20.500.12556/DiRROS-28800 Burning of liquid pools and wood cribs in large fully developed timber compartment fires The contribution of exposed mass timber to compartment fire dynamics is often framed by prescribed fuel load density, implicitly assuming fuel-independent thermal feedback. This paper interrogates that assumption experimentally using full-scale cross-laminated timber (CLT) compartments with two exposed surfaces (ceiling and side wall) and a movable fuel; either a kerosene pool or a wood crib. High-resolution measurements of heat flux, in-depth timber temperatures, burning rates, opening flows, and gas species demonstrate that fuel chemistry and geometry strongly modulate oxidizer delivery and residence time, thereby governing radiative feedback, CLT burning rates, and external flaming. The pool fire exhibited pronounced radiative enhancement and transient oxidizer starvation near the timber until pool decay. In contrast, the crib burning rate was inhibited, while the CLT burned efficiently. Analysis of the Global Equivalence Ratio (GER) and air bypass ratio revealed significant excess oxygen in the outflow, indicating that entrained air did not permeate the crib but instead oxidized the CLT, leaving unreacted air due to short mixing timescales. Despite unchoked doorway conditions, the crib fire produced bypass ratios and external flaming fractions comparable to the pool fire. The work shows that fuel load and ventilation factors alone are insufficient to describe the mass timber compartment fire dynamics and the CLT performance (e.g. charring). The fuel chemistry, geometry, and placement interact significantly with the compartment geometry. Therefore, the role of the moveable fuel is fundamental, and care must be employed when extrapolating demonstrator experiment results to the fire safety design of mass timber buildings. compartment fires burning rates pool fires wood cribs protection of wood požari v oddelkih hitrost gorenja požari v bazenih lesene kletke zaščita lesa true false true Elsevier Angleški jezik Slovenski jezik © 2026 The Authors Neznano 2026-04-08 09:34:35 2026-04-08 10:03:52 2026-04-09 03:51:15 0000-00-00 00:00:00 2026 0 0 This special issue is based on the selection of works presented at the 15th International Symposium on Fire Safety Science (IAFSS 2026) str. 1-10 [article no.] 104739 Vol. 162 Jul. 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2026-03-20 62 1873-7226 10.1016/j.firesaf.2026.104739 273011203 https://www.sciencedirect.com/science/article/pii/S0379711226001074 1 66250559-331d-11f1-b941-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=42894 RAZ_Senez_Keon_2026.pdf RAZ_Senez_Keon_2026.pdf 1 9414D57653E10AD2489CA76E0F610939 d4a205dde99f94dd1b8c6d0c9d8a51d79a0f186dc277af4888cf53047219944e 75b3b8ee-3321-11f1-b941-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=42901 Zavod za gradbeništvo Slovenije 0 0 0