{"id":100232,"date":"2026-06-22T12:46:35","date_gmt":"2026-06-22T12:46:35","guid":{"rendered":"http:\/\/www.irwin.com.hk\/zh_cn\/case-studies\/dn1000-scrubber-drain-renewal\/"},"modified":"2026-06-22T12:48:36","modified_gmt":"2026-06-22T12:48:36","slug":"dn1000-scrubber-drain-renewal","status":"publish","type":"page","link":"https:\/\/www.irwin.com.hk\/zh_cn\/case-studies\/dn1000-scrubber-drain-renewal\/","title":{"rendered":"DN1000 Scrubber Drain Renewal Without Drydock"},"content":{"rendered":"<style>\n.irwin-case{font-family:Inter,Arial,sans-serif;color:#102033;line-height:1.62;max-width:1120px;margin:0 auto;padding:56px 22px 72px}.irwin-case h1{font-size:clamp(34px,4vw,58px);line-height:1.04;color:#092840;margin:0 0 18px;font-weight:800;letter-spacing:0}.irwin-case h2{font-size:clamp(24px,2.2vw,34px);color:#0a2942;margin:48px 0 16px;font-weight:800}.irwin-case h3{font-size:20px;color:#0a2942;margin:24px 0 8px;font-weight:800}.irwin-case p{font-size:18px;margin:0 0 18px}.irwin-kicker{color:#f26a21;text-transform:uppercase;font-weight:800;letter-spacing:.08em;font-size:14px;margin-bottom:14px}.irwin-lede{font-size:22px!important;color:#26384f;max-width:920px}.irwin-stats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;margin:32px 0}.irwin-stat{background:#0a2942;color:#fff;border-radius:8px;padding:22px}.irwin-stat strong{display:block;font-size:28px;line-height:1.05;color:#fff}.irwin-stat span{display:block;color:#d9e6ef;margin-top:8px;font-size:14px}.irwin-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px;margin:20px 0}.irwin-card{border:1px solid #d7e0e8;border-radius:8px;padding:24px;background:#fff}.irwin-card ul{margin:0;padding-left:20px}.irwin-card li{font-size:17px;margin:8px 0}.irwin-table{width:100%;border-collapse:collapse;margin:18px 0 30px;font-size:16px}.irwin-table th,.irwin-table td{border:1px solid #d7e0e8;padding:13px;text-align:left;vertical-align:top}.irwin-table th{background:#eef3f7;color:#0a2942}.irwin-note{background:#f5f8fb;border-left:5px solid #f26a21;padding:20px 22px;border-radius:6px;margin:24px 0}.irwin-cta{background:#0a2942;color:#fff;border-radius:8px;padding:28px;margin-top:44px}.irwin-cta h2{color:#fff;margin-top:0}.irwin-cta p{color:#e5eef5}.irwin-cta a{display:inline-block;background:#f26a21;color:#fff;text-decoration:none;padding:12px 18px;border-radius:6px;font-weight:800;margin-top:6px}@media(max-width:760px){.irwin-stats,.irwin-grid{grid-template-columns:1fr}.irwin-case{padding-top:36px}.irwin-case p{font-size:16px}.irwin-lede{font-size:19px!important}}\n<\/style>\n<article class=\"irwin-case\">\n<div class=\"irwin-kicker\">Case Study \u00b7 EGCS \/ Scrubber Drain Renewal<\/div>\n<div class=\"irwin-page-title\" style=\"font-size:clamp(34px,4vw,58px);line-height:1.04;color:#092840;margin:0 0 18px;font-weight:800;letter-spacing:0;\">DN1000 Scrubber Drain Renewal Without Drydock<\/div>\n<p class=\"irwin-lede\">A large container vessel had a failed DN1000 exhaust-gas scrubber drain system. Irwin used Automet FAB to capture the as-built geometry, then renewed the failed GRE drain lines with temperature-matched lined carbon-steel spools and DN1000 duplex-stainless isolation valves.<\/p>\n<div class=\"irwin-stats\">\n<div class=\"irwin-stat\"><strong>DN1000<\/strong><span>large-bore scrubber drain scope<\/span><\/div>\n<div class=\"irwin-stat\"><strong>In service<\/strong><span>completed without drydocking for this scope<\/span><\/div>\n<div class=\"irwin-stat\"><strong>Automet FAB<\/strong><span>3D as-built digital-twin survey<\/span><\/div>\n<\/p><\/div>\n<h2>The Problem<\/h2>\n<p>The vessel&#8217;s GRE drain lines from the scrubber outlets were heat-damaged and leaking. One GRE spool had begun pulling out of its bonded flange, turning the drain system into a repeat-risk item rather than a simple like-for-like pipe replacement.<\/p>\n<p>The root operating issue was also addressed: the drain lines did not have isolation valves, which made it difficult to shut off hot, low-pH effluent during service.<\/p>\n<h2>What Irwin Did<\/h2>\n<div class=\"irwin-grid\">\n<div class=\"irwin-card\">\n<h3>Survey and modelling<\/h3>\n<ul>\n<li>Surveyed the failed drain system onboard with Automet FAB.<\/li>\n<li>Created a 3D as-built digital twin of the installed arrangement.<\/li>\n<li>Prepared the replacement geometry before fabrication began.<\/li>\n<\/ul>\n<\/div>\n<div class=\"irwin-card\">\n<h3>Temperature-matched materials<\/h3>\n<ul>\n<li>Used Halar-lined carbon steel for hotter sections.<\/li>\n<li>Used PE-lined carbon steel elsewhere in the drain system.<\/li>\n<li>Added four DN1000 duplex-stainless isolation valves.<\/li>\n<\/ul>\n<\/div><\/div>\n<p>The replacement spools were prefabricated ashore for bolt-in installation to the existing system. A riding team carried out the onboard renewal and re-supported the line scope by scope, with the work completed to the owner&#8217;s representative&#8217;s satisfaction.<\/p>\n<h2>Material Selection Guide<\/h2>\n<table class=\"irwin-table\">\n<thead>\n<tr>\n<th>Service temperature<\/th>\n<th>Recommended Irwin approach<\/th>\n<th>Reason<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Up to 70 C<\/td>\n<td>PE-lined carbon steel<\/td>\n<td>Polyethylene lining gives corrosion and erosion resistance while the steel carrier takes the mechanical load.<\/td>\n<\/tr>\n<tr>\n<td>70-160 C<\/td>\n<td>Halar-lined carbon steel<\/td>\n<td>ECTFE lining is used for hotter scrubber drain sections above polyethylene&#8217;s working range.<\/td>\n<\/tr>\n<tr>\n<td>Above 160 C<\/td>\n<td>SMO254 or solid alloy<\/td>\n<td>For the hottest sections, material selection shifts to suitable alloy construction rather than polymer lining.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div class=\"irwin-note\"><strong>Why replace GRE with lined carbon steel?<\/strong> GRE is selected for corrosion resistance, but bonded joints can be vulnerable under mechanical load. PE-lined or Halar-lined carbon steel keeps the corrosion barrier while the steel carrier provides far greater mechanical strength \u2014 over ten times the tensile strength of GRE.<\/div>\n<h2>Why This Matters For Similar Vessels<\/h2>\n<p>For owners with recurring scrubber drain leaks, replacing the same material like for like may leave the underlying failure mode untouched. A better renewal strategy starts with the service conditions: temperature, effluent chemistry, mechanical loading, support arrangement and whether the line can be isolated.<\/p>\n<p>For this vessel, Irwin matched the lining to the operating temperature, added isolation capability, and delivered a prefabricated bolt-in renewal that avoided a dockyard dependency for this scope.<\/p>\n<h2>FAQ<\/h2>\n<h3>Can scrubber drain lines be renewed without drydocking?<\/h3>\n<p>For some scopes, yes. This DN1000 scrubber drain renewal was completed in service by a riding team using prefabricated bolt-in spools. Feasibility depends on access, isolation, support, class requirements and the specific line arrangement.<\/p>\n<h3>When should PE-lined carbon steel be used for scrubber drains?<\/h3>\n<p>PE-lined carbon steel is suitable for many wash-water and drain-line sections up to 70 C. Hotter sections may require Halar-lined carbon steel, SMO254 or another solid alloy solution.<\/p>\n<h3>Why replace GRE with lined carbon steel?<\/h3>\n<p>GRE provides corrosion resistance but can be vulnerable at bonded joints under mechanical load. Lined carbon steel uses steel for mechanical strength while the lining provides the corrosion barrier.<\/p>\n<h3>Why add isolation valves?<\/h3>\n<p>The source case noted that the drain lines lacked isolation valves. Adding isolation valves helped address operating control of the drain system, not only the visible failed spool.<\/p>\n<h3>What does Automet FAB add to this kind of job?<\/h3>\n<p>Automet FAB captures the as-built geometry so replacement spools can be prefabricated for the installed arrangement, reducing guesswork during onboard fitting.<\/p>\n<div class=\"irwin-cta\">\n<h2>Have a scrubber drain or GRE pipe failure?<\/h2>\n<p>Irwin can review the line arrangement, service temperature and repair window, then propose a prefabricated lined-steel renewal scope.<\/p>\n<p><a href=\"https:\/\/www.irwin.com.hk\/consultation\/\">Book a technical consultation<\/a><\/div>\n<\/article>\n<p><script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"Can scrubber drain lines be renewed without drydocking?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"For some scopes, yes. 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