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Compressed air foam (CAF) and compressed nitrogen foam (CNF) have been widely used for storage tank fire suppression, benefiting from their highly effective extinguishing performance. Mass loss rate is an important parameter to evaluate the stability of foam and an important factor to influence the suppression efficiency of foam. In this work, mass loss mechanisms including drainage and evaporation of two types of foams under a fixed radiation source were experimentally studied to reflect the foam fire suppression efficiency. It was observed that the foam drain rate is directly proportional to the foam mass, with a slight relation to the irradiance when irradiance is lower than 20 kW/m2. Once the irradiance reaches 30 kW/m2, the drain rate increases significantly. For evaporation, as expected from the established theoretical model, the evaporation rate shows a positive relationship with the irradiance level. However, there is no relationship between foam evaporation rate and the initial foam thickness. Through the experimentally measured evaporation rate, the average foam absorptivity is calculated to be approximately 0.63 ± 0.07 for both foams at an expansion ratio (ER) of 10. A comparative analysis of mass loss characteristics in the two types of foam was also undertaken. It was found that the two types of foam have distinct drain rates due to their different foam stability caused by the different expanded gas properties. However, they have a similar evaporation rate. In addition, the foam destruction rate and time to ignite the underlying fuel were measured, and a linear relationship between ignition time and initial foam height was found with a slope of 1.7 ± 0.2. The results demonstrate that CNF has a better fire suppression efficiency, which can be attributed to the better stability of the foam and the nitrogen released by broken bubbles, which inhibits ignition. The work presented here reveals the different functional mechanisms of compressed air/nitrogen foam and presents useful information that could enhance our understanding of the fire suppression effects of fire extinguishing foam. [ABSTRACT FROM AUTHOR]

The original article can be found online at https://doi.org/10.1007/s10694-022-01332-0.Correction to: Fire Technology https://doi.org/10.1007/s10694-022-01332-0In this article, Sect. 3.2 "The reasons for this are described in Sect. 2.1" should be changed to "The reasons for this are described in Sect. 2.2". The author group information is missing in this article and should have read as in this Correction.The original article has been corrected.By Fengyuan Tian; Kun Wang; Jun Fang; Hassan Raza Shah; Xuqing Lang; Shanjun Mu; Jinjun Wang and Jingwu WangReported by Author; Author; Author; Author; Author; Author; Author; Author [Extracted from the article]

Recently, water has been employed as a supportive agent for the preparation of multiple suppressing agents including aqueous film forming foams (AFFF), which is combined with different kinds of gases for its various applications. In this study, the water mist is chosen for the gas-suppressing agent such as carbon dioxide. Our work investigated the suppression effects of water droplets on the n-heptane pool fire, and its mixture with carbon dioxide, respectively. The size and frequency of droplets with their effect on temperature and suppression was compared to observe the difference in the suppression. Initially, it was found that the droplets having a larger droplet size were found to be more efficient as compared to the smaller droplets with respect to the heat release rate, temperature, and radiation. Afterwards, a mixture of water droplets and carbon dioxide was simultaneously discharged to compare the difference between these two suppressing agents. It was found that the synergistic effect of the mixture has higher advantages over the use of only water suppression. It helps reduce the hot gases that surround the pool fire and allows the water mist to travel efficiently towards the fuel. Both suppression mechanisms were set to similar initial parameters that lead to different outcomes. [ABSTRACT FROM AUTHOR]