Effects of Char Produced from Burning Wood Combustibles on Thermal Pyrolysis

Self Cite

The heat release rate (HRR) of fires can be determined from the relationship between the thermal pyrolysis rate of combustibles and the effective heat of combustion. To accurately determine the thermal pyrolysis rate of combustibles, it is important to understand the heat of reaction of combustibles. However, this parameter is difficult to measure for combustibles, such as wood, that produce charring during combustion because they undergo a multi-step pyrolysis reaction. In this study, the ISO 5660-1 standard method was used to perform cone calorimetry experiments to understand how the HRR is affected by the heat of reaction heat and charring properties of combustibles. To this end, the HRR calculated using FDS computational analysis was compared to the measured value from the ISO 5660-1 cone calorimetry experiments. A dehydrated Douglas-fir, an evergreen tree of the pine family, was used as a combustible material. The cone calorimetry experiment and FDS computational analysis results confirmed that increases in the heat of reaction and charring properties were directly correlated with the decrease in the HRR.

unclassified

Effect of Heat of Reaction and Charring Properties on Heat Release Rate during Combustion

Lee¹,

Park²

2021

Self Cite

Experimental Study on Combustion and Fire Smoke Characteristics of Wallpapers using Smoke Density Chamber

Lee,

Ha,

Jeon

2023

During a fire, flames can quickly spread throughout the room because the wallpaper covers the entire surface. Smoke generated from fire is a significant obstacle to evacuation. Therefore, it is essential to study the smoke characteristics of the wallpaper to ensure evacuation safety. This study used the ISO 5659-2 combustion chamber method to measure the smoke density over time with and without flame conditions using a 25 kW/m<sup>2</sup> radiation heat flux. The extinction coefficient represents the visibility in the smoke, and VOF4 shows the initial combustion smoke density characteristics. These two factors were derived from experiment results. Paper, cork, and cotton wallpapers were used as representative wallpapers. The results show that the maximum smoke density of all wallpapers was higher in the non-flame condition than in the flame condition. Under the flame condition, the maximum smoke density was measured in the order of cork, cotton, and paper. In the non-flame condition, the order was cotton, cork, and paper with the maximum smoke density. The extinction coefficient of wallpapers, except paper, exceeded 1.0 m<sup>-1</sup> in the flame condition, indicating that the smoke density provides visibility of 1-2 m under fire.

Experimental Study on the Effect of Flow around Solid Combustibles and Thermal Thickness on Heat Release Rate Characteristics

Hong¹,

Seo²,

Park³

2020

In this study, an ISO 5660-1 cone calorimeter experiment was conducted to examine the effects of changes in flow and thermal thickness around solid combustibles on heat release rate characteristics. Polymethyl methacrylate (PMMA) is a solid combustible material that does not generate char during the combustion reaction. Hence, it was selected for the experiment, and the thermal penetration depth was calculated to distinguish the thermal thickness of PMMA. Furthermore, the thermal decomposition characteristics were analyzed by measuring the heat release rate measured during the combustion of PMMA. This was performed after generating the forced flow around the combustibles by setting the duct flow of the cone calorimeter to 12, 24, and 40 L/s. The results confirmed that the thermal release rate of the thermally thin combustible material was not significantly affected by the change in the surrounding flow. Hence, the thermally thick combustible material was significantly affected by the change in the flow rate.