N2 - It is well known that sound absorption and sound transmission properties of open porous materials are highly dependent on their airflow resistance values. Low values of airflow resistance indicate little resistance for air streaming through the porous material and high values are a sign that most of the pores inside the material are closed. The laboratory procedures for measuring airflow resistance have been stan- dardized by several organizations, including ISO and ASTM for both alternate flow and continuous flow. However, practical implementation of these standardized methods could be both complex and expensive. In this work, two indirect alternative measurement procedures were compared against the alternate flow standardized technique. The techniques were tested using three families of eco-friendly sound absorbent materials: recycled polyurethane foams, coconut natural fibres, and recycled polyester fibres. It is found that the values of airflow resistance measured using both alternative methods are very similar. There is also a good correlation between the values obtained through alternative and standardized methods. L1 - http://www.czasopisma.pan.pl/Content/101559/PDF/12_paper.pdf L2 - http://www.czasopisma.pan.pl/Content/101559 PY - 2013 IS - No 4 EP - 554 DO - 10.2478/aoa-2013-0064 KW - material characterization KW - airflow resistance KW - sound absorbing materials KW - eco-friendly materials A1 - del Rey, Romina A1 - Alba, Jesus A1 - Arenas, Jorge P. A1 - Ramis, Jaime PB - Polish Academy of Sciences, Institute of Fundamental Technological Research, Committee on Acoustics VL - vol. 38 DA - 2013 T1 - Technical Notes: Evaluation of Two Alternative Procedures for Measuring Airflow Resistance of Sound Absorbing Materials SP - 547 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/101559 T2 - Archives of Acoustics