{"id":325,"date":"2026-09-08T07:40:01","date_gmt":"2026-09-08T07:40:01","guid":{"rendered":"https:\/\/fenggu-bio.com\/isolator-hvac-operating-modes\/"},"modified":"2026-09-08T07:40:01","modified_gmt":"2026-09-08T07:40:01","slug":"isolator-hvac-operating-modes","status":"publish","type":"post","link":"https:\/\/fenggu-bio.com\/ru\/isolator-hvac-operating-modes\/","title":{"rendered":"Isolator HVAC Design: The Four Operating Modes (and Passive vs Active RABS)"},"content":{"rendered":"<style>\n.entry-title,.ast-single-post .entry-header{display:none!important}\n.fg-art{font-family:-apple-system,BlinkMacSystemFont,\"Segoe UI\",Roboto,\"Helvetica Neue\",Arial,sans-serif;color:#1e2838;line-height:1.72;max-width:820px;margin:0 auto;padding:0 22px;font-size:16.5px}\n.fg-art .fg-eyebrow{display:inline-block;background:#e3ecfa;color:#003AA1;font-weight:700;font-size:12px;letter-spacing:.7px;padding:5px 13px;border-radius:20px;text-transform:uppercase;margin:34px 0 14px}\n.fg-art h1{font-size:33px;line-height:1.2;color:#002B78;margin:0 0 12px;font-weight:800}\n.fg-art .meta{font-size:13.5px;color:#7a8699;margin:0 0 26px;border-bottom:1px solid #e6ebf3;padding-bottom:18px}\n.fg-art h2{font-size:23px;color:#002B78;margin:38px 0 12px;line-height:1.28}\n.fg-art p{margin:0 0 16px}\n.fg-art .lead{font-size:18px;color:#3a4658}\n.fg-art figure{margin:26px 0}\n.fg-art img{width:100%;border-radius:12px;box-shadow:0 6px 22px rgba(0,58,161,.12);display:block}\n.fg-art figcaption{font-size:13px;color:#7a8699;margin-top:9px;text-align:center}\n.fg-art table{border-collapse:collapse;width:100%;margin:22px 0;font-size:14.5px}\n.fg-art th,.fg-art td{border:1px solid #d7dfea;padding:11px 14px;text-align:left;vertical-align:top}\n.fg-art thead th{background:#002B78;color:#fff;font-weight:700}\n.fg-art tbody th{background:#eff4fb;color:#002B78;font-weight:700;width:24%}\n.fg-art tbody tr:nth-child(even) td{background:#f7f9fc}\n.fg-art ul{margin:0 0 16px;padding-left:22px}.fg-art li{margin:7px 0}\n.fg-art .fg-cta{background:linear-gradient(120deg,#002B78,#003AA1);color:#fff;border-radius:14px;padding:30px 28px;margin:38px 0 10px;text-align:center}\n.fg-art .fg-cta h3{color:#fff;font-size:22px;margin:0 0 8px}\n.fg-art .fg-cta p{color:#dce7f7;margin:0 0 18px;font-size:15.5px}\n.fg-art .fg-btn{display:inline-block;background:#EC001B;color:#fff;padding:13px 28px;border-radius:6px;font-weight:600;font-size:15.5px;text-decoration:none;margin:0 6px 8px}\n.fg-art .fg-btn.o{background:transparent;border:2px solid rgba(255,255,255,.7)}\n.fg-art a{color:#003AA1;text-decoration:underline}\n.fg-art .fg-cta a{text-decoration:none;color:#fff}\n@media(max-width:640px){.fg-art h1{font-size:26px}.fg-art th,.fg-art td{padding:9px 10px;font-size:13.5px}.fg-art tbody th{width:34%}}\n<\/style>\n<article class=\"fg-art\">\n<span class=\"fg-eyebrow\">Barrier Systems &middot; HVAC<\/span><\/p>\n<h1>Isolator HVAC Design: The Four Operating Modes (and Passive vs Active RABS)<\/h1>\n<div class=\"meta\">By Fenggu Medical Equipment &middot; Pharmaceutical Isolation &amp; Containment<\/div>\n<p class=\"lead\">Choosing between an isolator and a RABS is only the first decision &mdash; the barrier you pick then drives the design of your HVAC and control system. An isolator cycles through four distinct HVAC operating modes, while a RABS effectively runs in one. This guide explains each mode, how passive and active RABS connect to the air system, and the airflow best practices that keep a Grade A \/ ISO 5 zone reliable.<\/p>\n<figure>\n<img width=\"900\" height=\"675\" decoding=\"async\" src=\"\/wp-content\/uploads\/site\/cutout-af.jpg\" alt=\"Fenggu aseptic filling isolator with an integrated HVAC and VHP bio-decontamination system\"><figcaption>An isolator manages its own air through four HVAC modes; a RABS draws on the room&#8217;s HVAC.<\/figcaption><\/figure>\n<p>New to the isolator-versus-RABS decision itself? Start with our overview, <a href=\"\/ru\/isolator-vs-rabs\/\">Isolator vs RABS for aseptic filling<\/a>, then come back here for the HVAC detail.<\/p>\n<h2>Why the barrier choice drives HVAC design<\/h2>\n<p>Open filling under unidirectional airflow (UAF) with mechanical guards or curtains cannot reliably isolate an exposed sterile product during operator intervention. A barrier system keeps the operator outside the critical zone, with interventions made through glove ports, rapid transfer ports (RTPs) or robotics. How that barrier exchanges air with the room &mdash; and whether it decontaminates itself &mdash; determines what the HVAC system has to do.<\/p>\n<h2>The four HVAC operating modes of an isolator<\/h2>\n<p>Unlike a simple cleanroom terminal, an isolator moves between four defined HVAC states across a production cycle:<\/p>\n<table>\n<thead>\n<tr>\n<th>Mode<\/th>\n<th>What happens<\/th>\n<th>Purpose<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<th>Outflow<\/th>\n<td>HEPA-filtered air flows through the critical zone and out through open doors into the surrounding room.<\/td>\n<td>Dust settling, cleaning and equipment set-up.<\/td>\n<\/tr>\n<tr>\n<th>\u0414\u0435\u0437\u0430\u043a\u0442\u0438\u0432\u0430\u0446\u0438\u044f<\/th>\n<td>The isolator is held airtight to the room while gaseous sterilant (VHP) is recirculated inside.<\/td>\n<td>Validated bio-decontamination of the enclosure.<\/td>\n<\/tr>\n<tr>\n<th>\u0410\u044d\u0440\u0430\u0446\u0438\u044f<\/th>\n<td>HEPA-filtered air flows out and is discharged through an exhaust.<\/td>\n<td>Stripping residual sterilant down to a safe level.<\/td>\n<\/tr>\n<tr>\n<th>\u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f<\/th>\n<td>HEPA-filtered air flows into the surrounding room through the mouseholes.<\/td>\n<td>Maintaining Grade A \/ ISO 5 during aseptic processing.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Whether the air comes from a dedicated air handling unit (AHU) or from the surrounding room, the AHU capacity, controls and &mdash; critically &mdash; its response to these mode changes all have to be engineered for the transitions between states. The bio-decontamination step behind &#8220;Decontamination&#8221; and &#8220;Aeration&#8221; mode is explained in <a href=\"\/ru\/what-is-vhp-decontamination\/\">What Is VHP Decontamination<\/a>.<\/p>\n<h2>RABS and HVAC: passive vs active<\/h2>\n<p>From an HVAC point of view a RABS has essentially one operating mode. But the two basic RABS types connect to the air system in different ways:<\/p>\n<ul>\n<li><strong>Passive RABS<\/strong> &mdash; takes HEPA-filtered air directly from the facility&#8217;s ceiling-mounted HEPA terminals to maintain the Grade A \/ ISO 5 zone. It has no fans of its own.<\/li>\n<li><strong>Active RABS<\/strong> &mdash; draws room supply air and recirculates it through its own HEPA filters into the Grade A zone, then releases it back into the room below working height.<\/li>\n<\/ul>\n<h2>Airflow best practices that make &mdash; or break &mdash; performance<\/h2>\n<ul>\n<li><strong>Return air low, not high.<\/strong> For both passive and active RABS, air should leave the room through low-level return grilles, not high-mounted side inlets on the unit. High-mounted inlets on some active RABS can seriously disturb the airflow pattern around the unit.<\/li>\n<li><strong>Model it with CFD.<\/strong> Computational fluid dynamics (CFD) modelling is recommended to confirm the airflow pattern behaves as intended before the system is built.<\/li>\n<li><strong>Avoid large cleaning gaps in passive RABS.<\/strong> Big openings between panels let air cross the gap and can draw Grade B \/ ISO 7 air into the Grade A \/ ISO 5 zone. A close-fitting but demountable top panel &mdash; sealing to the ceiling system yet removable for filter testing and replacement &mdash; is best practice; a gap between panel and ceiling lets Grade B air migrate through the space between HEPA filters into Grade A.<\/li>\n<li><strong>Protect the door zone.<\/strong> The area around RABS doors should be protected by an enhanced local environment (e.g. LP\/GAAS) so contaminants are controlled during cleaning or open-door interventions.<\/li>\n<\/ul>\n<h2>Don&#8217;t forget the background environment<\/h2>\n<p>Both isolators and RABS are typically operated within a Grade B \/ ISO 7 background, and the whole scheme still depends on a correctly classified cleanroom &mdash; see <a href=\"\/ru\/iso-14644-cleanroom-classification\/\">ISO 14644-1 cleanroom classification<\/a>. For personalized, small-batch therapies such as cell and gene therapy, barrier-protected filling &mdash; often isolator-based &mdash; is increasingly the norm even for single-patient batches.<\/p>\n<div class=\"fg-cta\">\n<h3>Designing the HVAC around your barrier system?<\/h3>\n<p>Tell us your process and cleanroom layout, and our engineers will help specify the isolator or RABS airflow scheme &mdash; modes, AHU sizing and controls &mdash; that fits your validation requirements.<\/p>\n<p><a class=\"fg-btn\" href=\"\/ru\/products\/aseptic-filling-isolator\/\">View Isolators<\/a><br \/>\n<a class=\"fg-btn o\" href=\"\/ru\/contact\/\">Talk to an Engineer<\/a>\n<\/div>\n<\/article>","protected":false},"excerpt":{"rendered":"<p>Barrier Systems &middot; HVAC Isolator HVAC Design: The Four Operating Modes (and Passive vs Active RABS) By Fenggu Medical Equipment [&hellip;]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","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":"","ast-disable-related-posts":"","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":"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":"","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-4)","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-4)","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-4)","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":""},"categories":[1],"tags":[],"class_list":["post-325","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/posts\/325","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/comments?post=325"}],"version-history":[{"count":0,"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/posts\/325\/revisions"}],"wp:attachment":[{"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/media?parent=325"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/categories?post=325"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/tags?post=325"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}