COST Action FP 1303 “Performance of bio-based building materials” successfully started in October 2013 and an ambitious program was set up for the four year programme. COST Actions provide an excellent opportunity for collaborative research, e.g. in the frame of Round Robin tests.

The idea of this respective test was to distribute a fairly simple test set up to as many places in Europe as possible in order to collect performance data reflecting the range of climatic exposure conditions. Furthermore we wanted to consider performance in its manifold meaning, i.e. optical, aesthetical, moisture and functional performance and durability. In contrast to traditional Round Robin tests aiming on comparative evaluation and validation of results from different test laboratories, this initiative aims on collecting performance data under climatically different exposure conditions. Therefore it was required to provide weather data from the respective test sites to allow establishing relationships between climate conditions and the following measured, which shall be evaluated regularly: decay, discolouration, development of mould and other staining fungi, corrosion, formation of cracks and moisture performance (if data logging device is included). Further details about the test and the first outcomes are presented in this paper.

Trästaden ett uthålligt koncept – utvärdering av 10 års drift visar hur ett flervåningshus byggt med trästomme fungerar på lite längre sikt. Projektet genomfördes under 2005-2006 och har inneburit att uppföljningar har gjorts på plats i husen på Välludden i Växjö. Inomhusmiljön, verklig energianvändning under 10 år samt att de exteriöra trädetaljerna har undersökts och dokumenterats. Projektet har genomförts som ett samfinanseriat forskningsprojekt inom ramen för Stiftelsen IVL med Södras Skogsägarnas Stiftelse för Forsknings, utveckling och Utbildning som medfinansiär. SP Sveriges Tekniska Forskningsinstitut har deltagit i undersökningarna som rör innemiljön samt utvärdering av de exteriöra trädetaljerna. Södra har deltagit med förvaltande personal på plats i Välluddenhusen.

Since 1994 there are restrictions in Sweden on the use of chromium and arsenic containing wood preservatives. These preservatives are now in principle allowed for use in ground contact and water only. The use of chromium and arsenic free preservatives has increased and dominates the Swedish market for commodities above ground (Nordic wood preservation class AB). As the knowledge of the performance of these preservatives is limited, a field trial was set up in order to get more information about the durability in ground and above ground, discolouration by staining fungi, leaching, weathering and corrosion on fasteners in contact with the treated wood. Samples were treated according to class AB in commercial treating plants with the following preservatives: Basilit Bauholz KVD, Impralit KDS, Kemwood ACQ 1900, Tanalith E, Wolmanit CX-S and Wolmanit CX-8. Untreated spruce and heartwood of pine and larch were also included in the trial. In addition to testing according to EN 252 and ENV 12037 (lap-joint), both somewhat modified, testing was also carried out according to methods specially designed for this trial. After five years exposure the results show that: · No treated samples exposed above ground have yet been attacked and very few untreated samples only have been severely attacked by wood destroying fungi. There is thus some concern that the methods used, and in particular the lap-joint method, are not suitable for above ground testing in temperate climates. · The tests in ground indicate that with increasing copper content in the treated wood the better is the performance. · Heartwood of larch performs better than heartwood of pine in the in ground tests. On contrary, heartwood of pine shows better decay resistance than heartwood of larch in the above ground tests. · All samples are more or less attacked by bluestain fungi. Untreated samples are severely attacked. · Stainless steel has the best performance against corrosion. Wood treated with Kemwood ACQ 1900 and Wolmanit CX-8 seems to accelerate the corrosion of most other fastener materials. · The leaching of the chromium and arsenic free preservatives seems to be substantial whereas the leaching from CCA-treated references is little or moderate. For wood preservatives containing copper and an organic active ingredient, copper seems to be less susceptible to leaching then the organic component for which not only leaching but also chemical decomposition may take place.

Lignin is a natural polymer and one of the most abundant materials on earth. Despite this fact, lignin is often viewed as a by-product in chemical pulp processing and the use of lignin as a sustainable material is low. However, research and public awareness of sustainability have opened up new possibilities for using lignin as a material. In this study, Kraft softwood lignin was reacted with acetic and propionic anhydride to synthesize esterified lignin. Reactions were performed at 80 °C. The product was analyzed using IR, DSC and processability parameters, such as melt viscosity. The product was then blended with LDPE and extruded into composite films. The films were analyzed using FTIR and TGA, and the mechanical properties were determined by tensile tests. Preliminary results are positive and further studies are planned to confirm the results and establish the range of properties attainable.

The aim of this work was to achieve a better understanding of the wettability, i.e. liquids wetting and sorption characteristics (or penetrability), of acetylated Southern yellow pine (SYP) including probable differences in such characteristics between early- or latewood. Matched samples of acetylated and untreated SYP boards were prepared. The wettability of the samples were measured by the Wilhelmy technique using standard probe liquids as well as two different sample coatings, a cationic knot sealer and an acrylic based dye. The results showed that latewood regions of the acetylated wood had a noticeably lower uptake of the non-polar low surface tension liquid octane as well as the polar high surface tension liquid water compared with latewood of the untreated controls. Contact angle analysis based on the Lewis acid-base concept indicated that the acetylated wood is predominantly Lewis basic. A preferential wetting of the knot sealer was observed on the acetylated wood.

Two series of full scale fire tests of wooden facades according to the Swedish test SP Fire 105 are presented, one series for different shares of untreated wood (partial wood and structural fire protection with a fire shield above the window) and another series for fire retardant treated, FRT, wood. The results are compared with data from the Single Burning Item test and the cone calorimeter. For FRT wood, the need for verification of the weather durability of the treatment is stressed and a new European technical specification CEN/TS 15912 presented. The need to use fire stops behind multi-storey façade claddings to avoid fire spread in the cavities is underlined and the possibilities of fire safety design with sprinklers is briefly presented.