Which has better fire resistance, rock wool or glass wool?

Rock wool and glass wool are two common choices for building insulation materials. They excel not only in physical properties and sound insulation but also, and their differences in fire resistance are a key concern. This article will analyze the fire resistance of rock wool and glass wool from multiple perspectives to provide you with a reference when making your purchase.

 I. Introduction to Rock Wool and Glass Wool

Rock wool is an insulation material made from high-temperature molten rock (such as basalt and limestone) and then subjected to fiberization. In addition to its excellent thermal insulation properties, rock wool's chemical stability and fire resistance have led to its widespread use in the construction and industrial sectors.

Glass wool is made from molten glass at high temperatures and then fiberized to form a lightweight insulation material. Glass wool not only has excellent thermal and sound insulation properties, but it is also used in many construction applications, especially suitable for the insulation needs of residential and commercial buildings.

 II. Comparison of fire resistance performance

1. Refractory temperature

   Rock wool can withstand temperatures above 1000°C, and some specially treated rock wool can even withstand higher temperatures. This makes rock wool less prone to combustion in high-temperature environments and prevents its performance from deteriorating due to increased temperature.

   - Glass wool has a relatively low fire resistance temperature, with most products having a fire resistance rating of around 450°C. Although glass wool has some fire-resistant properties, its lower fire resistance limit may cause it to lose its protective effect in high-temperature environments.

2. Thermal conductivity

   Rock wool has a relatively low thermal conductivity, typically around 0.035 W/(m·K), which means it can effectively block heat conduction in high-temperature environments, thereby maintaining the stability of buildings.

   - Glass wool has a relatively high thermal conductivity, ranging from 0.040 W/(m·K) to 0.045 W/(m·K). This means that at high temperatures, glass wool may not provide as much protection as rock wool.

3. Combustion performance

   Rock wool exhibits superior combustion performance, belonging to non-combustible materials (Class A fireproof materials), and will not produce harmful gases when burning in a fire.

   While glass wool does offer some fire resistance, its composition contains organic components, classifying it as a combustible material (B1 fire-resistant). In a fire, glass wool may release harmful gases, impacting the environment and human safety.

 III. Application Case Analysis

1. Industrial buildings

   In industrial buildings, rock wool is widely used for insulation and fire protection due to the high temperatures and fire risks generated by equipment operation. For example, many petrochemical companies choose rock wool for the insulation layers of reactors and storage tanks to ensure equipment safety and efficiency.

   Glass wool is more often used in areas with lower fire risk, such as office partitions and equipment casing insulation. Although it provides good protection, its use in high-risk areas still requires caution.

2. Civil buildings

   Rock wool is widely used in the civil building industry, especially in high-fire-risk areas such as kitchens and equipment rooms. Many countries have strict requirements for the fire resistance of building materials, making rock wool a preferred material in many national building standards.

   - Glass wool is mainly used for thermal insulation and sound insulation of walls and roofs in civil buildings. Although its fire resistance is relatively weak, it still has a high cost performance and is suitable for building areas with less stringent fire protection requirements.

 IV. Summary

In conclusion, rock wool is clearly superior to glass wool in terms of fire resistance, especially in high-temperature and high-fire-risk environments. Its non-combustibility and higher fire resistance temperature make rock wool a better choice. Glass wool, on the other hand, also offers good thermal insulation and is economical in certain specific applications, making it suitable for situations with relatively low fire risk. When choosing insulation materials, users need to comprehensively consider factors such as actual needs, budget, and fire risk. Generally speaking, for projects requiring high fire resistance, rock wool is undoubtedly the more suitable choice. For situations with limited budgets or low fire risk, glass wool is also a good option.