Glass wool, as a mature thermal insulation and soundproofing material, is ubiquitous in construction, industrial equipment, and HVAC systems. Many people know that glass wool provides "thermal insulation, heat insulation, and sound absorption," but what truly determines its performance are its underlying "technical parameters." For engineering procurement, design institutes, and bidding technicians, a clear understanding of these parameters is crucial for accurate selection, reliable application, and the overall system's energy efficiency and safety.

I. The Density Parameter of Glass Wool Determines the Material's Basic Properties

The common density range for glass wool is 10–80 kg/m³.

Higher density means denser fibers, which alters the thermal conductivity, sound absorption coefficient, and compressive strength.

Low density (10–16 kg/m³) is often used for large-area installations, such as steel structure roof insulation;

Medium density (20–32 kg/m³) is used for duct wrapping and equipment insulation;

High density (above 48 kg/m³) is commonly used for exterior wall insulation and sound-absorbing walls.

Density is not necessarily better the higher it is; different scenarios require different strengths.

Glass Wool Board

II. Thermal Conductivity is the Core Indicator for Evaluating the Insulation Effect of Glass Wool

The typical thermal conductivity of glass wool is 0.033–0.042 W/(m·K).

The lower the value, the stronger its ability to block heat transfer.

Factors affecting thermal conductivity include:

1. Fiber diameter and uniformity

2. Internal porosity

3. Material moisture content

4. Operating temperature environment

For design institutes, specifying the thermal conductivity range when selecting materials is crucial, as it's the most direct basis for judging energy-saving effects.

Glass Wool Felt

III. Water Repellency Determines Long-Term Stability

Qualified glass wool generally has a water repellency rate ≥ 98%. Better water repellency means the material is less likely to absorb water, thus maintaining stable thermal conductivity and preventing structural layer dampness.

Water repellency is particularly important for HVAC ducts, roof insulation, and underground spaces.

IV. Combustion Performance Rating Affects Building Safety Level

Glass wool is a Class A non-combustible material with a fire resistance temperature exceeding 450℃.

This parameter is a mandatory requirement in scenarios such as exterior wall systems, high-rise buildings, power plants, and the petrochemical industry.

V. Sound Absorption Coefficient Affects Acoustic Performance

The NRC sound absorption coefficient of glass wool generally ranges from 0.75 to 1.05, varying depending on thickness and density.

In scenarios such as computer rooms, cinemas, schools, and rail transit station halls, this parameter directly affects the quality of the acoustic environment.

Acoustic Glass Wool

VI. Compressive Strength Relates to Construction and Long-Term Load-Bearing Capacity

The compressive strength of glass wool for different applications generally ranges from 5 to 35 kPa.

Roof profiled steel sheet insulation and central air conditioning duct wrapping require high compressive strength.

Understanding the technical parameters of glass wool means understanding the relationship between material properties and engineering performance. Whether used in building energy conservation, sound insulation systems, or HVAC equipment, glass wool can maintain long-term stable performance as long as the parameters are selected reasonably and the construction is carried out properly.