Determination of the properties of acoustic materials - airflow resistance of cellulose based insulation material

Pavel Rubáš,Jaroslav Výborný,R Černý,J Kočí,V Kočí

doi:10.1051/matecconf/201928202025

Pavel Rubáš, Jaroslav Výborný + Show 3 more

Open Access

https://doi.org/10.1051/matecconf/201928202025

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Abstract

The air flow resistance is a fundamental acoustic parameter to understanding the properties of cellulose based insulation material, it is useful for research and development to perform acoustic performance prediction and for calculation modelling. There is a connection between structure of cellulose based insulation material and its acoustic characteristics. Specific air flow resistance is also a parameter for the quality of cellulose based insulation which is used for factory production control because there is also strong connection between specific air flow resistance and density of produced material. Experimental measurement of airflow resistance has been performed according to the direct method of the EN 29053 standard where low and constant air flow is passed through cellulose based insulation with a specific section.

Highlights

In noise control engineering, airflow resistance is the most important input parameter for estimating sound absorption for porous type absorbers
The airflow coefficient is defined as the volume of air that flows in one second through a 1 m2 area of a porous material 1 m thick at a pressure difference between the two surfaces of 1 Pa
Airflow resistance r is a quantity describing the resistance put to the air flow by the embedded material at a pressure difference of 1 Pa between the two ends

Summary

Introduction

Airflow resistance is the most important input parameter for estimating sound absorption for porous type absorbers. It is defined as the ratio of the pressure drop to the airflow velocity through a test sample. In many papers and books the knowledge of the physical properties of porous and fibrous materials has been studied but there is no specific research of airflow resistance of cellulose based insulation materials [3-5]. The airflow resistance sensitivity of cellulose based insulation material to material characteristics, the specific weight, seems to be less known, at least from an experimental point of view. In this article a simple formula for the prediction of the airflow resistance as a function of the specific weight of cellulose based insulation is proposed

Meaning and measurement

Tested materials

Experimental tests and results

Findings

Conclusion