The Permeability of a Soil Termite [Macrotermes gilvus (Hagen, 1858)] Fungus Comb as a Porous Medium

In the field of biomimicry, termite mounds serve as a source of inspiration for engineers and architects involved in designing environmentally friendly buildings. For this study, baseline data were collected on the permeability properties of a biological porous material—a termite fungus comb. This study aimed to determine the air permeability of the comb by conducting experiments involving an air flow through an internal pipe and analyzing the effects of different air flow velocities with Reynolds numbers ranging from 15,000 to 71,000. Through the use of image processing, a detailed geometric structure was observed. The specimens have a porosity ranging from 52% to 61%, indicating that they are highly porous and have large pores. There are also variations in the size of each specimen associated with the equivalent diameter, with an average value of 5.16 mm. In addition, the results demonstrate that the tested specimens' permeability values varied from 1.2724 x 10^-7 to 3.9828 x 10^-7 m², with an average value of 2.235 x 10^-7 m², as determined by the Forchheimer equation. Although this study was the first to characterize a termite fungus comb, it is recommended that additional research and evaluations be conducted to thoroughly investigate the characteristics and capabilities of this uncommon biological structure. Translating the properties of termite combs to the architectural scale assumes that their porosity, air flow dynamics, and structural stability scale predictably. Challenges include material differences, environmental variability, and manufacturing precision. Limitations also arise from potential discrepancies in the thermal performance and durability when replicating biological structures with conventional construction materials.