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: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-04-01
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| Series: | Fire |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2571-6255/8/5/171 |
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| Summary: | 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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| ISSN: | 2571-6255 |