Correlation coefficients computed with the linear regression model proposed in [6]. The first bar represents the performance of the best fitting reduced model to reproduce the response variable (flame surface at −5 CAD). The correlation coefficient between flame surface and the best fitting model is equal to 0.76. The other bars show the correlation coefficients between flame surface and each variable independently from the other variables: 0.72 for EC-HF-SP, 0.49 for UX and 0.34 for ER-SP.