earticle

영어

This study experimentally evaluated the long-term thermal degradation of expanded polystyrene (EPS) insulation collected from aged buildings. Thirty-five field samples with service lives ranging from 13 to 31 years were tested using the heat flow meter method in accordance with ISO 8301 and KS L 9016 to measure thermal conductivity (λ) and density (ρ). The measured thermal conductivity varied between 0.037 and 0.050 W/(m·K), with an average of 0.044 W/(m·K), representing approximately a 2–20% increase compared with the KS reference values for new EPS. The average density decreased by about 40% relative to the initial reference level. A strong negative correlation was observed between density and thermal conductivity (r = –0.732, p < 0.05), while a weak-to-moderate positive relationship was identified between density reduction and the increase in thermal conductivity (r = 0.41, p < 0.05). These findings suggest that density loss and microcell structural degradation are likely major contributing factors to the thermal performance degradation of aged EPS insulation. The regression models derived from this study provide foundational reference data for establishing correction factors that reflect the degraded thermal properties of aged insulation in building energy performance assessments and the green remodeling applications.