Joint investigation of vertical furnaces in Nordic countries

An investigation performed in the Nordic countries comprised comparison of the large vertical furnaces using both non- combustible and combustible specimens. The fire technological laboratories in Denmark, Finland and Norway participated in the former study and in addition to them the Swedish fire technological laboratory participated also in the latter. The comparison with non-combustible specimens was performed by measuring heat flux and radiation. The results obtained in both ways show that the differences between the furnaces in question are small. The heat flux was measured in the same way as in the international investigation which included ten laboratories and was made under the leadership of TNO. The Nordic results are very close to the mean value of this investigation. The comparison with combustible specimens was done by determining the fire resistance time of an accurately defined wooden wall structure. The obtained fire resistance times are comparatively close to each other and show a very good repeatability and reproducibility for the Nordic large vertical furnaces used in the study.