This final report summarises the work carried out during the project SI2.825082 financed by the European Commission – DG GROW. Within this project a theoretical Round Robin with the aim to analyse how the initial assessment method is interpreted by different laboratories, and the first and second phase of the initial testing activities to investigate the fire source, the design of the combustion chamber and secondary opening have been carried out. The final step in the project was an experimental Round Robin where four façade systems were tested at three different laboratories using the assessment method document, resulting in 24 tests. Additional tests were added to the project with funding from industrial partners. The tests were used to determine a calibration scheme and suitable performance criteria for classification. Furthermore, a substantial work has been done to ensure that the project is communicated in a good way to all stakeholders and Member States representatives.The theoretical Round Robin was performed with 29 laboratories, all members of European Group of Organisations for Fire Testing, Inspection and Certification (EGOLF). Over 200 questions covering the whole assessment method were asked, and thereafter analysed. The results show clearly which parts of the assessment method needs to be improved and clarified, as well as some practical details regarding the test method that had to be addressed.The first phase of the initial testing program defined the requirements of the fuel source and the combustion chamber. A large quantity of wood, of two different wood species (spruce and pine), had been acquired and thereafter characterised by measurement of dimensions, weight and moisture content. Over 4000 sticks have thus been density graded. After the selection of sticks to the different wood cribs a series of tests have been performed, mainly in accordance with the original test plan. Some modifications to the test plan were made during the course of the experimental study e.g., tests with a crib platform with either a grated or a solid floor. Also, a theoretical study through numerical modelling has been made to study the impact of changes of the combustion chamber geometry on the heat exposure to the test specimen. The simulations showed only small deviations between the regular and the enlarged combustion chamber. The changes of the geometry of the combustion chamber for the large exposure test can be done according to the results from the experimental program, it is beneficial for two reasons: it would make the preparatory work when mounting the test specimen simpler and it would ensure that falling parts will not damage the wood crib during a test.Based on the results a proposal has been made on the characteristics of the fuel source and the geometry and design of the combustion chamber, to be used in the second phase.During the second phase of the initial testing activities large and medium-scale exposure testing was performed on full façade geometries. The testing program including three repeatability tests in addition to gather information on variation in volume flow of the fan in medium-scale exposure as well as effects of the modified combustion chamber and wind in large-scale. From the repeatability tests it was decided to keep a constant height of the wood crib in large-scale due to otherwise large variations in exposure to the façade. Furthermore, the wind effects on the façade temperatures were significant even with a moderate wind of 1-2 m/s. At the end of the second phase three tests in medium and three tests in large-scale were done to investigate the effect of a secondary opening. It was indicated that asymmetrically placed opening would be the most appropriate placement.A short test series on alternative fuel source for the large exposure test was also performed where a propane diffusion burner was used instead of wood cribs. It was shown that if the combustion chamber would be reduced in height similar exposure to the façade could be achieved using the propane burner. There are several benefits with this alternative fuel source such as decreased height, less cleaning, higher safety and therefore less costs associated to10testing. For the medium exposure test the alternative gas burner described in DIN 4102-20 might be an appropriate alternative fuel source for the wood crib. However, no further investigations were made in this project in this regard.An update of the assessment method was made to take into account the latest information such as the repeatability tests and the second phase of the testing program. These changes such as the placement of the wood crib and the secondary opening was used in the experimental Round Robin.In tandem to this work, two surveys on falling parts were performed to find out the needs of Member States (MS) and setting criteria to be used during the Round Robin. Furthermore, an inquiry on the capacities for indoor and outdoor testing of different testing laboratories connected with EGOLF was made and is reported here.The work on the experimental Round Robin was completed in March 2024 and presentations of the tests and specimens are discussed in this report, more detailed information is available in the comparative documents. These include comparisons between tests on the same type of façade system at the different laboratories. This enables inter-laboratory comparisons for each monitored quantity and position. The inert tests are used to determine suitable calibration schemes for the medium and the large-scale exposure method, whereas the remaining tests are used to determine the performance criteria. Here it should be noted that average temperature is a more stable assessment criterion than a peak temperature or above a certain temperature during a certain time interval. The consortium would like to stress that arranging this type of Round Robin exercise is a severe logistic challenge which requires extensive planning.The project has been communicated through different channels. The project web page is the main communication channel where all reports and other documentation is published (https://www.ri.se/en/what-we-do/projects/european-approach-to-assess-the-fire-performance-of-façades). In addition to the webpage a YouTube channel is available showing a few of the tests and recent seminars, see webpage for a link.A Comments Handling Document has been kept and it includes almost 1000 comments that have been received during the project. These comments were handled continuously and communicated through the above-mentioned web page.