Spontaneous ignition of vertically oriented wood exposed to convection and time-dependent thermal radiation: experimental and analytical prediction

Spontaneous ignition of vertically oriented wood exposed to convection and time-dependent thermal radiation: experimental and analytical prediction | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Spontaneous ignition of vertically oriented wood exposed to convection and time-dependent thermal radiation: experimental and analytical prediction Li Yan, K.M. Liew, Lizhong Yang, Xiaoyu Ju This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9484483/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Spontaneous ignition of vertically oriented structural timber induced by transient heat flux and crosswind, which represents a prevalent incident in building fire scenarios, has received little attention in existing studies. This study utilized a self-designed experimental setup, employing five quadratic heat fluxes ( \(\:{\dot{q}}_{ex}^{{\prime\:}{\prime\:}}=a{t}^{2}\) , heat flux increasing rates ( \(\:a\) ): 0.10, 0.13, 0.18, 0.28, 0.40 W/m 2 s 2 ) and five crosswind conditions ( \(\:{U}_{\infty\:}\) = 0, 0.4, 0.8, 1.0, 1.2 m/s) to systematically investigate timber ignition characteristics under coupled transient thermal radiation and convection. Surface temperature, mass loss rate (MLR) and ignition time were measured and analyzed. Analytical solutions for transient surface temperature were derived via one-dimensional heat conduction theory and validated against the experimental data. Using the critical mass loss rate (13 g/m 2 s) as the ignition criterion, this study developed ignition time prediction methods applicable to time-dependent thermal radiation scenarios. Results indicate that both surface temperature and MLR are mainly driven by thermal radiation. The approximate solution for the surface temperature is more accurate than the asymptotic solution. An increase in heat flux increasing rate reduces ignition time by an average of 17.4%, while an increase in crosswind speed prolongs ignition time by an average of 3.9%. The theoretical model considering surface heat loss restricts ignition time prediction error to within 20%. Wood Ignition behavior Ignition time prediction Transient irradiation Crosswind Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 08 May, 2026 Reviewers agreed at journal 08 May, 2026 Reviewers invited by journal 06 May, 2026 Editor assigned by journal 06 May, 2026 Submission checks completed at journal 26 Apr, 2026 First submitted to journal 21 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9484483","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":639045193,"identity":"e0361509-4f5e-4226-b2a3-aa8246b1ecae","order_by":0,"name":"Li Yan","email":"","orcid":"","institution":"University of Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"Yan","suffix":""},{"id":639045194,"identity":"b4b977f9-0e61-4afd-81ee-2d978a551dd9","order_by":1,"name":"K.M. Liew","email":"","orcid":"","institution":"City University of Hong Kong","correspondingAuthor":false,"prefix":"","firstName":"K.M.","middleName":"","lastName":"Liew","suffix":""},{"id":639045195,"identity":"247501a9-acc9-4b24-8896-250c0a6aa863","order_by":2,"name":"Lizhong Yang","email":"","orcid":"","institution":"University of Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Lizhong","middleName":"","lastName":"Yang","suffix":""},{"id":639045196,"identity":"be5d8cff-c74f-4991-be0f-4df4a6821e98","order_by":3,"name":"Xiaoyu Ju","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYBACxgYgkQBisTdAhQ4QrYXnAFQ1IS0IIJFApBbmGQlsEg9qbBI33Hxj/PlDDYMc340Exs8F+Bw2I4HZIOFYWuKG2zlmEgeOMRhL3khglp6BXwvjgwS2w2AtDAcbGBI33EhgY+bBr4XhQMI/oJabZ4w/ALXUE6OF8UFiG1DLDR4DCaCWBAOCWnoeNhsk9qUZzzyTViZx5piE4cwzD5ul8WkxbE8+Jvnjm41s3/HDmz9U1NjI8x1PPvgZr5YGcGQyODZA+BIM0OjFDeShtD1eVaNgFIyCUTCyAQCNnFLGU1CnjQAAAABJRU5ErkJggg==","orcid":"","institution":"University of Science and Technology of China","correspondingAuthor":true,"prefix":"","firstName":"Xiaoyu","middleName":"","lastName":"Ju","suffix":""}],"badges":[],"createdAt":"2026-04-21 12:53:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9484483/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9484483/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":109342526,"identity":"1335d096-d552-4b1a-be22-f306cef855ed","added_by":"auto","created_at":"2026-05-15 19:24:36","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":761862,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9484483/v1_covered_9d38bc47-03f2-47ee-bc27-d23cd09df29b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Spontaneous ignition of vertically oriented wood exposed to convection and time-dependent thermal radiation: experimental and analytical prediction","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"fire-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"fire","sideBox":"Learn more about [Fire Technology](http://link.springer.com/journal/10694)","snPcode":"10694","submissionUrl":"https://submission.springernature.com/new-submission/10694/3","title":"Fire Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Wood, Ignition behavior, Ignition time prediction, Transient irradiation, Crosswind","lastPublishedDoi":"10.21203/rs.3.rs-9484483/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9484483/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSpontaneous ignition of vertically oriented structural timber induced by transient heat flux and crosswind, which represents a prevalent incident in building fire scenarios, has received little attention in existing studies. This study utilized a self-designed experimental setup, employing five quadratic heat fluxes (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\dot{q}}_{ex}^{{\\prime\\:}{\\prime\\:}}=a{t}^{2}\\)\u003c/span\u003e\u003c/span\u003e, heat flux increasing rates (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:a\\)\u003c/span\u003e\u003c/span\u003e): 0.10, 0.13, 0.18, 0.28, 0.40 W/m\u003csup\u003e2\u003c/sup\u003es\u003csup\u003e2\u003c/sup\u003e) and five crosswind conditions (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{U}_{\\infty\\:}\\)\u003c/span\u003e\u003c/span\u003e= 0, 0.4, 0.8, 1.0, 1.2 m/s) to systematically investigate timber ignition characteristics under coupled transient thermal radiation and convection. Surface temperature, mass loss rate (MLR) and ignition time were measured and analyzed. Analytical solutions for transient surface temperature were derived via one-dimensional heat conduction theory and validated against the experimental data. Using the critical mass loss rate (13 g/m\u003csup\u003e2\u003c/sup\u003es) as the ignition criterion, this study developed ignition time prediction methods applicable to time-dependent thermal radiation scenarios. Results indicate that both surface temperature and MLR are mainly driven by thermal radiation. The approximate solution for the surface temperature is more accurate than the asymptotic solution. An increase in heat flux increasing rate reduces ignition time by an average of 17.4%, while an increase in crosswind speed prolongs ignition time by an average of 3.9%. The theoretical model considering surface heat loss restricts ignition time prediction error to within 20%.\u003c/p\u003e","manuscriptTitle":"Spontaneous ignition of vertically oriented wood exposed to convection and time-dependent thermal radiation: experimental and analytical prediction","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-15 19:23:19","doi":"10.21203/rs.3.rs-9484483/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"244023071221295956556445013382043851945","date":"2026-05-08T14:47:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"184888951708075489135797634004030811891","date":"2026-05-08T05:46:47+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-05-06T14:40:56+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-05-06T12:26:49+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-26T14:07:27+00:00","index":"","fulltext":""},{"type":"submitted","content":"Fire Technology","date":"2026-04-21T12:45:42+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"fire-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"fire","sideBox":"Learn more about [Fire Technology](http://link.springer.com/journal/10694)","snPcode":"10694","submissionUrl":"https://submission.springernature.com/new-submission/10694/3","title":"Fire Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0749a216-cfca-4788-9ac8-61589d0124f6","owner":[],"postedDate":"May 15th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"244023071221295956556445013382043851945","date":"2026-05-08T14:47:58+00:00","index":8,"fulltext":""},{"type":"reviewerAgreed","content":"184888951708075489135797634004030811891","date":"2026-05-08T05:46:47+00:00","index":7,"fulltext":""},{"type":"reviewersInvited","content":"4","date":"2026-05-06T14:40:56+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-05-06T12:26:49+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-15T19:23:20+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-15 19:23:19","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9484483","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9484483","identity":"rs-9484483","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}