{"id":7790,"date":"2025-10-04T09:00:00","date_gmt":"2025-10-04T08:00:00","guid":{"rendered":"https:\/\/uplastech.com\/pe-rt-pipe-extrusion\/"},"modified":"2026-10-28T09:22:19","modified_gmt":"2026-10-28T09:22:19","slug":"pe-rt-pipe-extrusion","status":"publish","type":"post","link":"https:\/\/uplastech.com\/it\/pe-rt-pipe-extrusion\/","title":{"rendered":"PE-RT Pipe Extrusion: Floor Heating Tube Without Crosslinking"},"content":{"rendered":"<style>\n.upl-blog{font-size:17px;line-height:1.78;color:#1f2937}\n.upl-blog p{margin:0 0 18px}\n.upl-blog h2{font-size:26px;line-height:1.3;color:#0b2b33;margin:46px 0 14px;font-weight:700;letter-spacing:-.015em}\n.upl-blog h3{font-size:19.5px;color:#0d3b47;margin:28px 0 10px;font-weight:700}\n.upl-blog ul,.upl-blog ol{margin:0 0 20px;padding-left:22px}\n.upl-blog li{margin:0 0 9px}\n.upl-blog figure{margin:0 0 34px}\n.upl-blog figure img{width:100%;height:auto;display:block;border-radius:10px}\n.upl-blog figcaption{font-size:13px;color:#6b7280;margin-top:10px;line-height:1.5}\n.upl-blog .toc{background:none;border:0;border-radius:0;padding:0;margin:0 0 34px}\n.upl-blog .toc .lwptoc{margin:0}\n.upl-blog .toc h4{margin:0 0 10px;font-size:13px;letter-spacing:.1em;text-transform:uppercase;color:#0d5563}\n.upl-blog .toc ol{margin:0;padding-left:18px;font-size:14.5px}\n.upl-blog .toc li{margin-bottom:6px}\n.upl-blog table{width:100%;border-collapse:collapse;font-size:14.5px;margin:0 0 10px}\n.upl-blog th{background:#0d3b47;color:#fff;text-align:left;padding:11px 13px;font-weight:600;font-size:13.5px;border:0}\n.upl-blog td{padding:11px 13px;border:0;border-bottom:1px solid #e8ebed;vertical-align:top}\n.upl-blog tbody tr:nth-child(even){background:#fafbfc}\n.upl-blog .tablecap{font-size:12.5px;color:#6b7280;margin:0 0 30px}\n.upl-blog .myth{background:#fff8ef;border:1px solid #f6ddbd;border-radius:8px;padding:16px 20px;margin:0 0 26px;font-size:15.5px}\n.upl-blog .myth b{color:#a85c10}\n.upl-blog .callout{background:#f2f8f9;border-radius:8px;padding:18px 22px;margin:0 0 26px;font-size:15.5px;border-left:3px solid #14707f}\n.upl-blog .faq h3{border-top:1px solid #eceff1;padding-top:22px;margin-top:0;font-size:18px}\n.upl-blog .faq h3:first-of-type{border-top:0;padding-top:0}\n.upl-blog .cta{background:linear-gradient(135deg,#0b2b33,#0d5563);color:#fff;border-radius:12px;padding:34px;margin:48px 0 30px}\n.upl-blog .cta h2,.upl-blog .cta .cta-h{color:#fff;margin:0 0 10px;font-size:24px;font-weight:700;line-height:1.3}\n.upl-blog .cta p{color:#c9dee3;margin:0 0 20px;font-size:16px}\n.upl-blog .btn{display:inline-block;background:#e07a1f;color:#fff;text-decoration:none;font-weight:700;padding:13px 26px;border-radius:8px;font-size:15.5px}\n.upl-blog .rel{border-top:1px solid #e8ebed;margin-top:40px;padding-top:26px}\n.upl-blog .rel h4{font-size:13px;letter-spacing:.1em;text-transform:uppercase;color:#6b7280;margin:0 0 14px}\n.upl-blog .rel ul{list-style:none;padding:0;margin:0}\n.upl-blog .rel li{padding:11px 0;border-bottom:1px dashed #e8ebed}\n.upl-blog .rel a{text-decoration:none;font-weight:600;font-size:15.5px}\n@media(max-width:640px){.upl-blog h2{font-size:22px}.upl-blog table{font-size:13px}.upl-blog .cta{padding:24px}}\n\/* \u5355\u7bc7\u9875\u9690\u85cf WhatsApp \u95ee\u5019\u5361\uff0c\u53ea\u4fdd\u7559\u5706\u5f62\u6c14\u6ce1\uff0c\u907f\u514d\u906e\u6321\u4fa7\u680f\u8be2\u76d8\u63d0\u4ea4\u6309\u94ae\u3002\n   \u6ce8\u610f\uff1aClick to Chat \u7684\u70b9\u51fb\u903b\u8f91\u662f\u300c\u95ee\u5019\u5361\u5143\u7d20\u5b58\u5728\u5c31\u4e0d\u8df3\u8f6c\u300d\uff0c\u53ea\u9760 CSS \u9690\u85cf\u4f1a\u8ba9\u6c14\u6ce1\u53d8\u6210\u6b7b\u94fe\u63a5\u3002\n   Code Snippets #9\u300cUPL single post: WhatsApp bubble jumps straight to chat\u300d\u8d1f\u8d23\u628a\u8be5\u8282\u70b9\u4ece DOM \u79fb\u9664\uff0c\n   \u4e0b\u9762\u8fd9\u6761 CSS \u53ea\u662f\u79fb\u9664\u524d\u7684\u89c6\u89c9\u515c\u5e95\u3002\u5220 #9 \u524d\u5fc5\u987b\u5148\u5220\u8fd9\u6761\u89c4\u5219\u3002 *\/\nbody.single-post .ht_ctc_chat_greetings_box{display:none !important}\n<\/style>\n<div class=\"upl-blog\">\n<figure>\n<img fetchpriority=\"high\" decoding=\"async\" src=\"https:\/\/uplastech.com\/wp-content\/uploads\/2026\/10\/pe-rt-pipe-extrusion.jpg\" alt=\"PE-RT and PEX pressure derating curves and wall thickness by SDR for 20 mm pipe\" width=\"1536\" height=\"909\"><figcaption>Up to 70 \u00b0C the two curves are close. Above it, crosslinking earns its cost.<\/figcaption><\/figure>\n<div class=\"toc\"><\/div>\n<h2 id=\"what\">What PE-RT is<\/h2>\n<p>PE-RT is polyethylene of raised temperature resistance. It is a copolymer of ethylene with a small amount of a higher alpha-olefin, arranged so that the comonomer sits on the long chain rather than in short branches. That arrangement raises the melting point and, more importantly, changes how the material behaves under long-term stress at temperature.<\/p>\n<p>The result is a polyethylene that holds a hydrostatic rating at 70 \u00b0C for 50 years without crosslinking. PEX achieves the same by joining the chains chemically; PE-RT achieves it by controlling the chain architecture. Both work, and the difference is in everything else.<\/p>\n<p>Because PE-RT is not crosslinked, it can be recycled, it can be fusion welded like any polyethylene, and it is easier to extrude because there is no crosslinking step. It is also less resistant to very high temperature and to some chemical environments than PEX.<\/p>\n<table>\n<thead>\n<tr>\n<th>Grade<\/th>\n<th>Design stress at 20 \u00b0C<\/th>\n<th>Maximum service<\/th>\n<th>Typical use<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>PE-RT Type I<\/td>\n<td>6.3 MPa<\/td>\n<td>70 \u00b0C continuous<\/td>\n<td>Floor heating, domestic water<\/td>\n<\/tr>\n<tr>\n<td>PE-RT Type II<\/td>\n<td>8.0 MPa<\/td>\n<td>70 \u00b0C at higher pressure<\/td>\n<td>Larger systems, higher heads<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 1 \u2014 PE-RT grades. Type II is a higher-performance polymer and is specified where the same diameter must carry more pressure.<\/p>\n<h2 id=\"rating\">The rating, and how it compares with PEX<\/h2>\n<p>Both PE-RT and PEX are rated at 20 \u00b0C and both derate with temperature. The curves are close up to about 70 \u00b0C and diverge above it. At 70 \u00b0C a PN16 PE-RT pipe is good for about 8.5 bar against 9.9 for PEX-a; at 80 \u00b0C the gap widens to 7.2 against 8.6.<\/p>\n<p>For floor heating, which runs at 35 to 50 \u00b0C, the difference is irrelevant. For radiator systems at 70 to 80 \u00b0C it is worth checking. For anything above 80 \u00b0C, PEX or a different material is the right choice.<\/p>\n<p>The advantage PE-RT has is not in the rating but in the installation. Because it is a thermoplastic rather than a crosslinked one, it can be joined by fusion welding, it can be recycled at end of life, and a damaged section can be cut out and re-jointed on site. PEX needs mechanical fittings and cannot be fusion welded.<\/p>\n<table>\n<thead>\n<tr>\n<th>Temperatura<\/th>\n<th>PE-RT PN16<\/th>\n<th>PEX-a PN16<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>20 \u00b0C<\/td>\n<td>16.0 bar<\/td>\n<td>16.0 bar<\/td>\n<\/tr>\n<tr>\n<td>40 \u00b0C<\/td>\n<td>12.8 bar<\/td>\n<td>13.8 bar<\/td>\n<\/tr>\n<tr>\n<td>60 \u00b0C<\/td>\n<td>9.8 bar<\/td>\n<td>11.2 bar<\/td>\n<\/tr>\n<tr>\n<td>70 \u00b0C<\/td>\n<td>8.5 bar<\/td>\n<td>9.9 bar<\/td>\n<\/tr>\n<tr>\n<td>80 \u00b0C<\/td>\n<td>7.2 bar<\/td>\n<td>8.6 bar<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 2 \u2014 Allowable pressure against temperature. Below 60 \u00b0C the two are within 15 percent of each other.<\/p>\n<h2 id=\"extrusion\">Extrusion: easier than PEX, stricter than HDPE<\/h2>\n<p>PE-RT extrudes on standard PE equipment at 190 to 220 \u00b0C. There is no crosslinking step, no silane dosing, no electron beam \u2014 the pipe comes off the line finished, which is the main process advantage over PEX-b and PEX-c.<\/p>\n<p>The temperature profile should be slightly cooler than HDPE at the same wall, because PE-RT has a lower melting point and a narrower band between melting and degradation. 200 \u00b0C at the die is typical; 220 \u00b0C is the upper limit.<\/p>\n<p>Cooling is critical for a different reason than in HDPE. Floor heating tube is supplied in coils of 100 to 300 metres, and a coil must be round enough to uncoil without kinking. A pipe that is cooled too fast has residual stress that makes it coil unevenly, and the coil will have a memory that fights the installer.<\/p>\n<p>Sizing is by vacuum sleeve, and the shrinkage allowance is 1.5 to 2.5 percent, similar to HDPE. Because the wall is thin \u2014 a 20 mm SDR 6 pipe is 3.3 mm \u2014 the line runs fast and the tank is short.<\/p>\n<div class=\"callout\">Coiling tension is part of the process, not the packing department. A coil wound too tight will be oval at the inner end and the installer will cut off the first two metres of every coil.<\/div>\n<h2 id=\"dimensions\">Dimensions: the SDR system again<\/h2>\n<p>PE-RT uses the same SDR system as PPR and HDPE. A 20 mm SDR 6 pipe has a 3.3 mm wall and is rated PN20 at 20 \u00b0C. Floor heating tube is almost always 16 or 20 mm outside diameter, in SDR 6 or SDR 7.4.<\/p>\n<p>The dimension that matters most in practice is ovality, because the tube has to push through a clip, a manifold fitting or a screed without jamming. An oval tube also does not seal properly in a compression fitting, and a leaking manifold connection in a floor is a very expensive repair.<\/p>\n<table>\n<thead>\n<tr>\n<th>Size<\/th>\n<th>SDR<\/th>\n<th>Wall<\/th>\n<th>Typical use<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>16 mm<\/td>\n<td>SDR 6<\/td>\n<td>2.7 mm<\/td>\n<td>Floor heating, tight loops<\/td>\n<\/tr>\n<tr>\n<td>16 mm<\/td>\n<td>SDR 7.4<\/td>\n<td>2.2 mm<\/td>\n<td>Floor heating, lower pressure<\/td>\n<\/tr>\n<tr>\n<td>20 mm<\/td>\n<td>SDR 6<\/td>\n<td>3.3 mm<\/td>\n<td>Floor heating, main runs<\/td>\n<\/tr>\n<tr>\n<td>20 mm<\/td>\n<td>SDR 7.4<\/td>\n<td>2.7 mm<\/td>\n<td>Domestic water<\/td>\n<\/tr>\n<tr>\n<td>25 mm<\/td>\n<td>SDR 7.4<\/td>\n<td>3.4 mm<\/td>\n<td>Small distribution mains<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 3 \u2014 Common PE-RT sizes. Floor heating is dominated by 16 and 20 mm.<\/p>\n<h2 id=\"heating\">Floor heating: what the tube has to do<\/h2>\n<p>A floor heating loop is a tube buried in screed, carrying water at 35 to 50 \u00b0C, that must last the life of the building without a joint under the floor. There is no maintenance access, so the tube is specified for 50 years and the joint is designed out.<\/p>\n<p>That means the coil must be joint-free, the tube must be oxygen-barrier if the system has metal components, and the bend radius must be respected during installation. A PE-RT tube with an EVOH oxygen barrier layer is standard for systems with steel radiators or boilers, because oxygen diffusing through the tube corrodes the metal.<\/p>\n<p>The barrier layer is coextruded, usually 0.1 to 0.2 mm of EVOH on the outside. It is thin, it is not structural, and it is easily damaged by a sharp clip or a careless pull through a stud. A barrier tube with a scratch through the EVOH has no barrier at that point.<\/p>\n<div class=\"myth\"><b>\"Oxygen barrier is only for closed systems.\"<\/b> The barrier protects the metal in the system from oxygen entering through the tube wall. Any system with steel or iron components needs it, whether it is described as closed or not.<\/div>\n<h2 id=\"testing\">Testing and the checks that matter<\/h2>\n<p>PE-RT pipe is tested by hydrostatic pressure at 20, 60 and 95 \u00b0C, and the results are extrapolated to 50 years. The 95 \u00b0C test is the one that separates a genuine PE-RT from a standard PE that has been relabelled.<\/p>\n<p>On the line, the checks are dimensional: outside diameter, wall thickness, ovality and length. A laser gauge at the haul-off gives a continuous record and catches drift before it becomes a coil of scrap.<\/p>\n<p>For floor heating, the installation test is a pressure test before the screed is poured and a second one after. A tube that passes before and fails after has been damaged by the screed work, and the repair is a joint under the floor that the specification was designed to avoid.<\/p>\n<div class=\"faq\">\n<h3>What does PE-RT stand for?<\/h3>\n<p>Polyethylene of raised temperature resistance. It is a polyethylene copolymer that holds a hydrostatic pressure rating at 70 \u00b0C without crosslinking.<\/p>\n<h3>Is PE-RT as good as PEX for floor heating?<\/h3>\n<p>For floor heating at 35 to 50 \u00b0C, yes, and it has advantages: it can be fusion welded, it is recyclable, and it needs no crosslinking step. Above 80 \u00b0C PEX has the higher rating.<\/p>\n<h3>Can PE-RT pipe be fusion welded?<\/h3>\n<p>Yes. It is a thermoplastic, not a crosslinked polymer, so it can be butt-fused or socket-fused like any polyethylene. PEX cannot.<\/p>\n<h3>What is the maximum temperature for PE-RT?<\/h3>\n<p>70 \u00b0C continuous for Type I, with short excursions higher. Above 80 \u00b0C the derating becomes severe and PEX or a different material is the better choice.<\/p>\n<h3>Does floor heating tube need an oxygen barrier?<\/h3>\n<p>If the system contains steel, iron or a boiler, yes. Oxygen diffusing through the tube wall corrodes the metal components. The barrier is a thin coextruded EVOH layer.<\/p>\n<h3>What is the difference between PE-RT Type I and Type II?<\/h3>\n<p>Type II has a higher design stress, 8.0 MPa against 6.3, which means the same diameter carries more pressure at the same temperature. It costs more and is specified where the system head demands it.<\/p>\n<\/div>\n<div class=\"cta\">\n<p class=\"cta-h\">Extruding PE-RT tube for floor heating?<\/p>\n<p>Tell us the diameter, the SDR and whether the tube needs an oxygen barrier. We will size the line and tell you where the ovality will come from.<\/p>\n<p><a class=\"btn\" href=\"https:\/\/uplastech.com\/it\/estrusioni-di-tubi\/\">Talk to a pipe extrusion engineer<\/a>\n<\/div>\n<div class=\"rel\">\n<h4>Continue reading<\/h4>\n<ul>\n<li><a href=\"https:\/\/uplastech.com\/it\/hdpe-pipe-extrusion\/\">HDPE Pipe Extrusion: Sag, Ovality and Cooling<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/it\/ppr-pipe-extrusion\/\">PPR Pipe Extrusion: Grades and Derating<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/it\/pvc-pipe-ring-stiffness-impact\/\">PVC Pipe Ring Stiffness and Impact<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/it\/multilayer-pipe-coextrusion\/\">Multilayer Pipe Coextrusion<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/it\/sizing-sleeves-and-calibrators\/\">Sizing Sleeves and Calibrators<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>PE-RT is a polyethylene that holds its pressure rating at 70 \u00b0C without being crosslinked. That one property makes it recyclable, weldable and cheaper to make than PEX.<\/p>","protected":false},"author":1,"featured_media":7789,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"PE-RT Pipe Extrusion: Grades, Rating and Floor Heating","_seopress_titles_desc":"PE-RT pipe extrusion guide: Type I and II grades, the derating curve against PEX, extrusion settings, SDR dimensions and floor heating requirements.","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"17","_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":"","footnotes":""},"categories":[17],"tags":[],"class_list":["post-7790","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-plastic-extrusion-process"],"meta_box":{"post-to-quiz_to":[]},"_links":{"self":[{"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/posts\/7790","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/comments?post=7790"}],"version-history":[{"count":1,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/posts\/7790\/revisions"}],"predecessor-version":[{"id":7859,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/posts\/7790\/revisions\/7859"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/media\/7789"}],"wp:attachment":[{"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/media?parent=7790"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/categories?post=7790"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/tags?post=7790"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}