{"id":10421,"date":"2026-07-20T14:36:45","date_gmt":"2026-07-20T12:36:45","guid":{"rendered":"https:\/\/lasttechnology.it\/general\/test-bowie-dick-autoclave\/"},"modified":"2026-07-20T14:44:21","modified_gmt":"2026-07-20T12:44:21","slug":"bowie-dick-test-autoclave","status":"publish","type":"post","link":"https:\/\/lasttechnology.it\/en\/news-en\/bowie-dick-test-autoclave\/","title":{"rendered":"Bowie-Dick test: what it is, how it works, and why it matters"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><strong>The Bowie-Dick test is a routine check that confirms a fractionated vacuum autoclave removes air completely from the chamber and lets saturated steam penetrate evenly through porous loads.<\/strong> It is a functional check of the equipment, not a proof of sterility for an individual load.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In steam sterilization, trapped air is the most common reason a cycle fails. Air is a thermal insulator: where it lingers, steam cannot reach the surface properly and microbial lethality can be reduced. The Bowie-Dick test is the long-established way to catch this problem before it compromises a production or laboratory cycle. In pharmaceutical, biotech, and laboratory settings it is part of daily quality control for fractionated vacuum autoclaves.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>In brief: what the Bowie-Dick test checks<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The Bowie-Dick test confirms whether a fractionated vacuum autoclave evacuates air properly and allows saturated steam to penetrate porous loads uniformly. It is normally run on an empty chamber, with a dedicated test pack, before the first cycle of the day. A failed result points to residual air pockets, leaks in the vacuum circuit, or poor steam penetration.<strong><\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What is the Bowie-Dick test<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The Bowie-Dick test is a diagnostic check of the air-removal performance of a fractionated vacuum autoclave and of the ability of saturated steam to penetrate a reference porous load evenly. It applies only to sterilizers that use dynamic air removal (fractionated vacuum), not to gravity-displacement units.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Run regularly, the test detects:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>residual air left in the sterilization chamber;<\/li>\n\n\n\n<li>leaks in the vacuum circuit;<\/li>\n\n\n\n<li>insufficient or uneven steam penetration;<\/li>\n\n\n\n<li>vacuum-pump or air-extraction faults.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What the Bowie-Dick test does not verify<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The Bowie-Dick test does not prove the sterility of a load, does not directly measure the F0 value, and does not replace cycle qualification or validation. Its purpose is narrower: to confirm that the autoclave can remove air and let steam penetrate porous materials. For that reason it should be treated as a functional check of the equipment, not as a sterility assurance test for the product. Sterility is demonstrated through validation (IQ\/OQ\/PQ) and through the prescribed chemical and biological controls.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Origin: who were Bowie and Dick<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The test is named after J.H. Bowie and J. Dick, two British researchers who, in the early 1960s, developed a way to check that porous loads such as textiles and gowns were being sterilized correctly in UK hospitals. Formalized in 1963, it quickly became a daily control for healthcare sterilizers and is today an internationally recognized standard, embedded in the main technical norms for moist-heat sterilization.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>How the Bowie-Dick test works<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The test relies on a test pack, or an equivalent device, that holds a chemical indicator sensitive to the combination of time, temperature, and saturated steam. During a dedicated cycle, steam must reach the center of the pack uniformly. When air removal is correct, the indicator shows an even color change across its whole surface. An uneven change signals trapped air or poor steam distribution.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Air, or non-condensable gases, breaks the contact between saturated steam and the surface being treated. Unlike steam, which condenses and releases latent heat, air acts as an insulating barrier and can create cold spots inside the load. This is why incomplete air removal can defeat a cycle that looks correct on paper in terms of temperature and time:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a><\/a><strong>The standard test cycle<\/strong><\/h3>\n\n\n\n<h3 class=\"wp-block-heading\">The reference cycle for the Bowie &amp; Dick test involves exposure to a sterilisation temperature for the duration specified by the manufacturer of the test pack.<\/h3>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Bowie-Dick test pack vs electronic Bowie-Dick test<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Traditional Bowie-Dick testing uses a physical test pack with a chemical indicator sheet that changes color when air removal and steam penetration are adequate. An electronic Bowie-Dick device reproduces the same air-removal challenge and returns a digital, instrument-read record of the test. In regulated pharmaceutical environments, electronic systems can simplify archiving and trend analysis, provided the data are managed under validated procedures and compliant electronic-record controls.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a><\/a><strong>Step by step<\/strong><\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Place the test pack at the center of the lowest shelf, in an otherwise empty chamber.<\/li>\n\n\n\n<li>Start the dedicated Bowie-Dick program.<\/li>\n\n\n\n<li>Run the cycle at the specified conditions (exposure to a sterilisation temperature and for a duration specified by the manufacturer of the test pack).<\/li>\n\n\n\n<li>Read and interpret the indicator, then record and archive the result.<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>When to run the Bowie-Dick test<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Frequency is set by site procedures (SOPs) and applicable standards. Established practice is to run it:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>daily, before the first sterilization cycle;<\/li>\n\n\n\n<li>after any maintenance or repair;<\/li>\n\n\n\n<li>after replacing critical components such as door gaskets;<\/li>\n\n\n\n<li>after a prolonged period of inactivity;<\/li>\n\n\n\n<li>during qualification and validation activities (in particular PQ).<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Who should run the Bowie-Dick test<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The Bowie-Dick test is relevant for any facility that uses dynamic air-removal steam sterilizers, including pharmaceutical production sites, biotechnology facilities, QC and research laboratories, hospital sterile services departments, and other regulated environments where porous or wrapped materials are processed. In each case the test should be run according to the site\u2019s SOPs, the applicable standard, and the validated configuration of the sterilizer.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>How to read the result<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Reading the indicator gives two possible outcomes:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a><\/a><strong>Pass<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The color change is uniform across the whole indicator. This means air was removed correctly, steam penetrated the pack evenly, and the chamber is fit for production or laboratory cycles.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a><\/a><strong>Fail<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The color change is uneven, with unchanged or lighter areas, typically at the center of the pack, where air tends to collect. This can indicate residual air pockets, leaks in the vacuum circuit, pump inefficiency, or uneven steam distribution. In this case the autoclave should not be used until the cause is identified and resolved, and a leak test has been repeated if needed.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Common causes of a failed Bowie-Dick test<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A failed result can come from several technical causes, including:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>loss of seal at the door or gaskets;<\/li>\n\n\n\n<li>an inefficient vacuum pump;<\/li>\n\n\n\n<li>residual air in the chamber;<\/li>\n\n\n\n<li>inadequate steam quality;<\/li>\n\n\n\n<li>the presence of non-condensable gases;<\/li>\n\n\n\n<li>incorrect placement of the test pack;<\/li>\n\n\n\n<li>use of an unsuitable test pack or one not handled per procedure.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Bowie-Dick test vs Helix test vs leak test<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The Bowie-Dick test belongs to a family of functional checks that are often confused. Each verifies a different aspect of the process:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Test<\/strong><strong><\/strong> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>What it verifies<\/strong><strong><\/strong> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><td><strong>Reference load<\/strong><strong><\/strong> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><\/tr><tr><td>Bowie-Dick \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/td><td>Air removal and steam penetration in porous materials &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><td>Porous load (e.g. textiles) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><\/tr><tr><td>Helix test \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/td><td>Steam penetration in hollow&nbsp; items and narrow lumens &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><td>Hollow load (tubes, lumens) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><\/tr><tr><td>Leak \/ vacuum test &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><td>Tightness of the vacuum circuit and absence of air ingress &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><td>Empty chamber &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><br><strong>Standards and regulatory references<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In a regulated industry the normative context is decisive. The main references for the Bowie-Dick test and the loads it covers are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>EN 285, requirements for large steam sterilizers (industrial and hospital volumes);<\/li>\n\n\n\n<li>EN 13060, requirements for small steam sterilizers;<\/li>\n\n\n\n<li>ISO 11140-3 and ISO 11140-4, specifications for the chemical indicators used in steam-penetration testing (sheet indicator and electronic simulator, respectively);<\/li>\n\n\n\n<li>ISO 17665, validation and routine control of moist-heat sterilization for medical devices (which superseded the former EN 554);<\/li>\n\n\n\n<li>AAMI ST79, the reference practice for steam sterilization in many healthcare \u00a0\u00a0\u00a0\u00a0 facilities.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">In pharmaceutical manufacturing, the test sits within the cGMP quality system and the principles of data integrity (ALCOA+), with results retained as verifiable records in line with FDA 21 CFR Part 11 and EU GMP Annex 11, and with the broader expectations of EU GMP Annex 1 for sterile products.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>The Bowie-Dick test in a cGMP environment<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In pharmaceutical production and research laboratories, the Bowie-Dick test is not an isolated check but one link in the quality-assurance chain: it confirms that every porous-load cycle starts from verified conditions, supports qualification activities (PQ), and produces traceable data ready for audits.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In a regulated environment the result must be handled as a GMP record. The documentation should capture the date and time of the test, the autoclave identifier, the operator, the cycle used, the lot or code of the test pack, the outcome, any anomalies, and the corrective actions taken in case of a failure. In electronic systems, these data must be protected against unauthorized access, untracked changes, and unjustified deletion.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Steam penetration also has to be considered together with the quality of the steam itself. In cGMP lines, the Bowie-Dick test therefore fits into a wider system that includes the autoclave, clean-steam generation, control of critical parameters, and full cycle traceability.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Fractionated vacuum autoclaves with built-in test programs<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">LAST Technology\u2019s fractional vacuum autoclaves feature automated programmes designed for Bowie &amp; Dick testing, with the results recorded and archived. In this way, routine quality checks become part of daily operation and support traceability in regulated environments.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This approach is available in the NEBULA steam autoclave series and RSA saturated-steam autoclave series. Where required, these systems can be integrated with CSG clean-steam generators to support the overall steam sterilization process.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Conclusion<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The Bowie-Dick test is a quick but decisive check: it confirms that a fractionated vacuum autoclave removes air and distributes steam evenly across porous loads, the condition for reliable, repeatable cycles. In a sector where sterilization is a critical step, running it regularly and documenting the results protects both product quality and regulatory compliance. Equipment designed with built-in test programs and native traceability makes this control a natural part of everyday operation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The Bowie-Dick test is a routine check that confirms a fractionated vacuum autoclave removes air completely from the chamber and lets saturated steam penetrate evenly through porous loads. It is a functional check of the equipment, not a proof of sterility for an individual load. In steam sterilization, trapped air is the most common reason [&hellip;]<\/p>\n","protected":false},"author":5,"featured_media":10418,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"inline_featured_image":false,"footnotes":""},"categories":[68],"tags":[],"class_list":["post-10421","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news-en"],"acf":[],"_links":{"self":[{"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/posts\/10421","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/comments?post=10421"}],"version-history":[{"count":1,"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/posts\/10421\/revisions"}],"predecessor-version":[{"id":10423,"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/posts\/10421\/revisions\/10423"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/media\/10418"}],"wp:attachment":[{"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/media?parent=10421"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/categories?post=10421"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lasttechnology.it\/en\/wp-json\/wp\/v2\/tags?post=10421"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}