Abstract: To investigate the effects of natural deterioration on the thermal performance of wood components for heritage buildings, the functional groups and thermal stability of four samples of wood components for conservation buildings and Pinus yunnanensis were determined using Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC), and the effects of natural deterioration on these were discussed. The results showed that Hard Pines has better fire resistance than Soft Pines, even after natural deterioration. At the same time, the decomposition of lignin and hemicellulose occurs mainly during the natural deterioration of the wood components. Deteriorated timber of the Qing dynasty is more susceptible to pyrolysis as the lignin is reduced and the temperature required for both the drying, and solid phase combustion stages is significantly advanced. In addition, the more severe the insect damage, the lower the cellulose of the deteriorated timber and the consequent reduction in heat release. At the same time, the more unstable the chemical structure of the wood components, the lower the temperature required for the drying phase of the deteriorated timber and the more intense the pyrolytic reaction.

Key words: natural deterioration, heritage building, fourier transform infrared spectroscopy, differential scanning calorimetry