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 the diameter of glass fiber, bulk density, water content, and whether the fiber is evenly distributed. Next, Utsen glass wool manufacturers will explain the relationship between the bulk density of glass wool board and sound absorption performance.

First of all, let's first understand the volume weight and sound absorption coefficient of the glass wool board.

The bulk weight (density) of the glass wool board refers to the weight contained in the unit volume, usually expressed in kilograms/cubic meters (kg/m³). The bulk density mainly depends on the weight of the glass wool material and the fiber arrangement, usually between 30-200 kg/m³.

The sound absorption coefficient is a parameter that measures the ability of a material to absorb sound waves, and its value ranges from 0 to 1, where 0 represents complete reflection and 1 represents complete absorption.

Next, we will use the same thickness, different volume weight of glass wool board to test the relationship between volume weight and sound absorption coefficient.

This time, glass wool boards with 100mm thickness and bulk weight of 32kg/m³, 48kg/m³ and 80kg/m³ were used for measurement by standing-wave tube method. The test range was 100~4000Hz and 1/3 octave was adopted. 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 figure above, it can be seen that in the 100-400Hz range, the sound absorption coefficient also increases with the increase of bulk density. The comparison curves of 32kg/m³ and 48kg/m³ are particularly obvious, and the sound absorption coefficient of high bulk density is relatively large. In the 400-1000Hz range, the sound absorption coefficient of 32kg/m³ samples still increased rapidly, the sound absorption coefficient of 48kg/m³ samples increased slowly, and the sound absorption coefficient of 80kg/m³ samples decreased. In the range of 1000~4000Hz, the sound absorption coefficients of the three samples did not change much.

It can be seen that the change of the bulk density of the glass wool board has a greater impact on the low frequency and a smaller impact on the high frequency. When the bulk density is too high, the sound absorption performance of middle and high frequency tends to decline. This is because the over-high-density 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 in the unit area, the material is too dense will cause the path of sound propagation to become shorter, the sound energy attenuation is less, and the sound absorption effect is worse.

Therefore, when we absorb low frequency band sound, choose high volume weight can achieve better sound absorption effect; When absorbing the sound in the middle frequency band, it is more appropriate to choose the glass wool board with moderate volume weight; Absorption of high frequency band sound is, the choice of low volume weight glass wool board is more cost-effective.