Surface fire blocking effect under different pine needle bulk densities and water coverage levels

doi:10.16265/j.cnki.issn1003-3033.2026.09.0419

Abstract

Abstract:

To evaluate the barrier effectiveness of firebreaks in forest firefighting, dead fallen needles of Pinus massoniana were used as fuel, and an experimental platform for surface fire spread was constructed. Six water coverage levels and three fuel bulk densities were set to investigate the barrier effect of firebreaks on fire spread. The results show that, based on the flame spread process and internal temperature distribution, the barrier effects of water-covered firebreaks can be categorized as successful or failed. The success of blocking is closely related to the smoldering propagation process at the bottom of the fuel bed. The actual barrier effectiveness is significantly influenced by the water coverage level and fuel bed bulk density. Successful blocking is achieved when the water coverage level is sufficient to maintain cooling and wetting within the firebreak and to suppress smoldering propagation at the bottom of the fuel bed and subsequent reignition. As the water coverage level increases, a higher moisture content is maintained within the firebreak, smoldering propagation is more effectively suppressed, and the blocking effectiveness is improved. For bulk densities of 33.33, 42.85, and 100 kg/m³, the corresponding critical water coverage levels required for successful blocking are 3.0, 2.0, and 1.0 L/m², respectively. The barrier effect is also improved by a higher fuel bed bulk density, mainly because a higher bulk density leads to lower porosity and poorer oxygen supply conditions. Meanwhile, the bulk density of the fuel bed modifies the flame length and tilt angle during fire spread, ultimately affecting the radiation intensity behind the firebreak.

Key words: bulk density, water coverage level, surface fire, barrier effectiveness, pinus massoniana litter combustion bed, water-covered firebreak

CLC Number:

X954农、林、渔业安全

Kong Weiguang, Pan Yu, Zhang Jinlian, Guo Weihua, Zhao Jinlong. Surface fire blocking effect under different pine needle bulk densities and water coverage levels[J]. China Safety Science Journal, 2026, 36(9): 248-255.

Figures/Tables 11

Fig.1

Table 1

Fig.2

Fig.3

Table 2

Fig.4

Fig.5

Fig.6

Fig.7

Fig.8

Fig.9

References 27

[1]	黄锐, 王卓泰. 2010-2022年我国森林火灾时空分布规律[J]. 东北林业大学学报, 2025, 53(9):20-25.
	Huang Rui, Wang Zhuotai. Spatio-temporal distribution patterns of forest fires in China from 2010 to 2022[J]. Journal of Northeast Forestry University, 2025, 53(9): 20-25.
[2]	王诗琪, 孙智, 陈涛, 等. 基于森林火灾风险的AG600消防飞机机场选址研究[J]. 控制与决策, 2026, 41(2):531-542.
	Wang Shiqi, Sun Zhi, Chen Tao, et al. Location-allocation optimization of AG600 amphibious airtankers considering forest fire risk[J]. Control and Decision, 2026, 41(2): 531-542.
[3]	李国辉, 戎凤仪, 李艳志, 等. 森林火灾扑救技术与装备研究进展[J]. 消防科学与技术, 2025, 44(9):1265-1 273.
	Li Guohui, Rong Fengyi, Li Yanzhi, et al. Research progress on forest fire suppression techniques and equipment[J]. Fire Science and Technology, 2025, 44(9): 1 265-1 273.
[4]	杜秋洋. 美国加州山火为何如此“狂虐”[J]. 中国应急管理, 2025(2):38-39.
[5]	武金模. 外界风和坡度条件下地表火蔓延的实验和模型研究[D]. 北京: 中国科学技术大学, 2014.
	Wu Jinmo. Experimental and theoretical study on surface fire spread under effect of wind and slope[D]. Beijing: University of Science and Technology of China, 2014.
[6]	Fang J B, Steward F R. Flame spread through randomly packed fuel particles[J]. Combustion and Flame, 1969, 13(4): 392-398. doi: 10.1016/0010-2180(69)90108-4
[7]	Simeoni A, Bartoli P, Torero J L, et al. On the role of bulk properties and fuel species on the burning dynamics of pine forest litters[J]. Fire Safety Science, 2011:1401-1 414.
[8]	陈松, 刘乃安, 谢小冬, 等. 可燃物填充比对火蔓延影响的实验研究[J]. 火灾科学, 2021, 30(2):92-97.
	Chen Song, Liu Naian, Xie Xiaodong, et al. Experimental study on the effect of fuel packing ratio on fire spread[J]. Fire Safety Science, 2021, 30(2): 92-97.
[9]	He Qianqian, Liu Naian, Xie Xiaodong, et al. Experimental study on fire spread over discrete fuel bed-Part I: effects of packing ratio[J]. Fire Safety Journal, 2021, 126: DOI:10.1016/J.FIRESAF.2021.103520.
[10]	何迁迁. 环境风作用下离散燃料火蔓延的实验与机理研究[D]. 北京: 中国科学技术大学, 2022.
	He Qianqian. Fire spread over discrete fuel under wind conditions: experimental and theoretical study[D]. Beijing: University of Science and Technology of China, 2022.
[11]	Penney G, Habibi D, Cattani M, et al. Calculation of critical water flow rates for wildfire suppression[J]. Fire, 2019, 2(1):DOI:10.3390/fire2010003.
[12]	余威, 陆强. 我国森林灭火技术装备应用现状与发展趋势[J]. 消防科学与技术, 2022, 41(3):421-424.
	Yu Wei, Lu Qiang. Application status and development trend of forest fire fighting extinguishing technology in China[J]. Fire Science and Technology, 2022, 41(3): 421-424.
[13]	杨小雨, 邢卓琳, 苏子康, 等. 森林火灾多机协同阻燃剂布撒任务调度规划[J/OL]. 北京航空航天大学学报:1-18[2026-05-12].https://doi.org/10.13700/j.bh.1001-5965.2025.0358.
	Yang Xiaoyu, Xing Zhuolin, Su Zikang, et al. Coordinated dispatch plan of multiple fire-fighting aircraft for dispersing retardant[J/OL]. Journal of Beijing University of Aeronautics and Astronautics: 1-18[2026-05-12].https://doi.org/10.13700/j.bh.1001-5965.2025.0358.
[14]	Emmons H W. Fundamental problems of the free burning fire[J]. Symposium (International) on Combustion, 1965, 10(1): 951-964. doi: 10.1016/S0082-0784(65)80238-7
[15]	郭瀚文, 高云骥, 陶浩文, 等. 不同坡度条件存在隔离带燃料床地表火蔓延试验模拟研究[J]. 安全与环境学报, 2024, 24(6):2197-2 205.
	Guo Hanwen, Gao Yunji, Tao Haowen, et al. Investigation of surface fire spread in the presence of fire break with variable slope angles[J]. Journal of Safety and Environment, 2024, 24(6): 2 197-2 205.
[16]	王叁. 川西南地区主要针叶林可燃物空间分布及潜在火行为[D]. 北京: 北京林业大学, 2016.
	Wang San. Spatial distribution of fuel and potential fire behavior of main coniferous forests in Southwest Sichuan[D]. Beijing Forestry University, 2016.
[17]	郭妍. 森林地表火蔓延的实验模拟和预测模型研究[D]. 哈尔滨: 东北林业大学, 2024.
	Guo Yan. Experimental simulation and prediction model study of forest surface fire spread[D]. Harbin:Northeast Forestry University, 2024.
[18]	Rothermel R C. A mathematical model for predicting fire spread in wildland fuels[R]. USDA Forest Service, Research Paper INT-115, 1972.
[19]	Balbi J H, Viegas D X, Rossi J L, et al. Surface fires: no wind, no slope, marginal burning[J]. Journal of Environmental Science and Engineering A, 2014, 3(2): 73-86.
[20]	张玉春, 孔林毅, 郭瀚文, 等. 燃料载荷和含水率对平坡地表火蔓延影响实验研究[J]. 消防科学与技术, 2022, 41(2):261-265.
	Zhang Yuchun, Kong Linyi, Guo Hanwen, et al. Experimental study on the effects of fuel load and water content on surface fire spread over flat fuel bed[J]. Fire Science and Technology, 2022, 41(2): 261-265.
[21]	Qin Yunzhu, Chen Yuying, Zhang Yichao, et al. Modeling smothering limit of smoldering combustion: oxygen supply, fuel density, and moisture content[J]. Combustion and Flame, 2024, 269:DOI:10.1016/j.combustflame.2024.113683.
[22]	Morvan D, Dupuy J L. Modeling of fire spread through a forest fuel bed using a multiphase formulation[J]. Combustion and Flame, 2001, 127(1/2): 1 981-1 994.
[23]	Guo Hanwen, Xiang Dong, Kong Linyi, et al. Upslope fire spread and heat transfer mechanism over a pine needle fuel bed with different slopes and winds[J]. Applied Thermal Engineering, 2023, 229:DOI:10.1016/j.applthermaleng.2023.120605.
[24]	Morandini F, Simeoni A, Santoni P A, et al. A model for the spread of fire across a fuel bed incorporating the effects of wind and slope[J]. Combustion Science and Technology, 2005, 177: 1 381-1 418.
[25]	Liu Naian, Wu Jinmo, Chen Haixiang, et al. Effect of slope on spread of a linear flame front over a pine needle fuel bed: experiments and modelling[J]. International Journal of Wildland Fire, 2014, 23: 1 087-1 096.
[26]	Hamilton D C, Morgan W R. Radiant-interchange configuration factors[R]. NACA Technical Notes, Purdue University, 1952.
[27]	Lozano J, Tachajapong W, Pan Hansheng, et al. Experimental investigation of the velocity field in a controlled wind-aided propagating fire using particle image velocimetry[J]. Fire Safety Science, 2008, 9: 255-266. doi: 10.3801/IAFSS.FSS.9-255

试验工况		覆盖水平/(L/m²)
试验工况		0.5	1.0	1.5	2.0	2.5	3.0
堆积密度/ (kg/m³)	33.33	×	×	×	×	×	√
	42.85	×	×	×	√	√	√
	100	×	√	√	√	√	√