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Building codes around the globe dictate the design and construction of buildings. For most buildings, designers will follow prescriptive code provisions to demonstrate code compliance. However, some buidling codes allow the use of performance-based design to demonstrate code compliance. Performance-based design is usually more complex but allows for greater flexibility in the use of materials and systems. Regardless of the code compliance methods, the combustibility of timber structures and wood products needs to be well understood and properly accounted for in building designs. This paper describes the develpment of a new international guidance document on fire safety in timber building within the Fire Safe Use of Wood (FSUW) network, written by 13 lead authors assisted by more than 20 experts in over a dozen different countries.

This chapter covers control of workmanship, fire safety during construction, responsibilities and enforcement, fire detection and suppression and emergency procedures. Quality and inspection of workmanship are vital for high-quality buildings, whether of timber or other construction materials. Timber buildings require certain precautions due to the risk for greater exposure of combustible materials. Furthermore, not all fire safety measures for the final building will be in place throughout construction; consequently, adequate processes are required to maintain the fire safety of building sites. All construction sites require formalised fire safety management systems, including auditing of contractors and subcontractors.

This chapter summarises the regulatory control systems for fire safety design of buildings in different regions around the globe. It is focused on the possibilities to use wood products and timber structures according to prescriptive requirements. The possible use of structural timber elements and visible wood surfaces in interior and exterior applications are reviewed and presented in tables and maps. They apply mainly to residential and office buildings. Performance-based requirements may be used in several countries and can be used to verify further applications of wood.

A wide variety of active fire protection systems are available to fire safety practitioners. In addition to passive fire protection measures, some level of active fire protection is normally required to meet the expected minimum level of fire safety in modern buildings. Active fire protection can also be used to increase the fire safety in order to achieve a more flexible fire safety design and an acceptable level of fire safety in buildings. There are many types of active fire protection systems, but this chapter deals mainly with automatic fire sprinkler systems, since they are often used to facilitate the use of timber as structure, internal linings and external facades in large or complex buildings. Sprinklers are required in some countries for taller timber buildings, as described in Chapter 4.

This chapter describes means of preventing spread of fire and smoke between compartments in timber buildings. Much of this applies to all buildings independent of materials used, but some topics are especially relevant for timber buildings. This chapter highlights critical paths of possible spread of fire into, within and through timber structures, including solutions and detailing to prevent uncontrolled spread of fire and smoke.

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The area under the examination in this thesis is the behaviour of wood in exposure to high temperatures, before charring. The main focus is temperature’s effects on tensile strength. This is first done by examining relevant literature and studies, after which the design aspects are analyzed. Next part of the thesis are the tensile strength experiments conducted in high temperatures. The testing method used in this thesis was steady-state test, where the temperature of the sample is kept constant, and the tension is increased until yielding. Samples were manufactured out of spruce. Based on the connection between temperature and tensile strength presented throughout this thesis, an example of a practical application is derived through a small software built for the purpose of this work. This software can be used as a tool in analysing the results of a fire simulation. The main objective of this thesis was to gather knowledge on the effects of the temperature on tensile strength, and evaluate the adequacy of different design approaches on the fire behaviour of wood, explained in the Eurocode 5. This analysis and complementation of the underlying patterns of the fire design of timber was mainly achieved via tensile tests in elevated temperatures. The results of these tensile strength experiments showed that the correlation between temperature and tensile strength presented in the Eurocode can be used as a good approximation in design applications., Tarkastelun kohteena tässä diplomityössä on puun käyttäytyminen altistettuna korkeille lämpötiloille, ennen hiiltymistä. Pääpainona toimii lämpötilan vaikutus vetolujuuteen. Kyseinen tarkastelu suoritetaan ensin kirjallisuuskatsauksen muodossa, jonka jälkeen suunnitteluprosessiin sisältyvät asiat ovat tarkemman analysoinnin kohteena. Diplomityön seuraavassa osassa suoritetaan puun vetokokeet korkealle lämpötilalle altistettuna. Koemenetelmänä käytettiin vakiolämpötilassa suoritettavaa koetta, jossa kappaleeseen kohdistuvaa jännitystä kasvatettiin kappaleen murtumiseen asti. Kokeissa käytetyt näytteet valmistettiin kuusesta. Tässä työssä esiteltyyn lämpötilan ja vetolujuuden väliseen yhteyteen perustuen luotiin käytännön sovelluksena pieni ohjelmisto, jota voidaan käyttää apuna palosimulointitulosten analysointiin. Tämän diplomityön päätavoitteena oli kerätä tietoa lämpötilan vaikutuksesta puun vetolujuuteen, sekä arvioida Eurokoodi 5:ssä esiteltyjen suunnitteluperiaatteiden pätevyyttä. Tämä puun palomitoituksen taustalla olevien mallien analysointi sekä täydentäminen saavutettiin pääosin vetokokeilla korotetuissa lämpötiloissa. Näiden vetokokeiden tulosten perusteella voidaan sanoa Eurokoodissa esitellyn lämpötilan ja vetolujuuden yhteyden olevan hyvä approksimaatio suunnittelutarkoituksiin.

The use of wooden facade claddings and bio-based insulation materials in external walls are increasing because of esthetical and sustainability reasons. The introduction of performance-based building codes has generally facilitated the wider use of these materials and products in multi-storey buildings, but the use of visible woodas exterior facade claddings is still limited. Key initiating events of facade fires are a) interior fire spreading to external wall system via external openings,b) exterior fire directly adjacent external wall system igniting the wall due to radiant heat and/or flame impingement,and c) exterior fire spatially separated from external wall system resulting from radiant heat. Contribution of bio-based façade claddings and insulation materials to fire development and spread can beprevented by using protective methods. Examples of these are protection of insulation products by coverings or layers made of materials with good reaction to fire performance and/or with a sufficient protection capacity and/or prevention of facade cladding fires by hindering flames from a flashover room fire by using fire rated windows, automatic window shutters or sprinklers. Fire stops in ventilation cavities or in order to interrupt acombustible insulation are also effective means of fire protection. Several wooden facade systems do fulfil at least the European reaction to fire class D-s2, d0. Based on fullscale test results some conclusions and recommendations have been made concerning proper criteria and possible area limits of wooden facades. Fire retardant treated wood may be used, but the durability of the fire retardant treatments at exterior weather conditions need to be demonstrated in addition to the fire behaviour. The new European standard EN 16755for testing and classification of fire retardant treated timber products durability is suitable for this purpose. This Guidance document on fire safety of bio-based facades is the result of work within several

This thesis examines the ability of fire simulator program called Fire Dynamics Simulator (FDS) to model heat transfer between hot surfaces and liquid droplets. This heat transfer is modelled in FDS with a fixed heat transfer coefficient value. In this work a more advanced equation for the heat transfer coefficient is introduced in the heat transfer model, which takes better account of phenomena occurring in droplets. The operation of heat transfer models has been evaluated by simulating the three experimental conditions obtained from the literature on both heat transfer models. Two tests are micro scale experiments in which a heated metal plate has been cooled by a water jet. The scale of these trials is a few centimetres. The third test is a large-scale experiment in which the cooling effect of sprinklers has been studied to surface temperatures of steel truss in a room fire. When comparing the results of the simulations with the experimental results, it is noticed that neither of two heat transfer models are able to predict the surface cooling in the microscale experiments very precisely. This is likely to be due to the fact that no all factors affecting heat transfer have been observed such as varying speeds of the droplets on the surfaces or the effect of the boiling on the heat transfer coefficient. Also, the suitability of the equations used for the heat transfer of the improved model to droplets is questionable. In a room fire where the surfaces were cooled by sprinklers, the differences between simulated and measured temperatures were minimal. On a large scale, the sprinkler’s cooling effect to hot rises to a significant degree and also the surface temperatures drop rapidly to a level where the modelling of heat transfer between the surface and droplets does not have to be very accurate. Based on the results, it can be stated that FDS is well suited for the simulation of surface temperatures in sprinkled room fires using either of the heat transfer, Tässä diplomityössä tarkastellaan palosimulointiohjelmisto Fire Dynamics Simulatorin (FDS) kykyä mallintaa lämmönsiirtymistä kuumien pintojen ja nestepisaroiden välillä. Tätä lämmönsiirtymistä on FDS:ssä mallinnettu kiinteällä lämmönsiirtymiskertoimen arvolla. Tässä työssä esitetään lämmönsiirtoalimalliin lämmönsiirtokertoimelle kehittyneempi yhtälö, joka ottaa paremmin huomioon pisaroissa tapahtuvia ilmiöitä. Lämmönsiirtymismallien toimintaa on arvioitu simuloimalla kirjallisuudesta saatuja kolmea kokeellista tilannetta molemmilla lämmönsiirtomalleilla. Kaksi koetta ovat pienoisskaalan kokeita, joissa kuumennettua metallilevyä on jäähdytetty vesisuihkulla. Näiden kokeiden mittakaava on muutamia senttejä. Kolmas koe on suuren skaalan koe, jossa on tutkittu sprinklerien jäähdytysvaikutusta teräsristikkoon huoneistopalossa. Kun simulointien tuloksia verrataan kokeellisiin tuloksiin, huomataan, etteivät kummatkaan lämmönjohtumismallit kykene ennustamaan pinnan jäähtymistä pienen skaalan kokeissa kovinkaan tarkasti. Tämä johtuu todennäköisesti siitä, ettei malleissa ole huomioitu lämmönsiirtymiseen vaikuttavia tekijöitä kuten pisaroitten vaihtelevaa nopeutta pinnoilla tai kiehumisen vaikutusta lämmönsiirtokertoimeen. Myöskään parannellun mallin lämmönsiirtymiseen käytettyjen yhtälöiden soveltuvuus pisaroihin on kyseenalaista. Huonepalossa, jossa pintoja jäähdytetään sprinklauksella, simuloitujen ja mitattujen lämpötilojen ero oli vähäinen. suuressa mittakaavassa sprinklauksen vaikutus kaasujen lämpötilaan nousee merkittävään asemaan samalla kun pintojen lämpötilat putoavat nopeasti tasolle, jossa lämmönsiirtymisen mallintaminen pinnan ja pisaroiden välillä ei tarvitse olla kovin tarkkaa. Tulosten pohjalta voidaan todeta, että FDS soveltuu hyvin pintalämpötilojen simulointiin sprinklatuissa huonepaloissa käytettiinpä kumpaa tahansa lämmönsiirtymismallia, mutta kokeellisempiin tilanteisiin malleja tulee kehittää.