Glass wool is a high-efficiency insulation material widely used in construction, HVAC, and industrial insulation. Its density is one of the important factors affecting its insulation, sound absorption, and fire resistance properties. So, how does the density of glass wool affect its performance? This article will analyze the role of glass wool density in terms of insulation performance, sound absorption performance, and fire resistance performance.

I. What is the Density of Glass Wool?

The density of glass wool, commonly known as its volume, refers to the mass of glass wool per unit volume, usually expressed in kg/m³. Density is an important indicator of the relationship between the mass and volume of a material, directly affecting its physical properties.

During the production process of glass wool, the density can be adjusted according to usage requirements. The common density range is approximately 30–200 kg/m³.

II. The Influence of Glass Wool Density on Performance

1️⃣ Relationship between Thermal Insulation Performance and Density

Thermal insulation performance is one of the most important properties of glass wool, and density directly affects it:

Low Density Glass Wool:

Contains more air pores, as air has lower thermal conductivity.

Low density glass wool typically has a lower thermal conductivity, resulting in better thermal insulation performance.

Suitable for low-temperature applications or environments with high heat loss control requirements.

High Density Glass Wool:

Fewer pores and a higher proportion of solid skeleton, leading to more heat conduction paths.

Slightly higher thermal conductivity, resulting in slightly lower thermal insulation performance.

More suitable for applications requiring higher mechanical strength, such as external insulation of industrial equipment or environments subject to high pressure.

Conclusion: Low density glass wool exhibits superior thermal insulation performance and is suitable for low-temperature applications or applications with high energy-saving requirements. While high density glass wool has slightly weaker thermal insulation performance, it is more suitable for environments requiring heavy loads or high mechanical strength.

2️⃣ Relationship between Sound Absorption Performance and Bulk Density

The sound absorption performance of glass wool is generally related to its pore structure, which in turn is directly related to its bulk density.

Low Bulk Density Glass Wool:

Higher porosity, effectively absorbing sound waves, with better absorption of high-frequency noise.

Suitable for places with high noise control requirements, such as conference rooms, computer rooms, and cinemas.

High Bulk Density Glass Wool:

Fewer pores, poorer airflow, and slightly inferior sound absorption.

Mainly used for controlling low-to-mid frequency noise, such as in equipment rooms and industrial plants.

Conclusion: Low bulk density glass wool performs better in sound absorption and noise reduction, especially for high-frequency noise. High bulk density glass wool performs better in absorbing low-to-mid frequency noise, but its overall sound absorption effect is slightly weaker.

3️⃣ Relationship between Fire Resistance and Bulk Density

Glass wool itself is made of inorganic materials and has excellent fire resistance; bulk density has a relatively small impact on its fire resistance performance.

Low-density glass wool:

While it offers good thermal insulation at high temperatures, its higher porosity may affect its fire resistance, especially at extremely high temperatures where heat convection in the air may slightly increase.

High-density glass wool:

It is more stable and may have slightly better fire resistance due to its fewer internal pores, resulting in shorter heat conduction paths within the material.

Suitable for applications requiring high fire ratings, such as firewalls, roofs, and industrial facilities.

Conclusion: The fire resistance of glass wool is less affected by its density, but high-density glass wool may have a slight advantage in applications requiring high fire resistance.

III. The Influence of Glass Wool Density on Mechanical Properties

Besides thermal and acoustic properties, the density of glass wool also affects its mechanical strength.

Low-density glass wool:

While it offers good thermal insulation and sound absorption, its looser structure results in lower compressive strength and makes it easily compressible.

Suitable for applications with lower load-bearing requirements, such as interior wall insulation and air conditioning duct insulation.

High-density glass wool:

It possesses strong compressive strength and impact resistance, making it suitable for environments requiring high pressure resistance, such as external equipment insulation and high-temperature pipelines.

Conclusion: High-density glass wool has higher mechanical strength and is suitable for high-pressure, high-impact environments, while low-density glass wool is more suitable for general insulation and sound absorption applications.

IV. Glass Wool Density Selection Recommendations

Select the appropriate glass wool density based on application requirements:

Low density (30–60 kg/m³): Suitable for environments with high requirements for low-temperature insulation and sound absorption/noise reduction.

Medium density (60–100 kg/m³): Suitable for general insulation, equipment insulation, and pipeline insulation.

High density (100–200 kg/m³): Suitable for industrial equipment and environments requiring higher mechanical strength.

The density of glass wool directly affects its insulation performance, sound absorption effect, fire resistance, and mechanical strength. Low-density glass wool offers excellent thermal insulation and sound absorption properties, making it suitable for low-temperature insulation and noise control applications. High-density glass wool, on the other hand, provides better mechanical strength and compressive strength, making it suitable for applications requiring high pressure or high-temperature environments. Selecting the appropriate density of glass wool based on specific engineering needs will maximize its performance advantages.