It is resistance provided by the acoustic material to the airflow passing through it. It is one of the important parameter for predicting the acoustic performance of sound absorbing materials.

  • It is measured as per ASTM C522 / ISO 9053 standards and its unit is Ns/m4.
  • Generally, higher the density, higher is the airflow resistivity of the acoustic materials.
  • Flow resistivity values range between 1000 to 300000 Ns/m4.
  • Insulations used within partition cavities require a thickness that fills the entire cavity for optimal sound control performance. The density of the insulation has a negligible effect on the STC rating of a wall.