Effect of intumescent coating on the charring rate of nail-laminated timber

Abstract

Intumescent coating was studied relative to the fire performance of nail-laminated timber. Three NLT specimens were coated with three different intumescent coating thicknesses (1, 2, and 3 mm) in even-numbered laminae and compared to uncoated NLT specimens. As a result of the coating, the internal temperature of the coated specimen increased more slowly than that of the uncoated specimen. The average charring rate of the intumescent coating specimen was reduced by 12.8% (1-mm thickness), 14.1% (2-mm thickness), and 15.4% (3-mm thickness) compared with the uncoated specimen. However, statistical analysis showed there was no significance between 1-, 2-, and 3-mm coating thicknesses. The combustion of wide surfaces of timber laminae between the plywood was delayed due to the coated plywood, and the timber laminae became a one-dimensional charring rate problem. Therefore, if even laminae are coated with an intumescent, then the NLT can be designed with a one-dimensional charring rate condition.

Fire resistance of structural wooden walls covered by gypsum and diatomite board

“…The gas injected into the fire jet is automatically controlled so that the internal temperature of the furnace follows the standard temperature curve of ISO 834-1 (1999). It is the same as the experimental equipment used by Pang et al (2022), except for the specimen and the thermocouple installation. A specimen (Table 1) was vertically installed on the furnace door, and the behavior of the specimen was visually observed through the glass window, as shown in Fig.…”

“…If fireproof boards are not used, structural wood walls for 2-h fire resistance can be designed based on the charring rate of the wood. In this case, 96 mm thick wood should be added for 2-hour fire resistance because the three-sided carbonization rate of the species is 0.78 to 0.80 mm/min (Pang et al 2022, EN 1995-1-2 2004. This is twice as thick as gypsum board (49 mm, No.…”

“…The second method is to protect the wood with fireproof boards or coatings so that the wood does not burn. Fire-resistant gypsum board is generally used, and the effect of intumescent coating for wood products has also been reported (Puri and Khanna 2017;Lucherini et al 2019;Pang et al 2022). The third method is to satisfy the fire performance using the above two methods together.…”