Sammanfattning I detta arbete redovisas resultatet från experimentella studier utförda i en konkalorimeter. Materialet som har undersökts består av sammanpressade fanerskivor av bokträ som har pressats under konstant tid och tryck, medan temperaturen varierats. Fanerskikten har då visat sig bindas samman utan några som helst tillsatser. Tekniken för framställandet av skivorna har utvecklats av Carmen Cristescu vid avdelningen för Träteknik på Luleå tekniska universitet. Genom att variera temperaturen uppvisar de färdiga skivorna olika egenskaper, som exempelvis högre sammanbindande förmåga när temperaturen höjs till 250°C. Syftet med detta arbete är att undersöka dessa fanerskivors termiska egenskaper som huvudsakligen består av tid till antändning och avgiven värmeeffekt. Antändningstiden har även jämförts med handberäkningar. Data från experimentet har sedan jämförts med data från andra studier för liknande produkter som exempelvis plywood och LVL skivor (fanerlaminatträ), som innehåller bindemedel i form av lim.   Resultatet i denna studie tyder på mindre inbördes skillnader mellan fanerskivorna som pressats under olika temperaturer. Studien visar inte heller några större skillnader mot de andra jämförda trämaterialen. Okulära iakttagelser under experimentet indikerar dock skillnader för de sammanbindande egenskaperna när fanerskivorna utsätts för hög temperatur i experimentet. Då fanerskivorna i studien uppvisar likvärdig värmeutveckling som exempelvis plywood så är det rimligt att anta att samma användningsområde kan rekommenderas. I rapporten kommer skivorna för enkelhetens skull att benämnas låg, medium och hög densitet. Detta eftersom de olika pressningstemperaturerna (200, 225 och 250°C) som använts vid framställningen, gav skivorna olika densitet med medelvärden på 745, 823 och 1045 kg/m3. / Abstract This study describes an attempt to determine and evaluate the thermal properties of self-bonding beech veneer. These properties mainly consist of time to ignition and rate of heat release. The determination was done by performing bench-scale trials in a cone calorimeter. The material studied consists of three different sets of self-bonding veneer boards, which have bonded without any additives. The technology for making the boards is developed by Carmen Cristescu. Making the boards involves constant compression under a constant period of time, while allowing a variation in temperature. This results in different characteristics of the final product, such as higher adhesion capabilities between the veneer layers, when the temperature is raised to 250°C. Time to ignition have been measured and compared with hand calculations. All collected data from the experiment and the hand calculations have also been compared to related products, such as plywood and LVL. The study indicates minor differences between the mutual beech veneers, or for example ordinary plywood, regarding the studied characteristics. Observations during the tests indicate that the interconnecting properties vary between the boards when they are subjected to higher temperature. As the study show similar rate of heat release such as plywood, it is reasonable to assume that the same application range can be recommended. Due to the different density 745, 823 and 1045 kg/m3 developed while making the boards and for the further simplicity of the report the boards are henceforth called low, medium and high density boards.

This study describes an approach to determine the thermal conductivity of wood at elevated temperatures. The aim is to be able to use the developed conductivity as input in structural elements in finite element calculations. The conductivity of pine wood and glue laminated timber with different densities and moisture contents have been evaluated where small scale one-dimensional laboratory trials have been carried out in a cone calorimeter. Steel temperatures were measured behind the exposed wood samples. Obtained temperatures from the experimental trials have been compared with back calculated steel temperatures in the finite element program TASEF (Temperature Analysis in Structures Exposed to Fire). In the back calculations the conductivity at 100 °C, 300 °C and 500 °C was altered in order to achieve a best fit steel temperature curve as the measured ones during the experimental trials. At 20 °C the conductivity was taken from the literature. Between these temperature levels the conductivity was assumed to vary linearly. The dehydration of the moisture content in the wood samples have been considered by including it in the specific volumetric enthalpy, i.e. the integral over temperature of the density and specific heat as input in the temperature calculation program TASEF. Regarding the thermal degradation, recommended formulas in Eurocode 5: Design of timber structures – Part 1-2: General – Structural fire design, have been applied. The final back calculated conductivity values of the studied pine wood at specific temperatures (20 °C, 100 °C, 300 °C och 500 °C) were determined by the cone calorimeter test to be as follows; 0.09 W/mK, 0.07 W/mK, 0.05 W/mK and 0.35 W/mK. Comparing with presented conductivity of wood in Eurocode 5 the developed conductivity in this study are generally lower. Derived conductivity values from the back calculations in TASEF have been reconsidered for the glue laminated timber by taken account of differences in density and moisture content. By using a developed conversion factor, so called “conductivity ratio”, new conductivity values could be obtained which then has been used as an input in TASEF. As a result, good similarities between calculated steel temperatures and measured steel temperatures could be seen. The implemented method, consisting of simple one-dimensional laboratory trials for determining the thermal conductivity is deemed to be promising.  However, further studies are needed to be done in order to increase the accuracy of the method.