CSIRO PUBLISHING International Journal of Wildland Fire https://doi.org/10.1071/WF20117 Laboratory study on the suppression of smouldering peat wildfires: effects of flow rate and wetting agent Muhammad A. Santoso A, Wuquan Cui A, Hafiz M. F. Amin A, Eirik G. Christensen A, Yulianto S. Nugroho B and Guillermo Rein A,C ADepartment of Mechanical Engineering and Leverhulme Centre for Wildfires, Environment and Society, Imperial College London, London, SW7 2AZ, UK. BDepartment of Mechanical Engineering, Universitas Indonesia, 16424, West Java, Indonesia. CCorresponding author. Email:
[email protected] Abstract. The application of water, or water mixed with suppressants, to combat wildfires is one of the most common firefighting methods but is rarely studied for smouldering peat wildfire, which is the largest type of fire worldwide in term of fuel consumption. We performed experiments by spraying suppressant to the top of a burning peat sample inside a reactor. A plant-based wetting agent suppressant was mixed with water at three concentrations: 0% (pure water), 1% (low concentration), and 5% (high concentration), and delivered with varying flowrates. The results showed that suppression time decreased non-linearly with flow rate. The average suppression time for the low-concentration solution was 39% lower than with just water, while the high-concentration solution reduced suppression time by 26%. The volume of fluid that contributes to the suppression of peat in our experiments is fairly constant at 5.7 Æ 2.1 L kgÀ1 peat despite changes in flow rate and suppressant concentration. This constant volume suggests that suppression time is the duration needed to flood the peat layer and that the suppressant acts thermally and not chemically.