Sound absorption properties of different green wall systems

Façade of the buildings generally consists of acoustically rigid materials. They reflect or scatter sound emitting from sound sources especially main roads thus affects sound environment in a negative way. Applying green walls can be nature-based solution to these urban scale noise. The aim of this research is to compare green wall systems in terms of sound absorption and to determine which one is more effective. Sound absorption at normal incidence of 8 different green wall systems measured via impedance tube in accordance with TS ISO EN 10534-2 standard for 50-6400 Hz. The ivy type, evergreen Hedera Helix plant was used. Potting soil or felt or rock wool was used as a growth medium. As a result, it was seen that the sound absorption of the 'plant + 20 cm potting soil + 10 cm air gap' green wall system was higher than the others. It is followed by the system with 'plant + 20 cm potting soil', 'plant + 3 cm felt + 10 cm air gap' and 'plant + 3 cm rock wool + 10 cm air gap' systems. The sound absorption value was found to be lowest when the plant was applied only as a green façade.