{"id":1755,"date":"2026-04-27T05:41:39","date_gmt":"2026-04-27T12:41:39","guid":{"rendered":"https:\/\/www.songhaiflanges.com\/?p=1755"},"modified":"2026-04-27T06:00:14","modified_gmt":"2026-04-27T13:00:14","slug":"flange-sizes-complete-selection-guide-for-industrial-piping-applications","status":"publish","type":"post","link":"https:\/\/www.songhaiflanges.com\/es\/flange-sizes-complete-selection-guide-for-industrial-piping-applications\/","title":{"rendered":"Flange Sizes: Complete Selection Guide for Industrial Piping Applications"},"content":{"rendered":"<h2>Introduction: Understanding Flange Sizes and Specifications<\/h2>\n<p>Selecting the <strong>correct flange size<\/strong> is critical for safe, reliable piping system operation. Flange sizing involves matching nominal pipe size, pressure class, material, and dimensional specifications to your application requirements. This comprehensive guide covers everything engineers and procurement professionals need to know about flange sizes and selection.<\/p>\n<h2>Flange Sizing Fundamentals<\/h2>\n<h3>What Does Flange Size Mean?<\/h3>\n<p>Flange size is defined by several key parameters:<\/p>\n<ol>\n<li><strong>Nominal Pipe Size (NPS):<\/strong> Standard pipe diameter designation (1\/2&#8243; to 60&#8243;)<\/li>\n<li><strong>Diameter Nominal (DN):<\/strong> Metric equivalent (DN15 to DN1500)<\/li>\n<li><strong>Pressure Class:<\/strong> Pressure rating (150, 300, 600, 900, 1500, 2500)<\/li>\n<li><strong>Bore Diameter:<\/strong> Inside diameter matching pipe OD<\/li>\n<li><strong>Outside Diameter (OD):<\/strong> Overall flange diameter<\/li>\n<li><strong>Bolt Circle Diameter:<\/strong> Circle through bolt hole centers<\/li>\n<li><strong>Number of Bolt Holes:<\/strong> Varies by size and class<\/li>\n<li><strong>Bolt Hole Size:<\/strong> Diameter for bolts\/studs<\/li>\n<\/ol>\n<h2>Standard Flange Size Charts<\/h2>\n<h3>ASME B16.5 Flange Dimensions (Class 150)<\/h3>\n<table>\n<tr>\n<th>NPS<\/th>\n<th>DN<\/th>\n<th>OD (mm)<\/th>\n<th>Bolt Circle (mm)<\/th>\n<th>Bolt Holes<\/th>\n<th>Bolt Size<\/th>\n<\/tr>\n<tr>\n<td>1\/2&#8243;<\/td>\n<td>15<\/td>\n<td>89<\/td>\n<td>60<\/td>\n<td>4<\/td>\n<td>M12<\/td>\n<\/tr>\n<tr>\n<td>1&#8243;<\/td>\n<td>25<\/td>\n<td>110<\/td>\n<td>79<\/td>\n<td>4<\/td>\n<td>M14<\/td>\n<\/tr>\n<tr>\n<td>2&#8243;<\/td>\n<td>50<\/td>\n<td>152<\/td>\n<td>121<\/td>\n<td>4<\/td>\n<td>M16<\/td>\n<\/tr>\n<tr>\n<td>3&#8243;<\/td>\n<td>80<\/td>\n<td>191<\/td>\n<td>152<\/td>\n<td>4<\/td>\n<td>M16<\/td>\n<\/tr>\n<tr>\n<td>4&#8243;<\/td>\n<td>100<\/td>\n<td>229<\/td>\n<td>191<\/td>\n<td>8<\/td>\n<td>M16<\/td>\n<\/tr>\n<tr>\n<td>6&#8243;<\/td>\n<td>150<\/td>\n<td>279<\/td>\n<td>241<\/td>\n<td>8<\/td>\n<td>M20<\/td>\n<\/tr>\n<tr>\n<td>8&#8243;<\/td>\n<td>200<\/td>\n<td>343<\/td>\n<td>298<\/td>\n<td>8<\/td>\n<td>M22<\/td>\n<\/tr>\n<tr>\n<td>10&#8243;<\/td>\n<td>250<\/td>\n<td>406<\/td>\n<td>362<\/td>\n<td>12<\/td>\n<td>M22<\/td>\n<\/tr>\n<tr>\n<td>12&#8243;<\/td>\n<td>300<\/td>\n<td>483<\/td>\n<td>432<\/td>\n<td>12<\/td>\n<td>M24<\/td>\n<\/tr>\n<tr>\n<td>16&#8243;<\/td>\n<td>400<\/td>\n<td>610<\/td>\n<td>552<\/td>\n<td>16<\/td>\n<td>M27<\/td>\n<\/tr>\n<tr>\n<td>20&#8243;<\/td>\n<td>500<\/td>\n<td>749<\/td>\n<td>686<\/td>\n<td>20<\/td>\n<td>M30<\/td>\n<\/tr>\n<tr>\n<td>24&#8243;<\/td>\n<td>600<\/td>\n<td>914<\/td>\n<td>838<\/td>\n<td>20<\/td>\n<td>M33<\/td>\n<\/tr>\n<\/table>\n<h3>ASME B16.5 Flange Dimensions (Class 300)<\/h3>\n<table>\n<tr>\n<th>NPS<\/th>\n<th>DN<\/th>\n<th>OD (mm)<\/th>\n<th>Bolt Circle (mm)<\/th>\n<th>Bolt Holes<\/th>\n<th>Bolt Size<\/th>\n<\/tr>\n<tr>\n<td>1\/2&#8243;<\/td>\n<td>15<\/td>\n<td>95<\/td>\n<td>67<\/td>\n<td>4<\/td>\n<td>M14<\/td>\n<\/tr>\n<tr>\n<td>1&#8243;<\/td>\n<td>25<\/td>\n<td>124<\/td>\n<td>89<\/td>\n<td>4<\/td>\n<td>M16<\/td>\n<\/tr>\n<tr>\n<td>2&#8243;<\/td>\n<td>50<\/td>\n<td>165<\/td>\n<td>127<\/td>\n<td>8<\/td>\n<td>M16<\/td>\n<\/tr>\n<tr>\n<td>3&#8243;<\/td>\n<td>80<\/td>\n<td>210<\/td>\n<td>168<\/td>\n<td>8<\/td>\n<td>M20<\/td>\n<\/tr>\n<tr>\n<td>4&#8243;<\/td>\n<td>100<\/td>\n<td>254<\/td>\n<td>200<\/td>\n<td>8<\/td>\n<td>M22<\/td>\n<\/tr>\n<tr>\n<td>6&#8243;<\/td>\n<td>150<\/td>\n<td>318<\/td>\n<td>270<\/td>\n<td>12<\/td>\n<td>M22<\/td>\n<\/tr>\n<tr>\n<td>8&#8243;<\/td>\n<td>200<\/td>\n<td>381<\/td>\n<td>330<\/td>\n<td>12<\/td>\n<td>M24<\/td>\n<\/tr>\n<tr>\n<td>10&#8243;<\/td>\n<td>250<\/td>\n<td>445<\/td>\n<td>387<\/td>\n<td>16<\/td>\n<td>M27<\/td>\n<\/tr>\n<tr>\n<td>12&#8243;<\/td>\n<td>300<\/td>\n<td>521<\/td>\n<td>470<\/td>\n<td>16<\/td>\n<td>M30<\/td>\n<\/tr>\n<\/table>\n<h2>Flange Sizing: Step-by-Step Selection Process<\/h2>\n<h3>Step 1: Determine Nominal Pipe Size<\/h3>\n<p>Identify the pipe size based on:<\/p>\n<ul>\n<li>Flow rate requirements<\/li>\n<li>Fluid velocity limits<\/li>\n<li>Pressure drop considerations<\/li>\n<li>Existing system compatibility<\/li>\n<\/ul>\n<h3>Step 2: Calculate Design Pressure<\/h3>\n<p>Consider:<\/p>\n<ul>\n<li>Maximum operating pressure<\/li>\n<li>Pressure surges and water hammer<\/li>\n<li>Test pressure requirements (1.5x design pressure)<\/li>\n<li>Safety margin (typically 10-20%)<\/li>\n<\/ul>\n<h3>Step 3: Select Pressure Class<\/h3>\n<table>\n<tr>\n<th>Class<\/th>\n<th>Max Pressure (bar) @ 100\u00b0F<\/th>\n<th>Typical Applications<\/th>\n<\/tr>\n<tr>\n<td>150<\/td>\n<td>19.6<\/td>\n<td>Water, air, low-pressure process<\/td>\n<\/tr>\n<tr>\n<td>300<\/td>\n<td>51.7<\/td>\n<td>General process piping<\/td>\n<\/tr>\n<tr>\n<td>600<\/td>\n<td>103.4<\/td>\n<td>High-pressure process<\/td>\n<\/tr>\n<tr>\n<td>900<\/td>\n<td>155.1<\/td>\n<td>High-pressure steam<\/td>\n<\/tr>\n<tr>\n<td>1500<\/td>\n<td>258.6<\/td>\n<td>Critical high-pressure<\/td>\n<\/tr>\n<tr>\n<td>2500<\/td>\n<td>431.0<\/td>\n<td>Ultra-high pressure<\/td>\n<\/tr>\n<\/table>\n<h3>Step 4: Choose Material<\/h3>\n<p>Material selection based on:<\/p>\n<ul>\n<li><strong>Carbon Steel (A105):<\/strong> General service, -20\u00b0F to 800\u00b0F<\/li>\n<li><strong>Low-Temp Carbon (A350 LF2):<\/strong> Cryogenic to -50\u00b0F<\/li>\n<li><strong>Stainless 304\/316:<\/strong> Corrosive service, high temperature<\/li>\n<li><strong>Duplex 2205:<\/strong> Chloride environments, high strength<\/li>\n<li><strong>Alloy F11\/F22:<\/strong> High-temperature service<\/li>\n<\/ul>\n<h3>Step 5: Select Flange Type<\/h3>\n<ul>\n<li><strong>Weld Neck:<\/strong> Critical, high-pressure, high-temperature<\/li>\n<li><strong>Slip On:<\/strong> General service, cost-sensitive<\/li>\n<li><strong>Blind:<\/strong> End closures, isolation points<\/li>\n<li><strong>Socket Weld:<\/strong> Small bore, high-pressure<\/li>\n<li><strong>Threaded:<\/strong> No-weld applications<\/li>\n<li><strong>Lap Joint:<\/strong> Frequent disassembly<\/li>\n<\/ul>\n<h2>Flange Size Tolerances<\/h2>\n<h3>ASME B16.5 Dimensional Tolerances:<\/h3>\n<ul>\n<li><strong>Outside Diameter:<\/strong> \u00b11.5mm for NPS \u2264 18&#8243;, \u00b13mm for NPS \u2265 20&#8243;<\/li>\n<li><strong>Bolt Circle:<\/strong> \u00b10.8mm for NPS \u2264 18&#8243;, \u00b11.5mm for NPS \u2265 20&#8243;<\/li>\n<li><strong>Flange Thickness:<\/strong> +2.5mm \/ -1.5mm<\/li>\n<li><strong>Bolt Hole Diameter:<\/strong> +1.5mm \/ -0mm<\/li>\n<li><strong>Bolt Hole Location:<\/strong> \u00b10.8mm<\/li>\n<li><strong>Flange Face Perpendicularity:<\/strong> 0.25mm per 100mm OD<\/li>\n<\/ul>\n<h2>Special Flange Size Considerations<\/h2>\n<h3>Large Diameter Flanges (NPS 26&#8243; and Above)<\/h3>\n<p>For flanges exceeding NPS 24&#8243;, ASME B16.47 applies:<\/p>\n<ul>\n<li><strong>Series A:<\/strong> Heavier, more bolt holes (MSS SP-44 origin)<\/li>\n<li><strong>Series B:<\/strong> Lighter, fewer bolt holes (API 605 origin)<\/li>\n<li><strong>Size Range:<\/strong> NPS 26&#8243; to NPS 60&#8243;<\/li>\n<li><strong>Pressure Classes:<\/strong> 75, 150, 300, 400, 600, 900<\/li>\n<\/ul>\n<h3>Reducing Flanges (Offset Flange Applications)<\/h3>\n<p>When connecting different pipe sizes:<\/p>\n<ul>\n<li>Use reducing flanges or weld neck with reducer<\/li>\n<li>Ensure proper bore transition<\/li>\n<li>Consider flow turbulence effects<\/li>\n<li>Verify pressure rating based on smaller size<\/li>\n<\/ul>\n<h2>Flanged Bearings and Special Applications<\/h2>\n<h3>Flanged Bearings:<\/h3>\n<p>Flanged bearings use a mounting flange for secure attachment. Key considerations:<\/p>\n<ul>\n<li>Bolt pattern compatibility<\/li>\n<li>Load distribution through flange<\/li>\n<li>Alignment requirements<\/li>\n<li>Lubrication access<\/li>\n<\/ul>\n<h3>Flanged Girder Applications:<\/h3>\n<p>Structural flanged girders require:<\/p>\n<ul>\n<li>Heavy-duty bolting<\/li>\n<li>Precision machining of flange faces<\/li>\n<li>Load calculations for flange thickness<\/li>\n<li>Welding procedures for girder-to-flange connection<\/li>\n<\/ul>\n<h2>Common Flange Sizing Mistakes<\/h2>\n<h3>1. Incorrect Pressure Class Selection<\/h3>\n<p><strong>Problem:<\/strong> Selecting Class 150 for 300 psi service without temperature derating.<\/p>\n<p><strong>Solution:<\/strong> Always check pressure-temperature ratings for operating conditions.<\/p>\n<h3>2. Mismatched Bolt Patterns<\/h3>\n<p><strong>Problem:<\/strong> Ordering flanges with incompatible bolt circles.<\/p>\n<p><strong>Solution:<\/strong> Verify all dimensions match existing or mating flanges.<\/p>\n<h3>3. Wrong Bore Size<\/h3>\n<p><strong>Problem:<\/strong> Flange bore too small or too large for pipe OD.<\/p>\n<p><strong>Solution:<\/strong> Specify pipe schedule when ordering flanges.<\/p>\n<h3>4. Ignoring Temperature Effects<\/h3>\n<p><strong>Problem:<\/strong> Pressure rating decreases at elevated temperatures.<\/p>\n<p><strong>Solution:<\/strong> Use ASME B16.5 pressure-temperature tables.<\/p>\n<h2>Flange Size Verification Checklist<\/h2>\n<p>Before ordering or installing flanges, verify:<\/p>\n<ul>\n<li>\u2713 Nominal pipe size (NPS\/DN)<\/li>\n<li>\u2713 Pressure class rating<\/li>\n<li>\u2713 Flange type (WN, SO, BL, SW, etc.)<\/li>\n<li>\u2713 Face type (RF, FF, RTJ)<\/li>\n<li>\u2713 Material specification<\/li>\n<li>\u2713 Bore diameter matches pipe OD<\/li>\n<li>\u2713 Bolt circle and hole pattern<\/li>\n<li>\u2713 Flange thickness<\/li>\n<li>\u2713 Raised face height (if applicable)<\/li>\n<li>\u2713 Applicable standard (ASME B16.5, B16.47, EN 1092-1)<\/li>\n<\/ul>\n<h2>Quality Documentation Requirements<\/h2>\n<p>Ensure suppliers provide:<\/p>\n<ul>\n<li>\u2713 Material Test Report (MTR) per ASTM<\/li>\n<li>\u2713 Dimensional inspection certificate<\/li>\n<li>\u2713 Chemical analysis report<\/li>\n<li>\u2713 Mechanical property test results<\/li>\n<li>\u2713 Heat treatment records (if applicable)<\/li>\n<li>\u2713 Third-party inspection (SGS, BV, TUV) when required<\/li>\n<\/ul>\n<h2>Conclusion<\/h2>\n<p>Proper flange sizing is essential for safe, reliable piping system operation. Understanding flange sizes, pressure classes, materials, and dimensional specifications ensures correct selection for your application. Always consult ASME B16.5, B16.47, or applicable standards, and work with reputable manufacturers who can provide full certification and technical support.<\/p>\n<p>For complex applications or when in doubt, engage experienced piping engineers to review flange selections and verify compatibility with system requirements.<\/p>\n<hr>\n<p><em>Keywords: flange sizes, flange sizing, correct flange size, flanged bearings, flanged girder, flanges meaning, flanging, offset flange, PVC closet flange, industrial flange dimensions, ASME B16.5, pressure class flange<\/em><\/p>\n<p><strong>WhatsApp:<\/strong>\u00a0+86-18658777855<br \/>\n<strong>Email:<\/strong>\u00a01007788887@qq.com<br \/>\n<a href=\"https:\/\/www.720yun.com\/vr\/a6ajt7ynrw0\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1480\" src=\"http:\/\/www.songhaiflanges.com\/wp-content\/uploads\/2026\/04\/4-1.webp\" alt=\"\" width=\"1290\" height=\"2317\" srcset=\"https:\/\/www.songhaiflanges.com\/wp-content\/uploads\/2026\/04\/4-1.webp 1290w, https:\/\/www.songhaiflanges.com\/wp-content\/uploads\/2026\/04\/4-1-167x300.webp 167w, https:\/\/www.songhaiflanges.com\/wp-content\/uploads\/2026\/04\/4-1-570x1024.webp 570w, https:\/\/www.songhaiflanges.com\/wp-content\/uploads\/2026\/04\/4-1-768x1379.webp 768w, https:\/\/www.songhaiflanges.com\/wp-content\/uploads\/2026\/04\/4-1-855x1536.webp 855w, https:\/\/www.songhaiflanges.com\/wp-content\/uploads\/2026\/04\/4-1-1140x2048.webp 1140w, https:\/\/www.songhaiflanges.com\/wp-content\/uploads\/2026\/04\/4-1-7x12.webp 7w\" sizes=\"auto, (max-width: 1290px) 100vw, 1290px\" \/><\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Complete flange sizes selection guide covering dimensions, pressure classes, materials, tolerances, and step-by-step sizing process for industrial piping applications.<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"default","_kad_post_title":"default","_kad_post_layout":"default","_kad_post_sidebar_id":"","_kad_post_content_style":"default","_kad_post_vertical_padding":"default","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"footnotes":""},"categories":[1],"tags":[122,358,155,353,357,354,172,158],"class_list":["post-1755","post","type-post","status-publish","format-standard","hentry","category-3-news","tag-asme-b16-5","tag-engineering-guide","tag-flange-dimensions","tag-flange-sizes","tag-flange-sizing","tag-industrial-flange","tag-piping-design","tag-pressure-class"],"_links":{"self":[{"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/posts\/1755","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/comments?post=1755"}],"version-history":[{"count":2,"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/posts\/1755\/revisions"}],"predecessor-version":[{"id":1770,"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/posts\/1755\/revisions\/1770"}],"wp:attachment":[{"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/media?parent=1755"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/categories?post=1755"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.songhaiflanges.com\/es\/wp-json\/wp\/v2\/tags?post=1755"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}