What factors affect the noise reduction effect of glass wool?

1. Material factors

- The density of glass wool has a significant impact on the noise reduction effect. Generally speaking, glass wool with a density of 10-48kg/m³ is more common. The higher the density, the better its sound absorption performance will be to a certain extent. For example, glass wool with a density of 32kg/m³ may have a higher sound absorption coefficient in the mid- and high-frequency bands than glass wool with a density of 12kg/m³.

- The thickness of glass wool is also a key factor. The thicker the thickness, the wider the sound frequency range it can absorb and isolate, and the more obvious the noise reduction effect. Generally speaking, 25mm thick glass wool has a better noise reduction effect than 15mm thick glass wool. If it is 50mm thick glass wool, it can reduce 3-5 decibels more noise than 25mm thick glass wool at certain frequencies.

2. Installation method and location

- If glass wool is installed on the wall, ceiling, etc., the degree of sealing will affect the noise reduction effect. If there are gaps that are not sealed during the installation process, the sound will propagate through these gaps, reducing the overall noise reduction performance. For example, when installing glass wool on the wall, fit the glass wool tightly to the wall and seal the edges with materials such as sealant to better play its noise reduction function.

- The layout of glass wool in the space is also important. For example, in a machine room, hanging glass wool on the ceiling in the shape of a sound-absorbing wedge can more effectively absorb reflected sound and reduce reverberation time than simply laying it flat on the ceiling, which may reduce noise by 2-3 decibels.

3. **Noise type

- For high-frequency noise, glass wool has a more significant noise reduction effect. Generally speaking, it can reduce high-frequency noise (above 2000Hz) by about 10-20 decibels. For example, in a factory workshop, some machines emit sharp high-frequency whistles. By installing glass wool on the walls of the workshop, this annoying high-frequency sound can be effectively reduced.

- For medium-frequency noise (200 - 2000Hz), glass wool can usually reduce 5 - 15 decibels. For example, the humming sound from the air conditioner outside the office can be blocked and absorbed by glass wool to a certain extent.

- For low-frequency noise (20 - 200Hz), the noise reduction effect of glass wool is relatively weak, and may only reduce 3 - 8 decibels. For example, the low-frequency roar produced by the ventilation equipment of large buildings, although glass wool has a certain noise reduction ability, the effect is not as obvious as for high-frequency and medium-frequency noise.

In summary, the decibel number of noise reduction by glass wool is not a fixed value. It will vary between 3 - 20 decibels, depending on many factors such as the density, thickness, installation method, location and type of noise of the glass wool.