Study on the Influence of Expansion Ratio on the Effectiveness of Foam in Suppressing Forest Surface Fires

Firefighting foam is widely recognized for its excellent fire suppression performance. However, research on the effect of foam expansion ratio on the suppression efficiency of forest surface fires remains limited. In this study, the expansion ratio was adjusted by varying the air-to-liquid ratio in...

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Main Authors: Haiyan Wang, Junzhao Zhang, Hongbin Zhong, Lei Chen
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Fire
Subjects:
Online Access:https://www.mdpi.com/2571-6255/8/5/171
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author Haiyan Wang
Junzhao Zhang
Hongbin Zhong
Lei Chen
author_facet Haiyan Wang
Junzhao Zhang
Hongbin Zhong
Lei Chen
author_sort Haiyan Wang
collection DOAJ
description Firefighting foam is widely recognized for its excellent fire suppression performance. However, research on the effect of foam expansion ratio on the suppression efficiency of forest surface fires remains limited. In this study, the expansion ratio was adjusted by varying the air-to-liquid ratio in a compressed air foam system, and laboratory-scale foam suppression experiments were conducted. Key performance indicators, including extinguishing coverage time, internal cooling rate, and resistance to reignition, were systematically measured. The effects of expansion ratio on the diffusion and penetration behavior of foam on the fuel bed surface were then investigated to understand how these characteristics influence suppression performance. The results indicate that both excessively low and high expansion ratios can weaken fire suppression effectiveness. Low-expansion foam, characterized by low viscosity and high water content, exhibits strong local penetration and cooling capabilities. However, it struggles to rapidly cover the fuel bed surface and isolate oxygen, thereby reducing the overall suppression efficiency. In contrast, high-expansion foam has greater viscosity, allowing it to spread across the fuel bed surface under pressure gradient forces and form a stable coverage layer, effectively limiting the oxygen supply required for combustion. However, its limited depth penetration and lower water content reduce internal cooling efficiency, increasing the risk of reignition. The optimal expansion ratio was determined to be 15.1. Additionally, increasing the liquid supply flow rate significantly improved suppression performance; however, this improvement plateaued when the flow rate exceeded 10 L/min.
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spelling doaj-art-be5fa98ca02445b8bca133993860eb492025-08-20T03:14:31ZengMDPI AGFire2571-62552025-04-018517110.3390/fire8050171Study on the Influence of Expansion Ratio on the Effectiveness of Foam in Suppressing Forest Surface FiresHaiyan Wang0Junzhao Zhang1Hongbin Zhong2Lei Chen3School of Emergency Management and Safety Engineering, China University of Mining and Technology, Beijing 100083, ChinaSchool of Emergency Management and Safety Engineering, China University of Mining and Technology, Beijing 100083, ChinaSchool of Emergency Management and Safety Engineering, China University of Mining and Technology, Beijing 100083, ChinaSchool of Emergency Management and Safety Engineering, China University of Mining and Technology, Beijing 100083, ChinaFirefighting foam is widely recognized for its excellent fire suppression performance. However, research on the effect of foam expansion ratio on the suppression efficiency of forest surface fires remains limited. In this study, the expansion ratio was adjusted by varying the air-to-liquid ratio in a compressed air foam system, and laboratory-scale foam suppression experiments were conducted. Key performance indicators, including extinguishing coverage time, internal cooling rate, and resistance to reignition, were systematically measured. The effects of expansion ratio on the diffusion and penetration behavior of foam on the fuel bed surface were then investigated to understand how these characteristics influence suppression performance. The results indicate that both excessively low and high expansion ratios can weaken fire suppression effectiveness. Low-expansion foam, characterized by low viscosity and high water content, exhibits strong local penetration and cooling capabilities. However, it struggles to rapidly cover the fuel bed surface and isolate oxygen, thereby reducing the overall suppression efficiency. In contrast, high-expansion foam has greater viscosity, allowing it to spread across the fuel bed surface under pressure gradient forces and form a stable coverage layer, effectively limiting the oxygen supply required for combustion. However, its limited depth penetration and lower water content reduce internal cooling efficiency, increasing the risk of reignition. The optimal expansion ratio was determined to be 15.1. Additionally, increasing the liquid supply flow rate significantly improved suppression performance; however, this improvement plateaued when the flow rate exceeded 10 L/min.https://www.mdpi.com/2571-6255/8/5/171surface firecompressed air foam systemfoam expansion ratioliquid supply flow ratefire suppression effectiveness
spellingShingle Haiyan Wang
Junzhao Zhang
Hongbin Zhong
Lei Chen
Study on the Influence of Expansion Ratio on the Effectiveness of Foam in Suppressing Forest Surface Fires
Fire
surface fire
compressed air foam system
foam expansion ratio
liquid supply flow rate
fire suppression effectiveness
title Study on the Influence of Expansion Ratio on the Effectiveness of Foam in Suppressing Forest Surface Fires
title_full Study on the Influence of Expansion Ratio on the Effectiveness of Foam in Suppressing Forest Surface Fires
title_fullStr Study on the Influence of Expansion Ratio on the Effectiveness of Foam in Suppressing Forest Surface Fires
title_full_unstemmed Study on the Influence of Expansion Ratio on the Effectiveness of Foam in Suppressing Forest Surface Fires
title_short Study on the Influence of Expansion Ratio on the Effectiveness of Foam in Suppressing Forest Surface Fires
title_sort study on the influence of expansion ratio on the effectiveness of foam in suppressing forest surface fires
topic surface fire
compressed air foam system
foam expansion ratio
liquid supply flow rate
fire suppression effectiveness
url https://www.mdpi.com/2571-6255/8/5/171
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AT hongbinzhong studyontheinfluenceofexpansionratioontheeffectivenessoffoaminsuppressingforestsurfacefires
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