Skip header and navigation

Refine Results By

330 records – page 1 of 17.

A Circular Approach for the Fire Safety Design in Mass Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue3095
Year of Publication
2022
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Author
Siri, Qvist
Organization
Delft University of Technology
Year of Publication
2022
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Fire
Keywords
Mass Timber
Fire Safety Design
Circular Design
Fire Risk
Fire Resilience
Research Status
Complete
Summary
The building industry consumes a lot of material, which causes depletion of material stocks, toxic emissions, and waste. Circular building design can help to reduce this impact, by moving from a linear to a circular design approach. To reach a circular build environment, all disciplines should be involved, including fire safety design. However, there is a contradiction between the objectives of circular and fire safety design, either affecting the aim of protection of material sources, or protection against fire risk. Timber is a material that has high potential in contributing to a circular building industry, as it is renewable, recyclable and can store CO2. However, timber is combustible, which increases the risk of fire. Therefore, mass timber building design has traditionally been restricted by building regulations. To enhance mass timber building design research on timber buildings has increased, to allow understanding of the risks. However, yet general guidelines or understanding on the fire behaviour and risk in timber buildings is lacking. This is a problem for the fire safety design and the potentials of timber contributing to a circular building industry. Until now, there was no specific method available that quantifies this relation between material use and fire risk in mass timber buildings. This limits the possibility of fire safety design and mass timber design to contribute to a more circular building industry. By creating a method that allows comparison between the economic and environmental impact of material use and fire risk, a well-founded choice of building materials is easier to make. The design tool created in this research quantifies the impact on material use for fire safety measures relating to CLT, encapsulation and sprinkler availability and their effect on the fire risk in mass timber buildings. This way insight is provided between the balance of material use and fire risk. By the sum of the impact on material use and fire risk, the total “circular fire safety impact” value is calculated. This value represents the total economic and environmental impact of the design based on the choice of building materials. By changing the fire safety design, the most optimal design variant can be determined. This is the variant with the lowest total impact value. This way, a circular design approach is used to steer fire safety design in mass timber buildings towards a design solution that does not only provide sufficient safety for people, but also provides maximum economic and environmental safety from a material point of view.
Online Access
Free
Resource Link
Less detail

Thermophysical properties of balsa wood used as core of sandwich composite bridge decks exposed to external fire

https://research.thinkwood.com/en/permalink/catalogue3073
Year of Publication
2022
Topic
Fire
Application
Decking
Author
Vahedi, Niloufar
Tiago, Carlos
Vassilopoulos, Anastasios P.
Correia, João R.
Keller, Thomas
Organization
École Polytechnique Fédérale de Lausanne (EPFL)
Universidade de Lisboa
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Application
Decking
Topic
Fire
Keywords
Balsa Wood
Effective Thermophysical Properties
Thermal Conductivity
Specific Heat Capacity
Coefficient of Thermal Expansion
Charring Temperature
Charring Rate
Research Status
Complete
Series
Construction and Building Materials
Summary
The load-bearing performance of sandwich bridge decks comprising a balsa core and fiber-reinforced polymer composite face sheets exposed to fire is a main concern regarding the application of these deck systems. In order to obtain the thermal responses of the balsa core exposed to fire, the temperature-dependent values of thermal conductivity and specific heat capacity are required. Furthermore, information about the char depth and charring rate and the temperature-dependent coefficient of thermal expansion is also needed for the subsequent thermomechanical modeling. In the current study, the effective thermal conductivity and specific heat capacity of balsa up to 850 °C were obtained from one-dimensional transient heat transfer models and experimental data using an inverse heat transfer analysis. The results showed that both properties depend significantly on the stages of combustion, direction of heat flow (in the tracheid or transverse direction) and density. Moreover, charring temperatures and rates were obtained, again as a function of direction and density. Finally, the coefficient of thermal expansion was measured in the transverse direction during evaporation and pyrolysis.
Online Access
Free
Resource Link
Less detail

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.
Online Access
Free
Resource Link
Less detail

Large-scale compartment fires to develop a self-extinction design framework for mass timber—Part 1: Literature review and methodology

https://research.thinkwood.com/en/permalink/catalogue2911
Year of Publication
2022
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Xu, Hangyu
Pope, Ian
Gupta, Vinny
Cadena, Jaime
Carrascal, Jeronimo
Lange, David
McLaggan, Martyn
Mendez, Julian
Osorio, Andrés
Solarte, Angela
Soriguer, Diana
Torero, Jose
Wiesner, Felix
Zaben, Abdulrahman
Hidalgo, Juan
Organization
The University of Queesland
University of College London
The University of Edinburgh
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Fire
Keywords
Performance-based Design
Compartment Fires
Heat Transfer
Pretection of Wood
Large-scale
Mass Timber
Research Status
Complete
Series
Fire Safety Journal
Summary
Fire safety remains a major challenge for engineered timber buildings. Their combustible nature challenges the design principles of compartmentation and structural integrity beyond burnout, which are inherent to the fire resistance framework. Therefore, self-extinction is critical for the fire-safe design of timber buildings. This paper is the first of a three-part series that seeks to establish the fundamental principles underpinning a design framework for self-extinction of engineered timber. The paper comprises: a literature review introducing the body of work developed at material and compartment scales; and the design of a large-scale testing methodology which isolates the fundamental phenomena to enable the development and validation of the required design framework. Research at the material scale has consolidated engineering principles to quantify self-extinction using external heat flux as a surrogate of the critical mass loss rate, and mass transfer or Damköhler numbers. At the compartment scale, further interdependent, complex phenomena influencing self-extinction occurrence have been demonstrated. Time-dependent phenomena include encapsulation failure, fall-off of charred lamellae and the burning of the movable fuel load, while thermal feedback is time-independent. The design of the testing methodology is described in reference to these fundamental phenomena.
Online Access
Free
Resource Link
Less detail

Smoke Hazards of Tall Timber Buildings with New Products

https://research.thinkwood.com/en/permalink/catalogue2964
Year of Publication
2022
Topic
Fire
Author
Cheng, Chi-Honn
Chow, Cheuk-Lun
Yue, Tsz-Kit
Ng, Yiu-Wah
Chow, Wan-Ki
Organization
City University of Hong Kong
The Hong Kong Polytechnic University
Editor
Formisano, Antonio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Topic
Fire
Keywords
Tall Timber Buildings
Fire Hazards
Smoke Hazards
Public Concerns
New Timber Products
Research Status
Complete
Series
Encyclopedia
Summary
Timber buildings can now stand very tall using new products. As timber materials are expected to be easily ignitable, the fire hazard of timber is a concern. Charring of the timber surface would maintain structural stability, but would also be accompanied by smoke. Although treating timber products with fire retardants would delay the ignition time under low radiative heat flux, toxic combustion products and unburnt fuel would be emitted immediately upon burning. More smoke and higher toxic gas concentrations such as carbon monoxide would be given off upon burning some fire retardants under high flashover heat fluxes. Due to the fast upward movement of smoke under stack effect, spreading of toxic smoke in tall timber buildings would lead to a hazardous environment. Engineered timber consists of derivative timber products. New engineered timber products are manufactured with advanced technology and design, including cross-laminated-timber (CLT), laminated veneer lumber (LVL) and glue-laminated timber (Glulam). The fire behaviour of timber products has been studied for several decades. However, the smoke hazards of using new timber products in building construction should be monitored. The objective of this study is to inspire stakeholders in fire safety of timber buildings, inter alia smoke hazards, to use new timber products to build tall buildings.
Online Access
Free
Resource Link
Less detail

Performance of midply shear wall

https://research.thinkwood.com/en/permalink/catalogue3037
Year of Publication
2022
Topic
Mechanical Properties
Fire
Acoustics and Vibration
Application
Shear Walls
Author
Ni, Chui
Dagenais, Christian
Qian, Cheng
Hu, Lin
Organization
FPInnovations
Year of Publication
2022
Format
Report
Application
Shear Walls
Topic
Mechanical Properties
Fire
Acoustics and Vibration
Keywords
Midply Shear Wall
Structural Performance
Fire Performance
Acoustic Performance
Research Status
Complete
Summary
Midply shear wall, which was originally developed by researchers at Forintek Canada Corp. (predecessor of FPInnovations) and the University of British Columbia, is a high-capacity wood-frame shear wall system that is suitable for high wind and seismic loadings. Its superior seismic performance was demonstrated in a full-scale earthquake simulation test of a 6-storey wood-frame building in Japan (Peietal.,2010). Midply shear wall, however, had limited applications due to its low resistance to vertical load and difficulty to accommodate electrical and plumbing services. For broader applications of Midply shearwall, these limitations needed to be addressed. In collaboration with APA–The Engineered Wood Association and the American Wood Council (AWC), a new framing arrangement was designed to increase the vertical load resistance of Midply shearwalls and make it easier to accommodate electrical and plumbing services. Consequently, structural, fire and acoustic tests have been conducted to evaluate various performance attributes of Midply shear wall with the new framing configuration. This InfoNote provides a summary of the structural, fire and acoustic performance of Midply shearwalls from the tests.
Online Access
Free
Resource Link
Less detail

Fire Performance of Mass Timber

https://research.thinkwood.com/en/permalink/catalogue2824
Year of Publication
2021
Topic
Fire
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
Dagenais, Christian
Ranger, Lindsay
Organization
FPInnovations
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Fire
Keywords
Fire Resistance
CSA 086
National Design Specifications for Wood Construction (NDSR)
Fire Test
Fire Stopping
Connections
Insurance
Mass Timber
Research Status
Complete
Series
InfoNote
Summary
This InfoNote summarizes recent research and work in progress. A significant amount of fire research has been conducted on mass timber over the last 10 years in Canada. This has supported the successful design and construction of numerous low-, mid-and even high-rise wood buildings. This has also fostered the introduction of new provisions into the National Building Code of Canada which has made wood and mass timber construction more accessible. However, the fire performance of these systems remains a concern for many potential occupants or owners of these buildings, not to mention building officials and fire departments. Research at FPInnovations continues to support designers and builders in the use of mass timber assemblies by ensuring fire safe designs.
Online Access
Free
Resource Link
Less detail

Structural Means for Fire-Safe Wooden Façade Design

https://research.thinkwood.com/en/permalink/catalogue2854
Year of Publication
2021
Topic
Fire
Material
Other Materials
Application
Building Envelope
Author
Engel, Thomas
Werther, Norman
Organization
Technical University of Munich
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
Other Materials
Application
Building Envelope
Topic
Fire
Keywords
Fire Safety
Fire Spread
Fire Stop
Wooden Façade
Research Status
Complete
Series
Fire Technology
Summary
This study investigates five fire stop variants used to limit the spread of fire on wooden façades. For this purpose, five fire tests using various types of wooden façade claddings and different fire stops were conducted as full-scale tests and compared to the existing findings. The influences and interactions between the material qualities of the external wall behind the façade cladding, the construction type of the wooden façade cladding, the design of the substructure, the depth of the ventilation gap, and the design of the fire stops were investigated. In evaluating the fire stops, the design of the interior corners, the joint design, and the influence of thermal expansion were examined. Finally, design proposals for the design of fire stops at wooden façades in order to limit the spread of fire were derived based on this evaluation. The outlook presents further needs that need to be investigated in the future in order to clarify undiscussed aspects or points that were ultimately not evaluated within the scope of this study.
Online Access
Free
Resource Link
Less detail

Demonstrating Fire-Resistance Ratings for Mass Timber Elements in Tall Wood Structures

https://research.thinkwood.com/en/permalink/catalogue2919
Year of Publication
2021
Topic
Fire
Material
Solid-sawn Heavy Timber
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Beams
Floors
Author
McLain, Richard
Organization
WoodWorks
Year of Publication
2021
Format
Report
Material
Solid-sawn Heavy Timber
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Beams
Floors
Topic
Fire
Keywords
IBC
Minimum Dimensions
Fire Resistance Rating
Noncombustible Protection
Research Status
Complete
Summary
Changes to the 2021 International Building Code (IBC) have created opportunities for wood buildings that are much larger and taller than prescriptively allowed in past versions of the code. Occupant safety, and the need to ensure fire performance in particular, was a fundamental consideration as the changes were developed and approved. The result is three new construction types—Type IV-A, IV-B and IV-C—which are based on the previous Heavy Timber construction type (renamed Type IV-HT), but with additional fire protection requirements. One of the main ways to demonstrate that a building will meet the required level of passive fire protection, regardless of structural materials, is through hourly fire-resistance ratings (FRRs) of its elements and assemblies. The IBC defines an FRR as the period of time a building element, component or assembly maintains the ability to confine a fire, continues to perform a given structural function, or both, as determined by the tests, or the methods based on tests, prescribed in Section 703. FRRs for the new construction types are similar to those required for Type I construction, which is primarily steel and concrete. They are found in IBC Table 601, which includes FRR requirements for all construction types and building elements; however, other code sections should be checked for overriding provisions (e.g., occupancy separation, shaft enclosures, etc.) that may alter the requirement.
Online Access
Free
Resource Link
Less detail

Experimental analysis of cross-laminated timber rib panels at normal temperature and in fire

https://research.thinkwood.com/en/permalink/catalogue2933
Year of Publication
2021
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Kleinhenz, Miriam
Just, Alar
Frangi, Andrea
Organization
ETH Zurich
Tallinn University of Technology
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Fire
Keywords
Timber Composite Structures
Massive Timber Rib Panel
Fire Resistance
ISO Fire Exposure
Glue Line Quality
Effective Width
Research Status
Complete
Series
Engineering Structures
Summary
The results of an experimental programme on the structural behaviour, fire behaviour, and fire resistance of CLT rib panels are presented. The floor system consists of cross-laminated timber (CLT) plates rigidly bonded to glued-laminated timber ribs by means of screw-press gluing. The experimental programme comprised ultimate-load tests at normal temperature as reference tests and full-scale fire resistance tests on four cross-sections. In addition to the reference tests, shear tests of the glue line between CLT plate and glued-laminated timber rib were performed for analysis of the cross-sections’ composite action. The results of the reference tests show good agreement with results based on the simplified method according to EN 1995-1-1 [1] and its final draft of CLT design [2]. The importance of the glue line’s quality was confirmed. The fire resistance tests show results on the safe side compared to predictions of the fire behaviour according to EN 1995-1-2 [3] and its actual draft [4]. However, the fire resistance was underestimated due to conservative assumptions about the composite cross-section’s structural behaviour. The experimental programme addressed the fire behaviour and fire resistance of CLT rib panels currently not covered in standards. The project’s overall aim is the development of design rules in fire for EN 1995-1-2.
Online Access
Free
Resource Link
Less detail

Advancing Knowledge of Mid-ply Shear Walls: Mid-Ply Shear Wall Fire Resistance Testing

https://research.thinkwood.com/en/permalink/catalogue2808
Year of Publication
2021
Topic
Fire
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Ranger, Lindsay
Dagenais, Christian
Organization
FPInnovations
Year of Publication
2021
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Fire
Keywords
Shear Walls
Fire Resistance Rating
Mid-Rise
Midply Wall
Research Status
Complete
Summary
The objective of this research is to address a knowledge gap related to fire performance of midply shear walls. Testing has already been done to establish the structural performance of these assemblies. To ensure their safe implementation and their broad acceptance, this project will establish fire resistance ratings for midply shear walls. Fire tests will provide information for the development of design considerations for midply shear walls and confirm that they can achieve at least 1-hour fire-resistance ratings that are required for use in mid-rise buildings. This research will support greater adoption of mid-rise residential and non-residential wood-frame construction and improve competition with similar buildings of noncombustible construction. This work will also support the development of the APA system report for midply walls, which will be a design guideline for using midply walls in North America.
Online Access
Free
Resource Link
Less detail

Experimental study of compartment fire development and ejected flame thermal behavior for a large-scale light timber frame construction

https://research.thinkwood.com/en/permalink/catalogue3048
Year of Publication
2021
Topic
Fire
Author
Zhang, Yuchun
Yang, Xiaolong
Luo, Yueyang
Gao, Yunji
Liu, Haiyan
Li, Tao
Organization
Southwest Jiaotong University
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Topic
Fire
Keywords
Light Timber Frame Construction
Room Fire Development
Ejected Flame
Research Status
Complete
Series
Case Studies in Thermal Engineering
Summary
Most of the previous work focused on fire behavior of non-combustible construction. However, few investigations have systematically addressed fire development and window ejected flame based on large-scale light timber frame construction (LTFC). This paper conducted a large-scale natural fire experiment to explore the fire development of wooden buildings and the ejected flame behavior by a two-layer light timber frame construction (LTFC). The experimental LTFC included two compartments, with four façade walls consisted of external and internal linings, within 5.1 m height, 3.6 m long and 2.4 m width, and weight of 1480.1 kg. The room temperature, mass variation in burning, radical temperature profiles outside the openings-façade wall, and ejected flame dimension were measured and analyzed. The results were summarized as follows: In LTFC, the room temperature and heat release rate (HRR) would show a second rapid rise, as if “twice flashover” occurred in fully burning stage. This phenomenon is obviously different from the traditional compartment fire development of buildings. Besides, after flashover, the ejected flame height continuously increased until the fire turned into decay stage, whereas the horizontal ejection distance would maintain a steady stage and increased as the openings broken extremely. Furthermore, the region outside the openings façade wall could be divided into three regions, ejected flame region (including continuous and intermittent flame) (Tr > 180 °C), buoyant plume region(150 °C > Tr > 60 °C) and heated air region(60 °C > Tr > T8). A modified function was proposed to predict the temperature profile at different heights for the openings-ejected flame. The data of this paper will enhance the comprehension for fire development of timber buildings and provide some useful information to assess the thermal behavior of window-ejected flame of façade wall.
Online Access
Free
Resource Link
Less detail

Combination of laser scanner and drilling resistance tests to measure geometry change for structural assessment of timber beams exposed to fire

https://research.thinkwood.com/en/permalink/catalogue3057
Year of Publication
2021
Topic
Fire
Application
Beams
Author
Cabaleiro, Manuel
Suñer, Carlos
Sousa, Hélder S.
Branco, Jorge M.
Organization
University of Vigo
University of Minho
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Application
Beams
Topic
Fire
Keywords
Drilling Resistance Test
Structural Assessment
Laser Scanning
Cloud Point
Research Status
Complete
Series
Journal of Building Engineering
Summary
A structure may be totally destroyed due to a fire, but often it is only partially damaged and parts of it may still be salvaged and reused. For buildings with significant historic and cultural value, it is of utmost importance that these elements, which were only partially damaged, can still be recovered as to preserve the authenticity of the structure. In the case of timber elements after a fire, it is common to find damage on the cross-section exterior part, whereas the inner part presents still a non-damaged section. Therefore, the element is often found with an exterior irregular shape, either due to its original shape prior decay or due to the exposure to fire, that does not coincide with the inner residual cross-section. Moreover, it is essential to perform a preliminary safety analysis to verify which elements can be preserved and to what extent interventions could be needed. The objective of this work is to apply a methodology that allows to calculate the residual cross-section of partially burnt timber elements structures as to calculate the resistant and apparent sections for geometry assessment and to implement that information in three-dimensional structural models. For this purpose, this work proposes a methodology based on a combination of drilling resistance tests together with laser scanner measurements. The methodology was first tested and calibrated within a controlled laboratory environment and then validated onsite using elements from a building exposed to a past fire. The Casa de Sarmento (Sarmento's House) in Guimarães (Portugal) was used as case study, where various structural damages due to a past fire were found.
Online Access
Free
Resource Link
Less detail

Thermal Response of Timber Slabs Exposed to Travelling Fires and Traditional Design Fires

https://research.thinkwood.com/en/permalink/catalogue2935
Year of Publication
2021
Topic
Fire
Application
Wood Building Systems
Author
Richter, Franz
Kotsovinos, Panagiotis
Rackauskaite, Egle
Rein, Guillermo
Organization
Imperial College London
University of California, Berkeley
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Application
Wood Building Systems
Topic
Fire
Keywords
Charring
Travelling Fires
Design Fires
Smouldering
Research Status
Complete
Series
Fire Technology
Summary
Engineered timber is an innovative and sustainable construction material, but its uptake has been hindered by concerns about its performance in fire. Current building regulations measure the fire performance of timber using fire resistance tests. In these tests, the charring rate is measured under a series of heat exposures (design fires) and from this the structural performance is deduced. Charring rates are currently only properly understood for the heat exposure of a standard fire, not for other exposures, which restricts the use of performance-based design. This paper studies the charring rates under a range of design fires. We used a multiscale charring model at the microscale (mg-samples), mesoscale (g-samples), and macroscale (kg-samples) for several wood species exposed to different heating regimes and boundary conditions. At the macroscale, the model blindly predicts in-depth temperatures and char depths during standard and parametric fires with an error between 5% and 22%. Comparing simulations of charring under travelling fires, parametric fires, and the standard fire revealed two findings. Firstly, their charring rates significantly differ, with maximum char depths of 42 mm (travelling), 46 mm (parametric), and 59 mm (standard fire), and one (standard fire) to four (travelling fire) charring stages (no charring, slow growth, fast growth, steady-state). Secondly, we observed zero-strength layers (depth between the 200 °C and 300 °C isotherm) of 7 to 12 mm from the exposed surface in travelling fires compared to 5 to 11 mm in parametric fires, and 7 mm in the standard fire. Both traditional design fires and travelling fires, therefore, need to be considered in structural calculations. These results help engineers to move towards performance-based design by allowing the calculation of charring rates for a wide range of design fires. In turn, this will help engineers to build more sustainable and safe structures with timber.
Online Access
Free
Resource Link
Less detail

Predicting the thickness of zero-strength layer in timber beam exposed to parametric fires

https://research.thinkwood.com/en/permalink/catalogue2916
Year of Publication
2021
Topic
Fire
Application
Beams
Author
Huc, Sabina
Pecenko, Robert
Hozjan, Tomaž
Organization
University of Ljubljana
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Application
Beams
Topic
Fire
Keywords
Charring Depth
Fire Resistance
Hygro-thermal Analysis
Numerical Model
Parametric Fire
Reduced Cross-section Method
Zero-Strength Layer
Research Status
Complete
Series
Engineering Structures
Summary
In the design of timber structures, the mechanical resistance in fire conditions has to be ensured among others. In the European standards, Eurocodes, the reduced cross-section method is given to determine mechanical resistance of timber structural elements in fire conditions. The reduced cross-section method is based on an effective cross-section that is determined by two key parameters, namely the charring depth and the thickness of zero-strength layer where the latter accounts for the reductions of the stiffness and the strength of timber due to elevated temperatures. Although, the thickness of zero-strength layer of 7 mm is only prescribed for the ISO 834 standard fire exposure longer than 20 min in the Eurocodes, the same value is often used for non-standard fire exposures as well, which might not always be correct. Thus, in the present paper the thickness of zero-strength layer is investigated for a timber beam exposed to 44 different parametric fires by means of advanced numerical models and a simple design method. A hygro-thermal model and a mechanical model are applied to determine the temperature field over a timber beam cross-section and the mechanical resistance of the beam during fire exposure, respectively. The simple design method is based on the reduced cross-section method. The obtained results show that the thickness of zero-strength layer varies between 8.4 mm and 30.5 mm, which are substantially higher values than the value of 7 mm suggested in the Eurocodes for the standard fire exposure. The results also indicate that the thickness of zero-strength layer is not a constant value and should be written as a function of the parameters defining a parametric fire curve. Alternatively, the effective cross-section could be simply determined by finding the combined thickness of zero-strength layer and charring depth at temperature of about 90 °C.
Online Access
Free
Resource Link
Less detail

Structural Capacity of One-Way Spanning Large-Scale Cross-Laminated Timber Slabs in Standard and Natural Fires

https://research.thinkwood.com/en/permalink/catalogue2734
Year of Publication
2021
Topic
Fire
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Ceilings
Author
Wiesner, Felix
Bartlett, Alastair
Mohaine, Siyimane
Robert, Fabienne
McNamee, Robert
Mindeguia, Jean-Christophe
Bisby, Luke
Organization
University of Queensland
The University of Edinburgh
CERIB Fire Testing Centre
Brandskyddslaget
University of Bordeaux
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Ceilings
Topic
Fire
Mechanical Properties
Keywords
Deflection
Temperature
Load Bearing Capacity
Ventilation
Fire Safety
Research Status
Complete
Series
Fire Technology
Summary
This paper describes selected observations, measurements, and analysis from a series of large-scale experiments on cross-laminated timber (CLT) slabs that were exposed to fire from below, using four different heating scenarios, with a sustained mechanical loading of 6.3 kN m per metre width of slab. The deflection response and in-depth timber temperatures are used to compare the experimental response against a relatively simple structural fire model to assess the load bearing capacity of CLT elements in fire, including during the decay phase of natural fires. It is demonstrated that the ventilation conditions in experiments with a fixed fuel load are important in achieving burnout of the contents before structural collapse occurs. A mechanics-based structural fire model is shown to provide reasonably accurate predictions of structural failure (or lack thereof) for the experiments presented herein. The results confirm the importance of the ventilation conditions on the fire dynamics, burning duration, and the achievement of functional fire safety objectives (i.e. maintaining stability and compartmentation), in compartments with exposed CLT.
Online Access
Free
Resource Link
Less detail

Fire Performance of Self-Tapping Screws in Tall Mass-Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2877
Year of Publication
2021
Topic
Fire
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Létourneau-Gagnon, Mathieu
Dagenais, Christian
Blanchet, Pierre
Organization
Université Laval
FPInnovations
Editor
Hwang, Cheol-Hong
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Connections
Keywords
Self-Tapping Screws
Heat Transfer
Fire Performance
Finite Element Modeling
Research Status
Complete
Series
Applied Sciences
Summary
Building elements are required to provide sufficient fire resistance based on requirements set forth in the National Building Code of Canada (NBCC). Annex B of the Canadian standard for wood engineering design (CSA O86-19) provides a design methodology to calculate the structural fire-resistance of large cross-section timber elements. However, it lacks at providing design provisions for connections. The objectives of this study are to understand the fire performance of modern mass timber fasteners such as self-tapping screws, namely to evaluate their thermo-mechanical behavior and to predict their structural fire-resistance for standard fire exposure up to two hours, as would be required for tall buildings in Canada. The results present the great fire performance of using self-tapping screws under a long time exposure on connections in mass timber construction. The smaller heated area of the exposed surface has limited thermal conduction along the fastener’s shanks and maintained their temperature profiles relatively low for two hours of exposure. Based on the heat-affected area, the study presents new design principles to determine the residual length of penetration that would provide adequate load-capacity of the fastener under fire conditions. It also allows determining safe fire-resistance values for unprotected fasteners in mass timber construction exposed up to two hours of standard fire exposure.
Online Access
Free
Resource Link
Less detail

Concealed Spaces in Mass Timber and Heavy Timber Structures

https://research.thinkwood.com/en/permalink/catalogue2920
Year of Publication
2021
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Floors
Decking
Walls
Roofs
Author
McLain, Richard
Organization
WoodWorks
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Floors
Decking
Walls
Roofs
Topic
Fire
Keywords
IBC
Concealed Spaces
Dropped Ceiling
Sprinklers
Noncombustible Insulation
Research Status
Complete
Summary
Concealed spaces, such as those created by a dropped ceiling in a floor/ceiling assembly or by a stud wall assembly, have unique requirements in the International Building Code (IBC) to address the potential of fire spread in nonvisible areas of a building. Section 718 of the 2018 IBC includes prescriptive requirements for protection and/or compartmentalization of concealed spaces through the use of draft stopping, fire blocking, sprinklers and other means.
Online Access
Free
Resource Link
Less detail

Enhancing Thermal and Mechanical Performance of Engineered Wood Product Adhesives using Novel Fire Retardant Nanoclays

https://research.thinkwood.com/en/permalink/catalogue2810
Year of Publication
2021
Topic
Mechanical Properties
Fire
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Oguzlu-Baldelli, Hale
Yu, Jason
Lee, George
Lam, Frank
Jiang, Feng
Organization
University of British Columbia
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Mechanical Properties
Fire
Keywords
Adhesive
PUR
Bond Strength
Halloysite
pMDI
Douglas-Fir
SPF
Bonding Shear Strength
Research Status
Complete
Summary
One component PUR adhesive is widely used in engineered wood products applications, such as cross-laminated timber (CLT). However, the dramatic deterioration of PUR adhesive bond strength at elevated temperature can out tremendously threat for tall wood building, especially under fire. In this project, we are aiming to improving the bond strength of the PUR adhesive at high temperature by incorporating chemically modified halloysite to improve the poor interface between inorganic fillers and the polymer matrices. To improve the interaction with PUR (Loctite UR20 by Henkel®), the halloysite was chemically grafted with polymeric diphenylmethane diisocyanate (pMDI) (pMDI-H). The effect of adding pMDI modified halloysite to the PUR adhesives was investigated in terms of nanofiller dispersibility, thermal and mechanical properties of the pMDI-halloysite-PUR composite film, and the bonding shear strength of the glued Douglas fir and Spruce-Pine-Fir (SPF) shear blocks under different temperature. Significant improvement of the bond shear strength can be observed with the addition of 5 and 10% of pMDI-modified PUR adhesive, and the key research findings are summarized as below, a. pMDI can be successfully grafted onto hydroxylated halloysites to improve its dispersibility in one-component PUR adhesive; b. Addition of pMDI-H into PUR adhesive can lead to improved glass transition temperature and storage modulus. In contrast, no significant enhancement was observed in h-H added PUR films due to the poor dispersibility; c. Addition of up to 10% h-H and pMDI-H did not show significant change of the shear strength at 20 °C for both Douglas Fir and SPF; d. Significant enhancement of shear strength at elevated temperature (60-100 °C) can be observed for 5% and 10% pMDI-H modified PUR adhesive, showing 17% improvement for Douglas Fir and 27-37% for SPF.
Online Access
Free
Resource Link
Less detail

Three-Dimensional Numerical Calculation Model for Static Behavior Simulation of Cross-Laminated Timber Plates under Thermal Environment

https://research.thinkwood.com/en/permalink/catalogue2766
Year of Publication
2021
Topic
Fire
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Hu, Wenliang
Hou, Wei
Zhu, Zhao
Huang, Xuhui
Publisher
Hindawi Publishing Corporation
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Fire
Mechanical Properties
Keywords
Finite Element Method (FEM)
Thermal Behaviour
Thermal Environment
Deformation
Load Bearing Capacity
Research Status
Complete
Series
Mathematical Problems in Engineering
Summary
Cross-laminated timber (CLT) is well known as an interesting technical and economical product for modern wood structures. The use of CLT for modern construction industry has become increasingly popular in particular for residential timber buildings. Analyzing the CLT behavior in high thermal environment has attracted scholars’ attention. Thermal environment greatly influences the CLT properties and load bearing capacity of CLT, and the investigation can form the basis for predicting the structural response of such CLT-based structures. In the present work, the finite element method (FEM) is employed to analyze the thermal influence on the deformation of CLT. Furthermore, several factors were taken into consideration, including board layer number, hole conformation, and hole position, respectively. In order to determine the influence, several numerical models for different calculation were established. The calculation process was validated by comparing with published data. The performance is quantified by demonstrating the temperature distribution and structural deformation.
Online Access
Free
Resource Link
Less detail

330 records – page 1 of 17.