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Ong, C. B., Chang, W. S., Ansell, M. P., Brandon, D., Sterley, M. & Walker, P. (2018). Bench-scale fire tests of Dark Red Meranti and Spruce finger joints in tension. Construction and Building Materials, 168, 257-265
Open this publication in new window or tab >>Bench-scale fire tests of Dark Red Meranti and Spruce finger joints in tension
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2018 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 168, p. 257-265Article in journal (Refereed) Published
Abstract [en]

This study investigates the secondary failure of Malaysian Dark Red Meranti (Shorea spp.) and Spruce (Picea abies) finger joints in a glulam beam in a fire test using a bench-scale test set-up. Secondary failure is the occurrence of failure of the bond lines due to fire and the falling off of the outermost tension layers, exposing the uncharred inner layers to a sudden increase of fire intensity. The lack of published work and the difficulties in describing the behaviour of the finger joints after the secondary failure in a full-scale fire test has identified the need for a simple bench-scale method, incorporating the conditions of the standard fire test. This paper focusses on the performance of the finger joints which together with other defects such as knots and splits are generally the weakest component in the glulam beam. The finger joints were bonded with structural adhesives, specifically phenol resorcinol formaldehyde (PRF) and polyurethane (PUR). They were tested in tension to imitate the failure of finger joints on the tension side of a standard fire test of a glulam beam. Constant heat flux was introduced to the finger-jointed specimens to replicate the secondary failure of a glulam beam in the standard fire test. The results of this study indicate a relationship between the charring rate and density of the specimens, with higher density Dark Red Meranti showing lower charring rate compared to the lower density Spruce specimens. Factors such as constant heat flux as opposed to the time-increasing heat flux exposure and specimen size influenced the charring rate of the specimens. The char rate was measured at the early stages of the fire test, which is known to have higher values since the build-up of the charred layers was not sufficiently substantial to protect the inner unburnt wood. Overall, the bench-scale fire test set-up was able to differentiate the fire performance of the adhesives, with PRF showing better fire performance compared to the specimens finger-jointed with PUR adhesive. In addition, tensile tests at ambient temperature showed no significant difference in tensile strength between finger joints bonded with different adhesives for the same wood species. The tensile strengths of the finger joints bonded with different adhesives were influenced by the temperature profile through the joint. The proposed bench-scale fire test was used to compare the quality of the adhesives in a fire situation, specifically with respect to secondary failure. The PRF was selected as the reference adhesive.

Keywords
Bench-scale fire test, Charring rate, Dark Red Meranti (Shoreaspp.), Finger joints, Heat flux, Phenol resorcinol formaldehyde, Polyurethane adhesive, Secondary failure, Spruce (Picea abies), Tensile strength, Adhesives, Fires, Flammability testing, Formaldehyde, Phenols, Plants (botany), Polyurethanes, Tensile testing, Wooden beams and girders, Charring rates, Fire tests, Phenol resorcinol formaldehydes, Picea abies, Polyurethane adhesives
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33426 (URN)10.1016/j.conbuildmat.2018.02.041 (DOI)2-s2.0-85042515822 (Scopus ID)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-03-16Bibliographically approved
Just, A., Brandon, D., Mäger, K. N., Pukk, R., Sjöström, J. & Kahl, F. (2018). CLT compartment fire test. In: WCTE 2018 - World Conference on Timber Engineering: . Paper presented at 2018 World Conference on Timber Engineering, WCTE 2018, 20 August 2018 through 23 August 2018.
Open this publication in new window or tab >>CLT compartment fire test
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2018 (English)In: WCTE 2018 - World Conference on Timber Engineering, 2018Conference paper, Published paper (Refereed)
Abstract [en]

New high-rise timber buildings are planned to be built in the near future all around the world. The fire protection concepts are not always considering natural fire scenarios. As timber is a combustible material, it can contribute to the fire within and outside of the fire compartment. For buildings with cross-laminated timber (CLT) elements the possible fall-off of lamellas should be considered because of the risk for second flashover, which can lead to a continuous fire. However, in case fire service interference or sprinkler activation is absent or inefficient, it may be necessary to design a building so that it leads to a decaying fire. Additionally, it is important to limit fire spread to neighbouring compartments. This paper discusses a compartment test of a two-story building made of CLT performed in Estonia to study delamination behaviour and consequences in compartments with realistic ventilation conditions. State-of-the art solutions to limit fire spread from the first floor into the second floor were applied. This involved robust design of connections, penetrations through the compartment boundary and the façade. The paper provides a description and analysis of the test.

Keywords
Compartment test, Cross laminated timber, Fall-off of lamella, Physically based fire, Fire protection, Floors, Laminating, Timber, Wooden buildings, Combustible materials, Compartment fires, Cross laminated, Fire compartments, Physically based, Protection concepts, Sprinkler activation, Fires
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36680 (URN)2-s2.0-85058162315 (Scopus ID)
Conference
2018 World Conference on Timber Engineering, WCTE 2018, 20 August 2018 through 23 August 2018
Available from: 2018-12-21 Created: 2018-12-21 Last updated: 2019-08-12Bibliographically approved
Brandon, D. (2018). Engineering methods for structural fire design of wood buildings: Structural integrity during a full natural fire. Stockholm
Open this publication in new window or tab >>Engineering methods for structural fire design of wood buildings: Structural integrity during a full natural fire
2018 (English)Report (Other academic)
Place, publisher, year, edition, pages
Stockholm: , 2018. p. 29
Series
RISE Rapport ; 2018:44
Keywords
Timber Structures; CLT; Fire
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:ri:diva-35109 (URN)978-91-88695-83-3 (ISBN)
Funder
Brandforsk, 302-151
Available from: 2018-09-03 Created: 2018-09-03 Last updated: 2018-09-04Bibliographically approved
Brandon, D. & Just, A. (2018). Fire Safety of CLT Buildings with Exposed Wooden Surfaces. In: : . Paper presented at 4th Forum World Building Nordic Växjö.
Open this publication in new window or tab >>Fire Safety of CLT Buildings with Exposed Wooden Surfaces
2018 (English)Conference paper, Published paper (Other academic)
Abstract [en]

An increasing number of tall buildings made of CLT have been built in recent years. Current architectural trends involve having visible timber surfaces in these tall CLT structures. This results in new fire safety challenges, especially because fire service interference is increasingly difficult for increasingly tall buildings.

 

Recently, a number of research projects involving large scale compartment fire testing studied the development of fires in (1) compartments with a fully encapsulated CLT structure and (2) compartments with exposed CLT surfaces. The studies have shown that sufficient gypsum board protection can avoid the involvement of CLT in a fire. However, fall-off of the base layer of gypsum boards during can result in continuous fires that do not extinguish without fire surface interference, as during fall-off large areas of initially protected timber surfaces start to contribute as fuel to the fire.

 

If CLT is exposed to a fire, fire induced delamination of CLT (also lamella fall-off or char fall-off) could occur due to weakening of bond lines within the CLT. During fire induced delamination the exposed lamella falls from the CLT and a new relatively cold timber surface becomes exposed to potentially high temperatures, which effectively makes additional fuel suddenly available to a fire.

 

Very recent studies involved the development of CLT products that are not subject to delamination. The studies indicate that the use of (a) sufficient fire protection, (b) CLT products with thermally resistant adhesives and (c) a limit regarding the surface area of CLT that can be exposed, result in fires that decay and eventually self-extinguish.

This paper reviews the studies and includes a summary of conclusions.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36537 (URN)
Conference
4th Forum World Building Nordic Växjö
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2019-06-27Bibliographically approved
Brandon, D., Just, A. & Östman, B. (2018). Förslag för brandskydd i flervånings trähus.
Open this publication in new window or tab >>Förslag för brandskydd i flervånings trähus
2018 (Swedish)Report (Other academic)
Abstract [sv]

Denna rapport ger förslag på lösningar för brandskydd i höga trähus. De förslag som ges är inte fullständiga och andra åtgärder kan vara aktuella för att få till ett bättre brandskydd i höga trähus. De förslag som presenteras baseras på arbetet i forskningsprojektet

Brandskydd i höga trähus, som finansierats av Brandforsk (Brandforsk projekt 301-152) och Svenskt Trä och denna rapport är till stora delar en översättning av RISE report 2018:43 "Mitigation of fires in multi-storey timber buildings – statistical analysis and guidelines for design" av Daniel Brandon, Alar Just, Petra Andersson och Birgit Östman.

Brandnormer inriktas i första hand på personsäkerhet, men i höga och stora byggnader blir egendomsskyddet allt viktigare. De förslag som ges här baseras främst på analys av stora skador i USA. De viktigaste punkterna är att begränsa

1. Direkt brand- och rökspridning mellan brandceller via:

a. dörrar, väggar och bjälklag

b. anslutningar mellan byggnadselement

c. genomföringar i väggar och bjälklag

d. installationer i väggar och bjälklag

2. Brand- och rökspridning genom hålrum:

a. i brandcellsavskiljande byggnadselement

b. i fasader och yttertak

3. Utvändig brand- och rökspridning:

a. längs fasadens yta

b. genom fönster

c. genom ventilationsöppningar (t ex vid takfot)

d. på vindar

Publisher
p. 32
Series
RISE Rapport ; 2018:46
Keywords
brand, brandstopp, brandspridning, detaljlösningar, egendomsskydd, höga trähus
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38515 (URN)978-91-88695-86-4 (ISBN)
Available from: 2019-04-29 Created: 2019-04-29 Last updated: 2019-06-27Bibliographically approved
Brandon, D., Just, A., Andersson, P. & Östman, B. (2018). Mitigation of fire damages in multi-storey timber buildings: Statistical analysis and guidelines for design.
Open this publication in new window or tab >>Mitigation of fire damages in multi-storey timber buildings: Statistical analysis and guidelines for design
2018 (English)Report (Other academic)
Abstract [en]

The number of multi-storey timber buildings has increased during the last twenty years. Recent well-known fires in London, Dubai and Brazil, although not in timber buildings, have increased concerns regarding large fire spread and high damage fires. As timber is a combustible material, concerns have been expressed regarding property safety and it has been questioned whether fire damage is more significant in buildings with timber as the main structural material than in other types of buildings. This report includes a statistical study of data of fires in multi-storey timber buildings in New Zealand and an analysis of high damage fires that occurred in multi-storey timber buildings in the USA. The data from New Zealand showed no significant difference between share of fires that had flame damage out of the compartment of origin in (a) multi-storey timber buildings that were constructed in or later than 1992 and (b) other types of multi-storey buildings that were constructed in or later than 1992. Fires in multi-storey timber buildings that were constructed before 1992 spread more frequently to neighbouring compartments than fires in other multi-storey timber buildings constructed before 1992. Data of high damage fires occurring in multi-storey timber buildings in the USA indicated that outdoor fire spread is the most common cause for large fire spread. Additionally, the data indicates that high water damage is most often caused by fire service interference and is significantly less often related to sprinkler activation.

Based on the analysis of fire spread of high damage fires in the USA, guidelines are given in the report to limit (1) outdoor fire spread, (2) fire spread through cavities, and (3) fire spread directly from a fire compartment to a neighbouring fire compartment. A number of these guidelines were evaluated using a fire test of a two-storey timber structure.

Publisher
p. 47
Series
RISE Rapport ; 2018:43
Keywords
Tall timber buildings; Fire; Fire stop; Fire spread; Water damage
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:ri:diva-35110 (URN)978-91-88695-82-6 (ISBN)
Available from: 2018-09-03 Created: 2018-09-03 Last updated: 2019-06-27Bibliographically approved
Brandon, D., Kagiya, K. & Hakkarainen, T. (2018). Performance based design for mass timber structures in fire– A Design Example. In: : . Paper presented at Final Conference of COST Action FP1404.
Open this publication in new window or tab >>Performance based design for mass timber structures in fire– A Design Example
2018 (English)Conference paper, Published paper (Other academic)
Abstract [en]

Recent fires in tall buildings occurring in for example London, Dubai, Sao Paulo and Tehran evidence the risk of high consequences of fires in tall buildings and difficulties for fire service interference in case of large fire spread. In order to reduce the risk of deadly and large damage fires in especially tall buildings it is of importance to limit fire spread and avoid collapse .

It was previously indicated that prescriptive fire safety regulations are mostly based on experience rather than on scientific facts. Therefore, the application of regulations for less conventional buildings, such as tall timber buildings, is questionable. In contrast with prescriptive requirements, performance based requirements, such as a requirement for a building to withstand a full fire without effective fire service interference, require accounting for the design and the function of the building. Multiple performance based methods for the fire safety design are available for buildings with conventional structural materials, i.e. steel and concrete. For buildings with timber as a structural material performance based structural design is rarely applied due to lack of methods available.

The number of tall buildings with timber as their main structural material is increasing globally, which involves new fire safety challenges. In contrast with more conventional structural materials for tall buildings, timber can fuel the fire and influence its duration and severity. A number of previous experimental studies have shown that enough contribution of exposed timber to the fuel of a fire can result in continuous fully developed fires. Additionally, events that lead to increased combustion, such as sudden exposure of initially protected timber or bond line failure in glued timber members, can lead to fire regrowth after a period of decay. Without effective sprinkler or fire service interference, these fires would eventually lead to collapse, which can lead to potentially unacceptable consequences in very tall buildings.

Keywords
Natural fire, Compartment fire, Exposed timber, CLT, Performance Based Design
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36540 (URN)
Conference
Final Conference of COST Action FP1404
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2019-01-22Bibliographically approved
Sterley, M., Noren, J., Liblik, J., Brandon, D. & Just, A. (2018). Small-scale test method for the fire behaviour of woodadhesive bonds in CLT. In: Book of abstracts of the final conference COST FP1404”Fire Safe Use of Bio-Based Building Products”: . Paper presented at COST FP 1404 Final Conference.
Open this publication in new window or tab >>Small-scale test method for the fire behaviour of woodadhesive bonds in CLT
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2018 (English)In: Book of abstracts of the final conference COST FP1404”Fire Safe Use of Bio-Based Building Products”, 2018Conference paper, Published paper (Other academic)
Abstract [en]

There is an increasing use of cross laminated timber (CLT) in the building sector. CLT is a wood panel product made from layers of solid lumber boards. Each layer of boards is oriented perpendicular to adjacent layers and glued on the wide faces of each board. It has been recognised that different adhesive systems have different behaviour in fire; especially that delamination behaviour of CLT can be avoided by choosing a suitable adhesive system. The best method for evaluation of the delamination is a full‐scale fire test, but considering the high costs of such tests, it is of the utmost importance to develop small‐scale methods for evaluating the adhesive bond properties in fire. The intention is that such small‐scale methods should provide the same results as full‐scale tests. A new, smaller scale method for classifying adhesives with respect to  fire properties would also simplify  the planning of  full scale  tests. Previous  tested small‐scale method for evaluation of finger joints is presented in (1).  In this study, a small‐scale fire test methodology for evaluation of CLT adhesive bond performance in  fire  is  introduced  (2).  The  aim  was  to  demonstrate  an  easy  tool  to  distinguish  between  fire resistant adhesive bonds and non‐fire‐resistant bonds, especially with respect to delamination. The cone heater of a cone calorimeter was used to carry out the tests. Cone calorimeter in accordance with ISO 5660 is one of the most widely used bench‐scale instrument in fire research. This small‐scale  device  has  several  advantages  over  larger‐scale  tests  thanks  to  its  fast,  simple  and  cost‐efficient manner to investigate basic material properties.  

Keywords
cross laminated timber, adhesives, delamination, fire performance, small‐scale test
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36538 (URN)
Conference
COST FP 1404 Final Conference
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2019-06-27Bibliographically approved
Schmid, J., Brandon, D., Werther, N. & Klippel, M. (2018). Technical note - Thermal exposure of wood in standard fire resistance tests. Fire safety journal
Open this publication in new window or tab >>Technical note - Thermal exposure of wood in standard fire resistance tests
2018 (English)In: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226Article in journal (Refereed) In press
Abstract [en]

Recently, standard fire resistance testing has been questioned for combustible products. A part of the comments address the thermal boundary conditions and the different thermal exposure of combustible products in comparison to incombustibles. These comments are evaluated in this technical note.To compare heat flux measurements of combustibles and incombustible products when tested in a furnace, furnace tests were performed. The furnace was controlled by plate thermometers to follow the EN 1363/ISO 834 standard temperature-time curve. It could be proven that (a) the heat flux measurements at the specimens surface behind the plate thermometer (PT) are not higher than in front of the PT. The reason for this is most likely that no flaming combustion is possible near the surface due to the low oxygen content typically for a furnace. It could be further shown (b) that the heat flux measurements when combustibles are tested follow the trend reported in literature for incombustibles. Further, (c) that the lower burner fuel used in furnaces is due to the contribution of the specimen (ca. 30% in the presented tests) and due to the lower thermal inertia (ca. 20% in the presented tests). Finally it can be concluded that the thermal exposure of combustibles and incombustibles is equivalent in furnaces simulating a ventilation controlled fire development for a pre-defined duration.

Place, publisher, year, edition, pages
Elsevier Ltd, 2018
Keywords
Combustibility, Fire resistance, Furnace testing, Heat flux, Thermal exposure, Wood, Flammability, Furnaces, Heat resistance, Thermometers, Flaming combustion, Heat flux measurement, Low oxygen contents, Plate thermometers, Resistance testing, Temperature-time curves, Thermal boundary conditions
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-39225 (URN)10.1016/j.firesaf.2018.02.002 (DOI)2-s2.0-85042669776 (Scopus ID)
Available from: 2019-06-26 Created: 2019-06-26 Last updated: 2019-06-26Bibliographically approved
Schmid, J., Lange, D., Sjöström, J., Brandon, D., Klippel, M. & Frangi, A. (2018). The use of furnace tests to describe real fires of timber structures. In: WCTE 2018 - World Conference on Timber Engineering: . Paper presented at 2018 World Conference on Timber Engineering, WCTE 2018, 20 August 2018 through 23 August 2018. World Conference on Timber Engineering (WCTE)
Open this publication in new window or tab >>The use of furnace tests to describe real fires of timber structures
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2018 (English)In: WCTE 2018 - World Conference on Timber Engineering, World Conference on Timber Engineering (WCTE) , 2018Conference paper, Published paper (Refereed)
Abstract [en]

Fire resistance is an important characteristic for all building structures regardless the building materials used. Methods for fire resistance testing were developed already before 1900 to measure the response of the structure in fire and compare different products. In the last decade, the increased popularity of timber buildings has led to a renewed interest in the performance of timber structures in fire and timber products were frequently tested in furnaces. Currently, some discussions question the validity of furnace test results for timber members which are carried out according to standards. Generally, it was stated that combustible and incombustible products are exposed to different thermal exposures when tested in furnaces or exposed in real fires. Additionally, some experts think that massive timber elements, e.g. cross-laminated timber (CLT), cannot be tested in furnaces as these products increase the fire load and, thus, statements in the framework of fire resistance testing are not possible. This paper investigates the validity of furnace resistance testing for combustible products and its limitations. It is shown that, firstly, the thermal exposure in fire resistance tests of incombustibles and combustibles is similar. Secondly, in addition to thermal exposure, the term fire exposure should be introduced where the oxygen concentration is described as the oxygen concentration significantly influences the behaviour of combustible material in fires. Thirdly, the furnace and compartment environment in flash-over fires is similar with respect to this fire exposure. Finally, it is not possible to directly use furnace test results to predict a compartment response in real fires including the cooling phase but recent investigations indicate that results from fire resistance tests can be used to predict burn-out when the mass loss of the timber specimen is measured.

Place, publisher, year, edition, pages
World Conference on Timber Engineering (WCTE), 2018
Keywords
Combustibility, Compartment fires, Fire resistance tests, Structures, Timber, Flammability, Furnaces, Oxygen, Structure (composition), Testing, Wooden buildings, Building structure, Combustible materials, Fire resistance test, Furnace resistance, Oxygen concentrations, Resistance testing, Timber structures, Fire resistance
National Category
Civil Engineering
Identifiers
urn:nbn:se:ri:diva-37312 (URN)2-s2.0-85056741746 (Scopus ID)
Conference
2018 World Conference on Timber Engineering, WCTE 2018, 20 August 2018 through 23 August 2018
Available from: 2019-01-18 Created: 2019-01-18 Last updated: 2019-06-27Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7663-1525

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