n<div style=\"background:#ffebee;border:1px solid #f44336;border-radius:8px;padding:20px;\">\n<h4 style=\"margin:0 0 12px 0;color:#c62828;\">Emergency Venting (Fire)<\/h4>\n<p style=\"font-size:0.85em;color:#555;margin:0 0 8px 0;\">Required for fire exposure scenario per API 2000<\/p>\n<table style=\"width:100%;font-size:0.9em;\">\n<tr><td style=\"padding:4px 0;color:#666;\">Wetted Surface Area:<\/td><td style=\"text-align:right;font-weight:600;\" id=\"wettedArea\">&#8212;<\/td><\/tr>\n<tr><td style=\"padding:4px 0;color:#666;\">Environmental Factor:<\/td><td style=\"text-align:right;font-weight:600;\" id=\"envFactor\">&#8212;<\/td><\/tr>\n<tr style=\"border-top:2px solid #f44336;\"><td style=\"padding:8px 0;font-weight:bold;color:#c62828;\">Emergency Capacity:<\/td><td style=\"text-align:right;font-weight:bold;font-size:1.1em;color:#c62828;\" id=\"emergencyVent\">&#8212;<\/td><\/tr>\n<\/table>\n<\/div>\n\n<\/div>\n\n<h3>Step 3: Equipment Recommendations<\/h3>\n\n<div style=\"background:#e3f2fd;border:1px solid #2196f3;border-radius:8px;padding:20px;margin:16px 0;\">\n<table style=\"width:100%;font-size:0.95em;\">\n<tr><td style=\"padding:8px 0;font-weight:600;color:#1565c0;\">Recommended PVRV Size:<\/td><td id=\"pvrvSize\" style=\"text-align:right;font-weight:600;\">&#8212;<\/td><\/tr>\n<tr><td style=\"padding:8px 0;font-weight:600;color:#1565c0;\">Recommended Flame Arrestor:<\/td><td id=\"faSize\" style=\"text-align:right;font-weight:600;\">&#8212;<\/td><\/tr>\n<tr><td style=\"padding:8px 0;font-weight:600;color:#1565c0;\">Emergency Vent (Manway):<\/td><td id=\"ervSize\" style=\"text-align:right;font-weight:600;\">&#8212;<\/td><\/tr>\n<\/table>\n<p style=\"margin:16px 0 0 0;font-size:0.85em;color:#666;\">Recommendations are based on the calculated venting requirements and standard nozzle sizes. Actual sizing should account for piping configuration, back pressure, and set pressure margins.<\/p>\n<\/div>\n\n<div style=\"background:#f8f9fa;border-radius:8px;padding:20px;margin:16px 0;text-align:center;\">\n<p style=\"margin:0 0 12px 0;font-size:1.05em;color:#333;\">Need a detailed vent sizing report for your tank?<\/p>\n<a href=\"https:\/\/wanantec.com\/contact-us\/\" style=\"display:inline-block;background:#1a73e8;color:#fff;padding:12px 32px;text-decoration:none;border-radius:4px;font-weight:bold;\">Request Engineering Consultation<\/a>\n<\/div>\n\n<\/div>\n\n<h2>How API 2000 Vent Sizing Works<\/h2>\n\n<p>API 2000 is the primary international standard for atmospheric and low-pressure storage tank venting. It defines three categories of venting requirements:<\/p>\n\n<h3>Normal Inbreathing (Vacuum Protection)<\/h3>\n<p>When liquid is pumped out of a tank, the vapor space above the liquid expands and pressure drops. Without adequate venting, this vacuum can cause tank implosion. The total inbreathing requirement is the sum of:<\/p>\n<ul>\n<li><strong>Thermal Inbreathing:<\/strong> Caused by temperature drops (day-to-night transition, rainstorm on hot tank roof). API 2000 Table 1 provides values based on tank capacity.<\/li>\n<li><strong>Liquid Displacement (Pump-Out):<\/strong> Equal to the maximum pump-out rate converted to air equivalent. API 2000 specifies 5.6 SCFH per GPM (or 0.94 Nm3\/h per m3\/h) of pump-out capacity.<\/li>\n<\/ul>\n\n<h3>Normal Outbreathing (Pressure Relief)<\/h3>\n<p>When liquid is pumped into a tank or temperature rises, vapor is compressed and pressure increases. The total outbreathing requirement is the sum of:<\/p>\n<ul>\n<li><strong>Thermal Outbreathing:<\/strong> Caused by temperature rise. For volatile fluids, API 2000 specifies higher thermal outbreathing than for non-volatile fluids.<\/li>\n<li><strong>Liquid Displacement (Pump-In):<\/strong> For volatile fluids, API 2000 specifies 2.0 SCFH per GPM. For non-volatile fluids, 1.0 SCFH per GPM.<\/li>\n<\/ul>\n\n<h3>Emergency Venting (Fire Exposure)<\/h3>\n<p>If a tank is exposed to external fire, the liquid absorbs heat and vaporizes rapidly, creating massive pressure. Emergency venting capacity is calculated based on:<\/p>\n<ul>\n<li><strong>Wetted Surface Area:<\/strong> The area of tank shell in contact with liquid up to 30 feet above grade.<\/li>\n<li><strong>Environmental Factor (F):<\/strong> 1.0 for uninsulated tanks, 0.3 for insulated tanks, 0 for underground\/bunded tanks.<\/li>\n<li><strong>Latent Heat &#038; Molecular Weight:<\/strong> Product-specific properties affecting vaporization rate.<\/li>\n<\/ul>\n\n<h2>Frequently Asked Questions<\/h2>\n\n<div class=\"wanan-faq-list\">\n\n<div class=\"wanan-faq-item\">\n<h3 class=\"wanan-faq-q\">What is API 2000 and which edition should I use?<\/h3>\n<p class=\"wanan-faq-a\">API 2000 is the American Petroleum Institute standard for venting atmospheric and low-pressure storage tanks. The 7th Edition (2014, reaffirmed 2020) is the current version. It significantly revised thermal inbreathing requirements from the 6th Edition, generally increasing the required capacity. Most jurisdictions and insurance underwriters now require compliance with the 7th Edition.<\/p>\n<\/div>\n\n<div class=\"wanan-faq-item\">\n<h3 class=\"wanan-faq-q\">Do all storage tanks need both normal and emergency venting?<\/h3>\n<p class=\"wanan-faq-a\">All atmospheric storage tanks require normal venting (inbreathing and outbreathing). Emergency venting is required for tanks storing flammable liquids with flash points below 200 F (93 C) that could be exposed to fire. Tanks storing non-flammable liquids (e.g., water, fire-fighting foam) may not require emergency venting, but local regulations should be checked.<\/p>\n<\/div>\n\n<div class=\"wanan-faq-item\">\n<h3 class=\"wanan-faq-q\">How do I convert SCFH to other flow units?<\/h3>\n<p class=\"wanan-faq-a\">1 SCFH (Standard Cubic Feet per Hour) = 0.0283 Nm3\/h (Normal cubic meters per hour) = 0.0277 m3\/h (at actual conditions, approximate). For quick reference: 1,000 SCFH is approximately 28.3 Nm3\/h or 16.7 m3\/min. This calculator displays results in SCFH; multiply by 0.0283 for Nm3\/h.<\/p>\n<\/div>\n\n<div class=\"wanan-faq-item\">\n<h3 class=\"wanan-faq-q\">What size PVRV do I need for my tank?<\/h3>\n<p class=\"wanan-faq-a\">PVRV sizing depends on the calculated venting capacity, the allowable pressure\/vacuum settings, and the valve&#8217;s flow coefficient. As a general guide: tanks up to 10,000 bbl typically use 2-inch PVRVs; 10,000-50,000 bbl use 3-4 inch; 50,000-100,000 bbl use 6-8 inch; and larger tanks may require 10-12 inch or multiple PVRVs. This calculator provides preliminary size recommendations, but a detailed flow calculation per API 2000 Appendix B should be performed.<\/p>\n<\/div>\n\n<div class=\"wanan-faq-item\">\n<h3 class=\"wanan-faq-q\">Can I use one PVRV for both normal and emergency venting?<\/h3>\n<p class=\"wanan-faq-a\">In some cases, yes. If the PVRV&#8217;s full-open capacity exceeds both the normal and emergency venting requirements, a single device may suffice. However, for larger tanks or volatile products, the emergency venting requirement is typically much higher than normal venting, requiring a separate emergency relief valve (manway cover type) in addition to the PVRV. Consult API 2000 Section 4.4.5 for combined venting guidance.<\/p>\n<\/div>\n\n<div class=\"wanan-faq-item\">\n<h3 class=\"wanan-faq-q\">How does tank insulation affect venting requirements?<\/h3>\n<p class=\"wanan-faq-a\">Insulation has two effects: (1) it reduces thermal breathing by buffering temperature changes, though API 2000 still requires full thermal breathing capacity regardless of insulation, and (2) it reduces the emergency venting requirement by lowering the heat input rate during fire exposure. The environmental factor F accounts for this: F=1.0 for bare tanks, F=0.3 for insulated tanks with conductive heat transfer analysis, and F=0 for tanks below grade or behind bunds.<\/p>\n<\/div>\n\n<\/div><!-- \/faq-list -->\n\n<hr style=\"margin:30px 0;border:none;border-top:1px solid #e0e0e0;\" \/>\n\n<p><strong>Need a complete tank safety equipment package?<\/strong> Wanan Technology manufactures <a href=\"https:\/\/wanantec.com\/product-category\/category-pressure-vacuum-valves\/\">pressure vacuum relief valves<\/a>, <a href=\"https:\/\/wanantec.com\/product-category\/category-flame-arrestor\/\">flame arrestors<\/a>, and <a href=\"https:\/\/wanantec.com\/product-category\/category-emergency-relief-valves\/\">emergency relief valves<\/a> certified to API 2000, ISO 16852, ATEX, and EAC standards. Our engineers can provide detailed vent sizing calculations and equipment selection for your specific application.<\/p>\n\n<\/div><!-- \/wanan-calculator-page -->\n\n<script>\n\/\/ API 2000 Thermal Inbreathing lookup table (7th Edition, Table 1)\n\/\/ Capacity (bbl) -> SCFH\nvar thermalInTable = [\n    [60, 30],\n    [100, 40],\n    [500, 100],\n    [1000, 180],\n    [2000, 300],\n    [4000, 500],\n    [8000, 830],\n    [10000, 1000],\n    [20000, 1700],\n    [30000, 2300],\n    [40000, 2900],\n    [50000, 3400],\n    [60000, 3900],\n    [80000, 4800],\n    [100000, 5700],\n    [120000, 6500],\n    [140000, 7300],\n    [160000, 8100],\n    [180000, 8800],\n    [200000, 9500],\n    [240000, 11000],\n    [280000, 12300],\n    [320000, 13600],\n    [360000, 14900],\n    [400000, 16200],\n    [440000, 17400],\n    [480000, 18600],\n    [520000, 19800],\n    [560000, 21000],\n    [600000, 22200]\n];\n\n\/\/ Product properties: [volatile factor, latent heat (BTU\/lb), molecular weight]\nvar productProps = {\n    crude:    { volatile: true,  latentHeat: 11000, molWeight: 80 },\n    gasoline: { volatile: true,  latentHeat: 13600, molWeight: 72 },\n    naphtha:  { volatile: true,  latentHeat: 12000, molWeight: 78 },\n    diesel:   { volatile: false, latentHeat: 9000,  molWeight: 170 },\n    jetfuel:  { volatile: false, latentHeat: 9500,  molWeight: 160 },\n    water:    { volatile: false, latentHeat: 9700,  molWeight: 18 }\n};\n\nfunction interpolateTable(table, x) {\n    if (x <= table[0][0]) return table[0][1];\n    var last = table[table.length - 1];\n    if (x >= last[0]) return last[1] * Math.pow(x \/ last[0], 0.7);\n    for (var i = 0; i < table.length - 1; i++) {\n        if (x >= table[i][0] && x <= table[i+1][0]) {\n            var t = (x - table[i][0]) \/ (table[i+1][0] - table[i][0]);\n            return table[i][1] + t * (table[i+1][1] - table[i][1]);\n        }\n    }\n    return last[1];\n}\n\nfunction calculateVenting() {\n    var capacity = parseFloat(document.getElementById('tankCapacity').value);\n    var diameter = parseFloat(document.getElementById('tankDiameter').value);\n    var liqHeight = parseFloat(document.getElementById('tankHeight').value);\n    var product = document.getElementById('productType').value;\n    var pumpIn = parseFloat(document.getElementById('pumpInRate').value) || 0;\n    var pumpOut = parseFloat(document.getElementById('pumpOutRate').value) || 0;\n    var F = parseFloat(document.getElementById('insulation').value);\n\n    if (!capacity || !diameter || !liqHeight) {\n        alert('Please fill in all required fields.');\n        return;\n    }\n\n    var props = productProps[product] || productProps.crude;\n\n    \/\/ --- Normal Inbreathing ---\n    var thermalIn = interpolateTable(thermalInTable, capacity);\n    var pumpOutIn = pumpOut * 5.6; \/\/ SCFH per GPM\n    var totalIn = thermalIn + pumpOutIn;\n\n    \/\/ --- Normal Outbreathing ---\n    var thermalOut = props.volatile ? thermalIn * 0.5 : thermalIn * 0.25;\n    var pumpInOut = pumpIn * (props.volatile ? 2.0 : 1.0); \/\/ SCFH per GPM\n    var totalOut = thermalOut + pumpInOut;\n\n    \/\/ --- Emergency Venting (Fire Exposure) ---\n    \/\/ Wetted surface area: cylinder area up to 30 ft height\n    var effectiveHeight = Math.min(liqHeight, 30); \/\/ API 2000: max 30 ft above grade\n    var wettedArea = Math.PI * diameter * effectiveHeight; \/\/ ft^2\n\n    \/\/ Emergency venting formula (simplified API 2000 4.4)\n    \/\/ V = 1107 * F * A^0.82 \/ (L * sqrt(M))\n    var emergencyVent = 0;\n    if (F > 0 && wettedArea > 0) {\n        emergencyVent = 1107 * F * Math.pow(wettedArea, 0.82) \/ (props.latentHeat * Math.sqrt(props.molWeight));\n        \/\/ Convert to SCFH (formula gives CFH at boiling conditions, approximate conversion)\n        emergencyVent = emergencyVent * 1.0; \/\/ Already in approximate SCFH\n    }\n\n    \/\/ --- Equipment Recommendations ---\n    var maxFlow = Math.max(totalIn, totalOut);\n    var pvrvSize = '2 inch (DN50)';\n    if (maxFlow > 5000) pvrvSize = '3 inch (DN80)';\n    if (maxFlow > 15000) pvrvSize = '4 inch (DN100)';\n    if (maxFlow > 35000) pvrvSize = '6 inch (DN150)';\n    if (maxFlow > 80000) pvrvSize = '8 inch (DN200)';\n    if (maxFlow > 150000) pvrvSize = '10 inch (DN250)';\n    if (maxFlow > 250000) pvrvSize = '12 inch (DN300) or dual PVRVs';\n\n    var faSize = pvrvSize.replace(' or dual PVRVs', '');\n\n    var ervSize = 'Not required (non-flammable)';\n    if (props.volatile || product === 'water') {\n        if (emergencyVent > 0) {\n            if (emergencyVent < 50000) ervSize = '12 inch (DN300) manway';\n            else if (emergencyVent < 150000) ervSize = '16 inch (DN400) manway';\n            else if (emergencyVent < 300000) ervSize = '20 inch (DN500) manway';\n            else ervSize = '24 inch (DN600) manway or multiple ERVs';\n        }\n    }\n\n    \/\/ --- Display Results ---\n    document.getElementById('thermalIn').textContent = Math.round(thermalIn).toLocaleString() + ' SCFH';\n    document.getElementById('pumpOutIn').textContent = Math.round(pumpOutIn).toLocaleString() + ' SCFH';\n    document.getElementById('totalIn').textContent = Math.round(totalIn).toLocaleString() + ' SCFH';\n\n    document.getElementById('thermalOut').textContent = Math.round(thermalOut).toLocaleString() + ' SCFH';\n    document.getElementById('pumpInOut').textContent = Math.round(pumpInOut).toLocaleString() + ' SCFH';\n    document.getElementById('totalOut').textContent = Math.round(totalOut).toLocaleString() + ' SCFH';\n\n    document.getElementById('wettedArea').textContent = Math.round(wettedArea).toLocaleString() + ' ftu00b2';\n    document.getElementById('envFactor').textContent = 'F = ' + F;\n    if (emergencyVent > 0) {\n        document.getElementById('emergencyVent').textContent = Math.round(emergencyVent).toLocaleString() + ' SCFH';\n    } else {\n        document.getElementById('emergencyVent').textContent = 'N\/A (underground\/bunded)';\n    }\n\n    document.getElementById('pvrvSize').textContent = pvrvSize;\n    document.getElementById('faSize').textContent = faSize + ' end-of-line flame arrestor';\n    document.getElementById('ervSize').textContent = ervSize;\n\n    document.getElementById('calcResults').style.display = 'block';\n    document.getElementById('calcResults').scrollIntoView({ behavior: 'smooth' });\n}\n\nfunction resetCalculator() {\n    document.getElementById('tankCapacity').value = 20000;\n    document.getElementById('tankDiameter').value = 100;\n    document.getElementById('tankHeight').value = 40;\n    document.getElementById('productType').value = 'crude';\n    document.getElementById('pumpInRate').value = 500;\n    document.getElementById('pumpOutRate').value = 500;\n    document.getElementById('insulation').value = '1.0';\n    document.getElementById('calcResults').style.display = 'none';\n}\n<\/script>","protected":false},"excerpt":{"rendered":"<p>API 2000 Storage Tank Vent Sizing Calculator Use this calculator to estimate the required venting capacity for atmospheric storage tanks based on API 2000 7th Edition. Enter your tank parameters below to determine normal inbreathing, normal outbreathing, and emergency venting requirements. Disclaimer: This calculator provides preliminary estimates for reference only. Actual vent sizing must be [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"class_list":["post-4843","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/wanantec.com\/zh\/wp-json\/wp\/v2\/pages\/4843","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wanantec.com\/zh\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/wanantec.com\/zh\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/wanantec.com\/zh\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wanantec.com\/zh\/wp-json\/wp\/v2\/comments?post=4843"}],"version-history":[{"count":0,"href":"https:\/\/wanantec.com\/zh\/wp-json\/wp\/v2\/pages\/4843\/revisions"}],"wp:attachment":[{"href":"https:\/\/wanantec.com\/zh\/wp-json\/wp\/v2\/media?parent=4843"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}