What is the fire resistance limit of A1 grade glass wool in hours?

Manufacturing process and raw materials of glass wool

The exceptional fire resistance of A1-grade glass wool is inseparable from its raw materials and manufacturing process. Its main raw materials are primarily natural minerals such as quartz, which inherently possess excellent properties such as high-temperature resistance and high stability. During production, carefully selected raw materials are first placed in a high-temperature furnace and smelted at ultra-high temperatures until they become liquid. Subsequently, the liquid raw material is fed into a centrifuge, where the high-speed centrifugal force stretches the material into extremely fine inorganic fibers. After a series of subsequent processing steps, the A1-grade glass wool we see is finally formed. Throughout the process, parameters at each stage are strictly controlled to ensure that the produced glass wool has a uniform texture, long and fine fibers, and a dense structure, thus possessing excellent fire resistance, thermal insulation, sound absorption, and other superior properties, making it an indispensable functional material in the construction industry.

Factors affecting the fire resistance limit of A1 grade glass wool

density factor

Density is one of the key factors affecting the fire resistance limit of A1-grade glass wool. Generally speaking, a higher density means that there are more glass wool fibers per unit volume, and their arrangement is more compact. When the fibers are tightly packed, it improves thermal resistance because heat encounters more resistance during conduction, thus slowing down the heat transfer rate. This allows the glass wool to more effectively prevent the spread of heat when facing flames, thereby extending the fire resistance time. On the other hand, the stronger mutual support between the tightly packed fibers helps prevent fiber shedding or breakage, reducing the penetration of flames and decreasing the possibility of fire spreading through the glass wool. Moreover, high-density glass wool has a higher density, making it more difficult for flames to penetrate, which plays a crucial role in protecting the underlying building structure and other materials. However, it should be noted that while a higher density improves fire resistance, it also brings problems such as increased weight, increased construction difficulty, increased thermal conductivity, and increased cost. Therefore, in practical applications, the appropriate density of A1-grade glass wool should be selected based on a comprehensive consideration of the specific usage scenario and requirements.

Thickness factor

The thickness of glass wool is closely related to its fire resistance rating. Generally, the thicker the glass wool, the longer its fire resistance time. For example, ordinary centrifugal glass wool with a thickness of 5cm typically has a fire resistance rating of around 0.75 hours; while when the thickness reaches around 10cm, the fire resistance rating can reach 1 hour. In building applications, for glass wool used in exterior walls and roofs (such as attics), as long as it is tightly packed, the thicker the layer, the more effectively it can block fire, buying more time for evacuation and rescue in the event of a fire. Therefore, in places with high fire protection requirements, thicker A1-grade glass wool is often selected to improve the overall fire safety factor, depending on the actual needs.

Other factors

Besides density and thickness, other factors also affect the fire resistance limit of A1-grade glass wool. For example, the presence of a facing, such as FFR aluminum foil facing, further enhances the fire resistance of the glass wool, forming an additional fire barrier to prevent direct contact between flames and the glass wool, while also helping to reduce heat transfer. Differences in manufacturing processes are also significant. Advanced and refined manufacturing processes result in more uniform fiber density and a more stable structure in the glass wool, making it more reliable and resistant to flame attack when facing high temperatures. Furthermore, the quality of raw materials is crucial. High-quality raw materials possess better high-temperature resistance and stability, naturally leading to a higher fire resistance limit for A1-grade glass wool. When selecting A1-grade glass wool, all these factors need to be considered comprehensively to choose the product that best meets fire protection requirements.

Fire resistance performance of A1 grade glass wool in different scenarios

Architectural field

In the construction industry, A1-grade glass wool demonstrates superior fire resistance, safeguarding building safety. For example, in exterior wall insulation, as a non-combustible material, it will not burn even in the presence of a fire source, effectively preventing the spread of external fire to the building's interior. In high-rise buildings, the use of A1-grade glass wool significantly reduces the risk of fire propagating from the exterior walls to upper floors. Generally, when A1-grade glass wool of moderate thickness is used in exterior walls, it can maintain its structural stability for a considerable period during a fire, ensuring the structural safety behind the wall. Its fire resistance time can reach approximately 0.5 to 1 hour, depending on factors such as its thickness and density. In building roofs, especially in attics with flat or sloping roofs, A1-grade glass wool not only provides thermal insulation but also fire resistance in the event of a fire. For example, on the roofs of some industrial plants or warehouses, in the event of a fire below, glass wool can prevent the fire from spreading to adjacent buildings through the roof, buying more time for rescue and evacuation. Its fire resistance rating generally meets the initial isolation requirements of a fire, allowing people inside the building to escape. In building smoke control systems, A1-grade glass wool is indispensable. According to the "Technical Standard for Building Smoke Control Systems" GB51251, it meets the fire resistance and heat insulation requirements of smoke control systems, ensuring that smoke exhaust pipes can operate normally for a period of time during a fire, preventing high temperatures and flames from damaging the smoke exhaust system, ensuring that dense smoke can be discharged in a timely manner, and reducing the risk of people suffocating from inhaling toxic fumes. Its fire resistance rating can be maintained for approximately 0.5 to 1.5 hours under different working conditions, creating favorable conditions for fire rescue.

Industry, metallurgy and other fields

In industries like manufacturing and metallurgy, fire hazards are often more complex and severe. For example, industrial plants contain various electrical equipment and high-temperature production processes, all factors that can easily ignite a fire. A1-grade glass wool, with its non-combustible properties and excellent fire resistance, can be used to wrap and protect critical equipment and production lines within the plant. In the event of a localized fire, it can prevent the fire from spreading rapidly to other areas, avoiding greater damage. Its fire-resistant duration depends on the thickness and density of the glass wool in the actual application scenario, allowing firefighters valuable time to reach the scene and ensuring the safety of important facilities and materials within the plant. In the metallurgical industry, A1-grade glass wool can be used as a heat insulation and fireproofing material around high-temperature furnaces and metal smelting processes. It can withstand high-temperature environments and will not ignite even with sparks or high-temperature heat radiation. It maintains its integrity for a certain period, acting as an insulator to block heat and prevent the spread of fire, ensuring that surrounding workers and other production processes are not threatened by fire. Its fire resistance limit, depending on the actual installation, can effectively respond to sudden fire situations and protect the safety of the entire production environment.

Recommendations for the proper selection and use of Grade A1 glass wool

When selecting A1 grade glass wool, multiple factors need to be considered to ensure that it can meet the actual use scenario and perform its best fireproof and other related properties.

First, the choice should be based on fire safety requirements. For applications with extremely high fire safety standards, such as warehouses storing flammable and explosive materials or large, densely populated commercial centers, A1-grade glass wool with relatively high density and thickness should be selected. This will allow more time for rescue and evacuation in the event of a fire, and minimize the spread of fire. For ordinary factories and small office spaces with less stringent fire safety requirements, glass wool with appropriate density and thickness can be selected based on budget and other factors.

Secondly, budget is also an important consideration. Generally speaking, high-density, thick A1-grade glass wool is relatively expensive. If the budget is limited and fire safety is not a primary concern, it's advisable to compare the cost-effectiveness of different manufacturers and specifications to choose a glass wool that meets fire safety requirements while remaining relatively economical. Furthermore, the difficulty of installation should not be overlooked. For example, in areas with limited space and complex construction conditions, choosing glass wool that is relatively lightweight, easy to cut, and easy to install is more suitable. This avoids delays or poor installation results due to inconvenient construction, which could affect the subsequent fireproofing and insulation functions.

In summary, it is essential to weigh factors such as fire protection requirements, budget, and construction difficulty to select the most suitable A1 grade glass wool product.

Precautions

There are several points to consider when using A1-grade glass wool to ensure its fire resistance is fully realized. During installation, the glass wool must be tightly packed. For example, when filling exterior walls and roofs with glass wool, gaps should be minimized to prevent flames from spreading through them in the event of a fire, thus reducing its fire resistance. When laying glass wool boards, a staggered installation method can be used to reduce gaps between boards, creating a more tightly sealed fireproof and heat-insulating layer. At the same time, use in prolonged ultra-high temperature environments should be avoided. Although A1-grade glass wool itself has good high-temperature resistance and fire resistance, its structure and performance may be affected if it is exposed to temperatures far exceeding its tolerance limits for extended periods, such as continuously operating in areas above 400°C, thereby reducing its fire resistance. In such high-temperature conditions, more suitable methods such as double-layer insulation should be considered to ensure fire resistance and heat insulation effects. Furthermore, during transportation and storage, it is crucial to prevent glass wool from becoming damp or damaged. Moisture can affect its insulation and fire-resistant properties, while damaged glass wool compromises its structural integrity, hindering its fire-resistant performance. In short, only by paying attention to these details during use can the fire-resistant limit of A1-grade glass wool be achieved to its ideal state.