[1] Univ Perugia, Fac Engn, Inst Energy Sci, I-06125 Perugia, Italy
[2] Cornell Univ, Dept Civil & Environm Engn, Ithaca, NY 14853 USA
[3] Ruhr Univ Bochum, D-4630 Bochum, Germany
[4] Natl Inst Stand & Technol, Build & Fire Res Lab, Gaithersburg, MD 20899 USA