ABSTRACT The method for conducting heating tests on test specimens in a vertical orientation using a cone calorimeter is recommended in ISO 5660 Annex E. Although this standard defines the ignitor position, no experimental basis has been found. A previous study suggests that the specified position may not necessarily be optimal. Furthermore, the spark orientation is not specified in ISO 5660 Annex E, and no studies investigating the effect of ignitor spark have been found. Therefore, this study conducted cone calorimeter tests by varying the position and orientation of the ignitor spark to investigate their effects on experimental results. Three experimental series, (1) experiments with detailed variations in the ignitor position using flexible polyurethane foam as the test specimen, (2) experiments altering the ignitor orientation at representative ignitor positions using plywood as the test specimen, and (3) experiments using various materials for the test specimen at representative ignitor positions were conducted. In experimental series (3), two types of wooden materials, polyvinyl chloride board, and gypsum board with wallpaper were selected as test specimens. The experimental results were compared such as time to ignition, peak heat release rate, cumulative heat release, and surface temperature at ignition. The results indicated that the ignitor position recommended in ISO 5660 Annex E and a horizontal ignitor orientation (perpendicular to the airflow) are suitable for burning test materials and obtaining stable test results.
Komiya et al. (2026) studied this question.