{"id":230,"date":"2018-01-11T09:50:55","date_gmt":"2018-01-11T09:50:55","guid":{"rendered":"https:\/\/www.orslabs.fr\/?page_id=230"},"modified":"2025-06-22T15:16:29","modified_gmt":"2025-06-22T13:16:29","slug":"howl-mann-equation","status":"publish","type":"page","link":"https:\/\/www.orslabs.fr\/en\/tools\/howl-mann-equation\/","title":{"rendered":"Howl-Mann Equation"},"content":{"rendered":"\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-l8rta-33b83f4cff5753a42319c03b8605dba2\">\n.flex_column.av-l8rta-33b83f4cff5753a42319c03b8605dba2{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-l8rta-33b83f4cff5753a42319c03b8605dba2 av_one_full  avia-builder-el-0  el_before_av_one_full  avia-builder-el-first  first flex_column_div av-zero-column-padding  '     ><style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-kkmy1j31-3acff0cdf7acbcbc48d12a116a84b945\">\n#top .av-special-heading.av-kkmy1j31-3acff0cdf7acbcbc48d12a116a84b945{\npadding-bottom:10px;\n}\nbody .av-special-heading.av-kkmy1j31-3acff0cdf7acbcbc48d12a116a84b945 .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-kkmy1j31-3acff0cdf7acbcbc48d12a116a84b945 .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-kkmy1j31-3acff0cdf7acbcbc48d12a116a84b945 av-special-heading-h1 blockquote modern-quote modern-centered  avia-builder-el-1  avia-builder-el-no-sibling  av-linked-heading'><h1 class='av-special-heading-tag'  itemprop=\"headline\"  >Howl-Mann Equation<\/h1><div class=\"special-heading-border\"><div class=\"special-heading-inner-border\"><\/div><\/div><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-9hafy-a2cc44c9153b8dcf71486007e509bf21\">\n.flex_column.av-9hafy-a2cc44c9153b8dcf71486007e509bf21{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-9hafy-a2cc44c9153b8dcf71486007e509bf21 av_one_full  avia-builder-el-2  el_after_av_one_full  avia-builder-el-last  first flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-juns62qr-f7dba33603ea182e67c24a5091b3d727 '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\" ><div class='avia_textblock'  itemprop=\"text\" ><p>Back in 1965, D A Howl and C A Mann published &#8220;The back-pressurizing technique of leak-testing&#8221;. <em>The technique of leak-testing sealed objects is examined in which the object is first pressurized in a tracer gas and afterwards tested for re-emission of the gas.<\/em> The technical article establishes an equation which gives the measured leak rate (R1), for a leak showing purely molecular flow, as a function of the leak size (L), internal volume (V), and pressurization parameters.<\/p>\n<p>The &#8220;Howl-Mann&#8221; equation is now present in Mil-Std-883 TM-1014 and Mil-Std-750 Test Method 1071 documents, and is mainly used to set test parameters and Pass\/Fail criteria for <a href=\"\/en\/hermeticity\/hshld-high-sensitivity-helium-leak-detection\/\">Helium Fine Leak Testing<\/a>.<\/p>\n<p>The interactive form below helps you compute the R1 Pass\/Fail criteria based on your leak test parameters. The form also does the reverse computation (i.e. it computes the Total Leak Rate (L) from the Measured Leak rate (R1)).<\/p>\n<iframe loading=\"lazy\" id=\"Howl-Mann Equation\" name=\"Howl-Mann Equation\" src=\"\/ors-tools\/howl-mann.html\" width=\"100%\" height=\"2000px\" frameborder=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/section><\/div><\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":13,"featured_media":0,"parent":218,"menu_order":3,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":"","_links_to":"","_links_to_target":""},"class_list":["post-230","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v24.9 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Howl-Mann Equation | Oneida Research Services |<\/title>\n<meta name=\"description\" content=\"The Howl-Mann Equation is used to calculate leak testing pressurization requirements needed for 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