{"title":"Observations and impact of char layer formation and loss for engineered timber","authors":"Laura Schmidt , Rory M. Hadden , Dilum Fernando","doi":"10.1016/j.firesaf.2024.104196","DOIUrl":null,"url":null,"abstract":"<div><p>The char layer plays a critical role in the fire behaviour of engineered timber. Several chemical and physical processes can reduce char layer thickness and integrity. A series of experiments studied 12 cross-laminated timber (CLT) columns (130 × 790 × 125 mm WxHxD) exposed to combined thermal (20 kW/m<sup>2</sup> or 50 kW/m<sup>2</sup>) and mechanical loading (39 kN, eccentric). Char loss from the surface lamella was observed and the impact of this on the thermal response of the timber studied. In all cases, unprotected CLT exhibited fall-off of charred pieces. Cracking, shrinkage and movement of char contributed significantly to the exposure of underlying timber sections to external heating. There was no direct correlation between char fall-off and the measured glue line temperature in this configuration. To enable comparison between CLT with and without char fall-off, a thin layer of glass fibre-reinforced polymer was added to the exposed surface of six samples which prevented all char fall-off. Retention of the char layer significantly decreased temperatures beneath the char layer, loss of section and burning duration compared to samples with char fall-off.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"147 ","pages":"Article 104196"},"PeriodicalIF":3.4000,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0379711224001097/pdfft?md5=7c573cfadd13df493aa686555f4ab349&pid=1-s2.0-S0379711224001097-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Fire Safety Journal","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0379711224001097","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}
引用次数: 0
Abstract
The char layer plays a critical role in the fire behaviour of engineered timber. Several chemical and physical processes can reduce char layer thickness and integrity. A series of experiments studied 12 cross-laminated timber (CLT) columns (130 × 790 × 125 mm WxHxD) exposed to combined thermal (20 kW/m2 or 50 kW/m2) and mechanical loading (39 kN, eccentric). Char loss from the surface lamella was observed and the impact of this on the thermal response of the timber studied. In all cases, unprotected CLT exhibited fall-off of charred pieces. Cracking, shrinkage and movement of char contributed significantly to the exposure of underlying timber sections to external heating. There was no direct correlation between char fall-off and the measured glue line temperature in this configuration. To enable comparison between CLT with and without char fall-off, a thin layer of glass fibre-reinforced polymer was added to the exposed surface of six samples which prevented all char fall-off. Retention of the char layer significantly decreased temperatures beneath the char layer, loss of section and burning duration compared to samples with char fall-off.
期刊介绍:
Fire Safety Journal is the leading publication dealing with all aspects of fire safety engineering. Its scope is purposefully wide, as it is deemed important to encourage papers from all sources within this multidisciplinary subject, thus providing a forum for its further development as a distinct engineering discipline. This is an essential step towards gaining a status equal to that enjoyed by the other engineering disciplines.