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7 records – page 1 of 1.

Auto-Extinction of Engineered Timber as a Design Methodology

https://research.thinkwood.com/en/permalink/catalogue1676
Year of Publication
2016
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Author
Bartlett, Alastair
Hadden, Rory
Bisby, Luke
Lane, Barbara
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Fire
Keywords
Extinction
Fire Propagation Apparatus
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3934-3941
Summary
Engineered timber products such as cross-laminated timber (CLT) are gaining popularity with designers due to attractive aesthetic, sustainability, and constructability credentials. The fire behaviour of such materials is a key requirement for buildings formed predominantly of exposed, structural timber elements. Whilst design guidance focuses on the residual structural capacity of timber elements exposed to a ‘standard fire’, the fundamental characteristics of CLT’s performance in fire, such as ignition, flame spread, delamination, and extinction are not currently considered. This paper focuses on the issues relating to increased fuel load due to a combustible building material itself. Whilst an increasingly common protection solution to this conundrum is to fully encapsulate the timber elements, there is limited supporting test data on this approach. Through understanding these concepts from a fundamental, scientific perspective, the behaviour can be properly understood, and, rather than limiting design, can be incorporated into design to satisfy suitable performance criteria. In this paper therefore, the concept of auto-extinction – a phenomenon by which a timber sample will cease flaming when the net heat flux to the sample drops below a critical value – is explored experimentally and related to firepoint theory. A series of c.100 small scale tests in a Fire Propagation Apparatus (FPA) have been carried out to quantify the conditions under which flaming extinction occurs. Critical mass loss rate at extinction is shown to occur at a mass flux of 3.5g/m2s or a temperature gradient of 28K/mm at the charline. External heat flux and airflow were not found to affect the critical mass loss rate at the range tested. This approach is then compared with a compartment fire with multiple exposed timber surfaces. With further testing and refinement, this method may be applied in design, enabling architects’ visions of exposed, structural timber to be safely realised.
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Description of Small and Large-Scale Cross Laminated Timber Fire Tests

https://research.thinkwood.com/en/permalink/catalogue1339
Year of Publication
2017
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Rooms
Wood Building Systems
Author
Emberley, Richard
Putynska, Carmen
Bolanos, Aaron
Lucherini, Andrea
Solarte, Angela
Soriguer, Diana
Gonzalez, Mateo
Humphreys, Kathryn
Hidalgo, Juan
Maluk, Cristian
Law, Angus
Torero, Jose
Publisher
ScienceDirect
Year of Publication
2017
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Rooms
Wood Building Systems
Topic
Fire
Keywords
Large Scale
Small Scale
Compartment Fire Test
Heat Flux
Temperature
Self-Extinction
Research Status
Complete
Series
Fire Safety Journal
Summary
A large-scale fire test was conducted on a compartment constructed from cross laminated timber (CLT). The internal faces of the compartment were lined with non-combustible board, with the exception of one wall and the ceiling where the CLT was exposed directly to the fire inside the compartment. Extinction of the fire occurred without intervention. During the fire test, measurements were made of incident radiant heat flux, gas phase temperature, and in-depth temperature in the CLT. In addition, gas flow velocities and gas phase temperatures at the opening were measured, as well as incident heat fluxes at the facade due to flames and the plume leaving the opening. The fuel load was chosen to be sufficient to attain flashover, to achieve steadystate burning conditions of the exposed CLT, but to minimize the probability of uncertain behaviors induced by the specific characteristics of the CLT. Ventilation conditions were chosen to approximate maximum temperatures within a compartment. Wood cribs were used as fuel and, following decay of the cribs, selfextinction of the exposed CLT rapidly occurred. In parallel with the large-scale test, a small scale study focusing on CLT self-extinction was conducted. This study was used: to establish the range of incident heat fluxes for which self-extinction of the CLT can occur; the duration of exposure after which steady-state burning occurred; and the duration of exposure at which debonding of the CLT could occur. The large-scale test is described, and the results from both the small and large-scale tests are compared. It is found that selfextinction occurred in the large-scale compartment within the range of critical heat fluxes obtained from the small scale tests.
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Effects of Exposed Cross Laminated Timber on Compartment Fire Dynamics

https://research.thinkwood.com/en/permalink/catalogue1340
Year of Publication
2017
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Rooms
Author
Hadden, Rory
Bartlett, Alastair
Hidalgo, Juan
Santamaria, Simón
Wiesner, Felix
Bisby, Luke
Deeny, Susan
Lane, Barbara
Publisher
ScienceDirect
Year of Publication
2017
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Rooms
Topic
Fire
Keywords
Compartment Fires
Heat Release Rate
Temperature
Exposed Timber
Auto-Extinction
Combustible Material
Heat Transfer
Research Status
Complete
Series
Fire Safety Journal
Summary
A series of compartment fire experiments has been undertaken to evaluate the impact of combustible cross laminated timber linings on the compartment fire behaviour. Compartment heat release rates and temperatures are reported for three configuration of exposed timber surfaces. Auto-extinction of the compartment was observed in one case but this was not observed when the experiment was repeated under identical condition. This highlights the strong interaction between the exposed combustible material and the resulting fire dynamics. For large areas of exposed timber linings heat transfer within the compartment dominates and prevents auto-extinction. A framework is presented based on the relative durations of the thermal penetration time of a timber layer and compartment fire duration to account for the observed differences in fire dynamics. This analysis shows that fall-off of the charred timber layers is a key contributor to whether auto-extinction can be achieved.
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Effects of Fuel Load and Exposed CLT Surface Configuration in Reduced-Scale Experiments

https://research.thinkwood.com/en/permalink/catalogue2047
Year of Publication
2018
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Bateman, Christopher
Bartlett, Alastair
Rutkauskas, Lukas
Hadden, Rory
Organization
The University of Edinburgh
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Fire
Keywords
Auto-Extinction
Fuel Load
Delamination
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
With increasing regularity, compartments with exposed timber boundaries are being proposed in high-rise buildings. However, due to the combustible nature of timber, the fire-specific risks associated with these decisions must be thoroughly explored. In particular the requirement that the timber stops burning after the imposed fuel load has been consumed must be fulfilled. By means of reduced scale experiments it was determined that sustained burning was dependent on both the configuration of exposed faces and, to a lesser extent, the imposed fuel load. The principal factor for auto-extinction or otherwise was found to be in the configuration of exposed surfaces, with two exposed walls (in this case back and side wall) consistently resulting in sustained burning. When a wall and the ceiling were left exposed (wall opposite the compartment opening and ceiling), auto-extinction occurred for all but the highest fuel load considered. The occurrence of char fall-off (delamination) was significant in promoting sustained burning and was observed to cause a transition from apparent extinction back to flaming in one experiment.
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Fundamentals for the Fire Design of Cross Laminated Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2310
Year of Publication
2017
Topic
Fire
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems

Large-Scale Enclosure Fire Experiments Adopting CLT Slabs with Different Types of Polyurethane Adhesives: Genesis and Preliminary Findings

https://research.thinkwood.com/en/permalink/catalogue2963
Year of Publication
2022
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Hopkin, Danny
Wegrzynski, Wojciech
Spearpoint, Michael
Fu, Ian
Krenn, Harald
Sleik, Tim
Gorska, Carmen
Stapf, Gordian
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Fire
Keywords
Adhesive
Bond-line Failure
Char Fall-off
Polyurethane
Auto-Extinction
Flame Spread
Research Status
Complete
Series
Fire
Summary
This paper provides understanding of the fire performance of exposed cross-laminated-timber (CLT) in large enclosures. An office-type configuration has been represented by a 3.75 by 7.6 by 2.4 m high enclosure constructed of non-combustible blockwork walls, with a large opening on one long face. Three experiments are described in which propane-fuelled burners created a line fire that impinged on different ceiling types. The first experiment had a non-combustible ceiling lining in which the burners were set to provide flames that extended approximately halfway along the underside of the ceiling. Two further experiments used exposed 160 mm thick (40-20-40-20-40 mm) loaded CLT panels with a standard polyurethane adhesive between lamella in one experiment and a modified polyurethane adhesive in the other. Measurements included radiative heat flux to the ceiling and the floor, temperatures within the depth of the CLT and the mass loss of the panels. Results show the initial peak rate of heat release with the exposed CLT was up to three times greater when compared with the non-combustible lining. As char formed, this stabilised at approximately one and a half times that of the non-combustible lining. Premature char fall-off (due to bond-line failure) was observed close to the burners in the CLT using standard polyurethane adhesive. However, both exposed CLT ceiling experiments underwent auto-extinction of flaming combustion once the burners were switched off.
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7 records – page 1 of 1.