Ignition of Mulch Beds Exposed to Continuous-Wind Driven Firebrand Showers
Samuel L. Manzello, Sayaka Suzuki, Koji Kagiya, Junichi Suzuki, Yoshihiko Hayashi
A series of experiments were conducted to examine ignition of mulch beds to continuous, wind-driven firebrand showers. Shredded hardwood mulch, fitted in beds 1.2 m by 1.2 m with a thickness of 51 mm, was attached to a non-combustible re-entrant corner assembly. The mulch/re-entrant corner assembly was then exposed to continuous, wind-driven firebrand bombardment generated by the NIST full-scale Continuous Feed Firebrand Generator (aka the NIST full-scale Continuous Feed Dragon) installed in the Fire Research Wind Tunnel Facility (FRWTF) at the Building Research Institute (BRI) in Japan. The time to reach sustained flaming ignition (FI) of shredded hardwood mulch beds exposed to continuous wind-driven firebrand showers was determined as function of mulch bed moisture content, and applied wind speed. These experiments have determined ignition behavior of mulch beds installed in realistic building configurations under wind-driven firebrand showers. The accumulation of firebrand was a key factor to produce ignition.