As a common thermal insulation material, glass wool board not only has good thermal insulation performance, but also performs well in sound absorption. The sound absorption performance of glass wool board is related to many factors, such as glass fiber diameter, bulk density, moisture content, whether the fiber is evenly distributed, etc. Below, Utesen glass wool manufacturers will explain to you the relationship between the bulk density of glass wool board and the sound absorption performance.
First of all, let's understand the bulk density and sound absorption coefficient of glass wool board.
The bulk density (density) of glass wool board refers to the weight contained in a unit volume, which is usually expressed in kilograms cubic meters (kg m). The bulk density mainly depends on the weight of the glass wool material and the arrangement of the fibers, usually between 30-200 kg m.
The sound absorption coefficient is a parameter that measures the ability of a material to absorb sound waves, and its value range is generally 0 to 1, with 0 representing complete reflection and 1 representing complete absorption.
Next, we will use glass wool sheets of the same thickness and different bulk densities to test the relationship between bulk density and sound absorption coefficient.
This time, a glass wool board with a thickness of 100mm and a bulk density of 32kg mkg mkg m was used to measure using the standing wave tube method, and the test range was 100 4000Hz, using 1 3 octaves. to verify the effect of bulk density on the sound absorption coefficient in different frequency bands. The results are shown in the figure below.
According to the measured data in the above figure, it can be seen that in the 100 400Hz section, with the increase of bulk density, the sound absorption coefficient also increases, and the comparison curve of the two bulk density samples of 32kg m and 48kg m is particularly obvious, and the sound absorption coefficient of high bulk density is relatively large. In the 400 1000Hz section, the sound absorption coefficient of the 32 kg m sample still increased rapidly, the sound absorption coefficient of the 48 kg m sample increased slowly, and the sound absorption coefficient of the 80 kg m sample decreased. In the 1000 and 4000 Hz range, the sound absorption coefficients of the three samples did not change much.
It can be seen that the change of the bulk density of glass wool board has a greater impact on low frequency and less impact on high frequency. When the bulk density is too high, the sound absorption performance of medium and high frequencies has a tendency to decrease. This is because the over-dense glass wool board is more dense, the flow resistance is greater than the optimal flow resistance, and the sound absorption coefficient decreases. This is because the material is too dense per unit area, resulting in a shorter path for sound propagation, less sound energy attenuation, and worse sound absorption.
Therefore, when we absorb sound in the low frequency band, we can achieve better sound absorption by choosing high bulk densityWhen absorbing the sound in the middle frequency band, it is more appropriate to choose a glass wool board with a moderate bulk density;To absorb high-frequency sounds, it is more cost-effective to choose low-density glass wool panels. If you want to know more about glass wool in the future, please pay attention to Uetersen glass wool manufacturers.