{"id":2712,"date":"2021-02-02T09:30:00","date_gmt":"2021-02-02T09:30:00","guid":{"rendered":"https:\/\/asturmadidoors.visualit.com.es\/clearances-around-the-fire-door\/"},"modified":"2026-08-20T10:45:02","modified_gmt":"2026-08-20T10:45:02","slug":"a-fire-doors-upper-and-lower-gaps","status":"publish","type":"post","link":"https:\/\/asturmadidoors.visualit.com.es\/en\/blog\/a-fire-doors-upper-and-lower-gaps\/","title":{"rendered":"A fire door&#8217;s upper and lower gaps"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"594\" height=\"841\" src=\"https:\/\/asturmadidoors.visualit.com.es\/wp-content\/uploads\/2026\/07\/017-Plano-No-13-Seccion-Vertical-Pta-Senc_001.webp\" alt=\"\" class=\"wp-image-1821\" srcset=\"https:\/\/asturmadidoors.visualit.com.es\/wp-content\/uploads\/2026\/07\/017-Plano-No-13-Seccion-Vertical-Pta-Senc_001.webp 594w, https:\/\/asturmadidoors.visualit.com.es\/wp-content\/uploads\/2026\/07\/017-Plano-No-13-Seccion-Vertical-Pta-Senc_001-212x300.webp 212w\" sizes=\"(max-width: 594px) 100vw, 594px\" \/><\/figure>\n\n<p class=\"wp-block-paragraph\">According to the <strong>EN 1363-1:2012<\/strong> standard, the formula for calculating the clearances required for a fire door to function optimally is <strong>X = (a + b) \/ 2 + 2 mm<\/strong>, where \u201ca\u201d is the maximum clearance and \u201cb\u201d is the average clearance.<\/p>\n\n<p class=\"wp-block-paragraph\">Contrary to what one might think, it is not necessary to seal the bottom of the door to prevent flames and smoke from entering the protected area.<\/p>\n\n<p class=\"wp-block-paragraph\">Due to the very nature of the fire, the flames exert pressure on the upper two-thirds of the door. The lower opening allows air to flow toward the fire, not away from it. <\/p>\n\n<p class=\"wp-block-paragraph\">Therefore, it is acceptable to install fire doors with a small gap at the bottom between the floor and the door leaf. This gap is necessary to prevent the door leaf from catching on the floor, which would interfere with the proper operation of the door closer. <\/p>\n\n<p class=\"wp-block-paragraph\">Despite this, it is not advisable for the gaps to exceed the maximum allowed, since this would increase the supply of oxidizing agent\u2014that is, oxygen\u2014to the fire. This is undesirable because it helps the fire grow and creates even more unsafe conditions during the fire. <\/p>\n\n<p class=\"wp-block-paragraph\">View the ASTURMADI FIRESTOP technical data sheet at<br\/><\/p>\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/asturmadidoors.visualit.com.es\/wp-content\/uploads\/2026\/07\/Asturmadi-ESTANDAR-FT.pdf\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/asturmadidoors.visualit.com.es\/wp-content\/uploads\/2026\/07\/Asturmadi-ESTANDAR-FT.pdf<\/a><\/p>\n\n<p class=\"wp-block-paragraph\">Write to us at<br\/>using the contact form<\/p>\n\n<p class=\"wp-block-paragraph\"><a href=\"\/productos\/\">Contact Us<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The clearances in single-leaf fire doors between the door and the floor, and between the door and the top frame, required for the door to function optimally, are as follows:<\/p>\n","protected":false},"author":1,"featured_media":2713,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[57,75],"tags":[],"class_list":["post-2712","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-instalacion-puertas-cortafuegoprofesional","category-professional-installation"],"acf":[],"_links":{"self":[{"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/posts\/2712","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/comments?post=2712"}],"version-history":[{"count":0,"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/posts\/2712\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/media\/2713"}],"wp:attachment":[{"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/media?parent=2712"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/categories?post=2712"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/asturmadidoors.visualit.com.es\/en\/wp-json\/wp\/v2\/tags?post=2712"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}