{"id":239,"date":"2017-11-10T06:02:16","date_gmt":"2017-11-10T06:02:16","guid":{"rendered":"http:\/\/www.nafi.org\/blog\/?p=239"},"modified":"2018-01-09T16:00:33","modified_gmt":"2018-01-09T16:00:33","slug":"arc-mapping-new-science-or-new-myth","status":"publish","type":"post","link":"https:\/\/www.nafi.org\/blog\/arc-mapping-new-science-or-new-myth\/","title":{"rendered":"Arc Mapping: New Science or New Myth?"},"content":{"rendered":"

There has been a lot of debate in fire investigation industry recently regarding Arc Mapping. \u00a0NAFI’s mission is to increase the knowledge and improve the skills of persons engaged in the investigation and analysis of fires, explosions and arsons, or the litigation that ensues from such investigations.\u00a0The opinions expressed in this paper do not necessarily reflect the opinion and beliefs of NAFI. Over the next three weeks, we will be sharing different views on Arc Mapping with our members and the industry – it is up to you to draw your own conclusions.<\/em><\/p>\n

Week 1 – Arc Mapping: New Science or New Myth?
\nWeek 2 – Arc Mapping as a Tool for Fire Investigations<\/a>
\nWeek 3 \u2013 Arc Mapping: A Review of Findings<\/a><\/p>\n

Vytenis Babrauskas
\nFire Science and Technology Inc., San Diego, CA
\nDept. of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA<\/p>\n

ABSTRACT
\nArc mapping was first introduced in the 2001 edition of NFPA 921 and was subsequently expanded so that in the\u00a0recent editions it constitutes one of the four main methods for determining the origin of a fire. Careful consideration\u00a0of engineering principles and large-scale experimental studies on the subject indicates that the relevance and\u00a0prominence of arc mapping as a leading indicator of fire origin is greatly overstated. The technique is valid and\u00a0applicable only in some very limited scenarios. Yet it has seen very extensive use in recent years by investigators\u00a0preparing fire reports. In many cases, such attempted use of arc mapping is based on incorrect and invalid\u00a0hypotheses, which are often implicitly assumed to be true instead of being explicitly stated. The following are\u00a0myths: (i) An abundance of arc beads at a given locale means that fire originated in that area, while a paucity of arc\u00a0beads indicates that it did not. (ii) When multiple arcs are present on a circuit, the direction of arcing will necessarily\u00a0proceed upstream towards the power source. (iii) If an appliance is the victim of a fire, internal arcing will be\u00a0primarily near the exterior of the unit, while arcing deep inside indicates a fire origin at that place. NFPA is urged to\u00a0revise NFPA 921 to eliminate arc mapping as one of the four main methods for establishing fire origin, and to\u00a0subsume it under the more general category of \u201cfire patterns.\u201d In addition, it is important that NFPA 921 reduce the\u00a0implied general utility of the method and provide more explicit information on its interpretation and its limitations\u00a0and on the circumstances under which it may be a valid method for assisting in the determination of the fire origin.<\/p>\n

Download the complete paper here<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

There has been a lot of debate in fire investigation industry recently regarding Arc Mapping. \u00a0NAFI’s mission is to increase the knowledge and improve the skills of persons engaged in the investigation and analysis of fires, explosions and arsons, or the litigation that ensues from such investigations.\u00a0The opinions expressed in this paper do not necessarily … Continue reading Arc Mapping: New Science or New Myth?<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":232,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12],"tags":[],"class_list":["post-239","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-fire-investigation-science"],"_links":{"self":[{"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/posts\/239","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/comments?post=239"}],"version-history":[{"count":0,"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/posts\/239\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/media\/232"}],"wp:attachment":[{"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/media?parent=239"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/categories?post=239"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nafi.org\/blog\/wp-json\/wp\/v2\/tags?post=239"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}