Acoustic and Thermal Performance of Sustainable Pine Needle Fiber Panels With Integrated Micro-Perforated Panels for Eco-Friendly Building Applications Publisher



Bahiraei F ; Sheikhmozafari MJ ; Soltani P ; Mirzaei R ; Taban E
Source: Measurement: Journal of the International Measurement Confederation Published:2026

Abstract

This study investigates the acoustic and thermal properties of eco-friendly panels made from pine needle fibers, offering a sustainable alternative to conventional synthetic materials that pose environmental and health concerns. As global energy consumption increases and the demand for improved indoor acoustic comfort grows, these natural fiber panels present a promising solution for sustainable building applications. Pine needle fibers were treated and fabricated into panels with varying densities (300–600 kg/m3) and thicknesses [20–52]. Their sound absorption and thermal insulation properties were analyzed through experimental and modeling approaches. Acoustic performance was assessed using impedance tube measurements in accordance with ISO 10534–2 standards and predicted using the Delany-Bazley and Johnson-Champoux-Allard (JCA) models, while thermal conductivity was determined via the guarded hot plate method. Results indicate that increasing panel density enhances low-frequency sound absorption, while greater thickness shifts the absorption peak from 3150 Hz to 900 Hz, improving low-frequency performance. The optimal configuration panels with a density of 400 kg/m3 and a thickness of 60 mm achieved a sound absorption average (SAA) of 0.64 and an effective thermal conductivity (Keff) of 0.061 W/(m·K). The observed trend indicates that an increase in material density correlates with a rise in Keff, while an increase in thickness appears to inversely affect Keff. Moreover, the relatively low Keff values confirm the strong insulating capability of pine needle fibers, primarily due to their porous and heterogeneous internal structure, which traps air and reduces conductive heat transfer. These results demonstrate that pine needle fiber panels can effectively contribute to reducing heat loss and improving energy efficiency in buildings. The JCA model demonstrated higher accuracy in predicting acoustic performance, with a low error margin of 1.5–3%. Additionally, incorporating micro-perforated panels (MPPs) improved the sound absorption coefficient in low frequency (100–500 Hz) with a 50 mm air gap. The use of heterogeneous/parallel MPPs further enhanced sound absorption without increasing the absorber's overall thickness or required air gap. These findings underscore the potential of pine needle fiber panels as an environmentally friendly alternative to synthetic materials, meeting green building standards by providing both effective acoustic absorption and thermal insulation. © 2026 Elsevier Ltd