According to the North American Insulation Manufacturers Association (NAIMA), fiberglass insulation is non-combustible and does not contribute to fire spread. Composed of tiny glass fibers, it can withstand high temperatures without burning, making it a popular choice for enhancing fire safety in homes.
However, concerns arise when additives like vapor barriers or paper facings are used, which may affect its overall fire resistance.
But Generally, Is fiberglass insulation flammable? In one liner, No, the fiberglass insulation is generally considered non-flammable and is classified as a fire-resistant material.
However, understanding the flammability of insulation materials is crucial for homeowners aiming to improve fire safety while enhancing energy efficiency. Let’s proceed to see what makes fiberglass fire-resistant, common myths and its comparison with other materials
Is Fiberglass Insulation Fireproof: Fire Resistance of Common Insulation Materials
Composed of glass fibers, Fiberglass is inherently non-flammable. In the table below flame Spread Index (FSI) shows the rates how quickly flames spread across the material’s surface. A lower number indicates slower flame spread. Similarly, High-Temperature Performance indicates how the material behaves when exposed to high temperatures or direct flame.
| Insulation Material | Flammability | Fire Resistance | Flame Spread Index | High-Temperature Performance |
|---|---|---|---|---|
| Fiberglass Insulation | Non-flammable | Does not burn but melts at ~1,000°F (540°C) | 0 (Very Low) | Forms molten fiberglass without igniting |
| Mineral Wool (Rock Wool) | Non-flammable | Excellent; withstands up to ~2,150°F (1,177°C) | 0 (Very Low) | Retains structural integrity |
| Cellulose Insulation | Treated to be fire-resistant | Chars and slows fire spread due to fire retardants | 0-25 (Low) | May smolder but resists open flame |
| Spray Foam Insulation | Flammable | Ignites and burns; requires thermal barrier | 75+ (High) | Burns and produces toxic smoke |
| Foam Board Insulation | Flammable | Ignites at lower temperatures; combustible | 75+ (High) | Burns readily, emits toxic gases |
Understanding Fiberglass Insulation and its Composition
Melting glass and spinning it into extremely fine glass fibers/strands, it forms a fibrous material that traps air pockets. This structure reduces heat loss by limiting thermal conduction and convection.
Composition and Properties of Glass Fibers
The glass fibers in fiberglass insulation are made from sand and recycled glass, melted at high temperatures and extruded into thin strands. These fibers are non-combustible, meaning they do not ignite or support flame spread.
The material has a low flame spread index, enhancing its fire-resistant properties. Fiberglass can withstand high temperatures up to 1,000°F (540°C) before it begins to melt into molten fiberglass, but it does not burn. This property is crucial for maintaining fire safety in buildings.
How Fiberglass Insulation Works to Prevent Heat Loss
The effectiveness depends on the insulation thickness and proper installation. Thicker insulation provides a higher R-value, indicating better thermal resistance. In addition to thermal benefits, fiberglass also contributes to fire safety.
Its non-flammable nature ensures it does not contribute to the spread of house fires. A study by the National Research Council of Canada confirms that fiberglass insulation does not increase fire risk in residential buildings.
Is Fiberglass Insulation Flammable? Understanding Fire Resistance and Flame Spread Index
Again, fiberglass insulation is generally considered non-flammable, as it is composed of tiny glass fibers that do not ignite. At extremely high temperatures, typically above 1,000°F (540°C), fiberglass may melt into molten fiberglass, but it does not burn or support combustion.
Fire Resistance and Flame Spread Index
Fiberglass insulation has a Flame Spread Index (FSI) of 0, indicating minimal flame spread according to ASTM E84 testing standards. This low FSI means that fiberglass does not aid in the propagation of flames during a fire.
Its non-flammable nature contributes significantly to fire safety, ensuring that it does not exacerbate fire conditions in the event of an emergency.
Comparison with Other Insulation Materials
Compared to other insulation materials, fiberglass stands out for its non-flammable properties:
- Cellulose Insulation: Made from recycled paper (cellulose acetate) treated with fire retardants like boric acid. While it is treated to be fire-resistant, cellulose can smolder and potentially pose a fire hazard if the fire retardants degrade over time or if exposed to moisture.
- Mineral Wool (Rock Wool): Composed of natural or synthetic minerals, mineral wool is also non-flammable and offers exceptional fire resistance. It can withstand temperatures up to 2,150°F (1,177°C), making it suitable for applications requiring high levels of fire safety.
- Spray Foam Insulation: Includes types of foam insulation like polyurethane foam, which are flammable and can contribute to fire spread if not properly protected. Spray foam must be covered with a thermal barrier, such as drywall, to meet fire safety codes and prevent ignition
| Insulation Material | Flame Spread Index (FSI) | Melting/Ignition Temperature | Properties |
|---|---|---|---|
| Fiberglass Insulation | 0 – 25 (Class A) | Melts at ~1,000°F (540°C) |
– Non-flammable – Does not ignite but melts under extreme heat – Enhances fire safety |
| Mineral Wool (Rock Wool) | 0 – 25 (Class A) | Melts at ~2,150°F (1,177°C) |
– Highly fire-resistant – Maintains integrity at high temperatures – Ideal for fire safety applications |
| Cellulose Insulation | 0 – 25 (with fire retardant) | Ignites at ~450°F (232°C) |
– Made from recycled paper – Treated with fire retardants like boric acid – Can smolder if exposed to flame |
| Spray Foam Insulation | 75+ (Class B/C) | Ignites at ~700°F (371°C) |
– Flammable – Must be covered with a thermal barrier – Can contribute to fire spread |
| Foam Board Insulation (EPS/XPS) | 75+ (Class B/C) | Ignites at ~600°F (316°C) |
– Combustible – Produces toxic smoke when burning – Requires a vapor barrier for safety |
Does Fiberglass Melt? Role of Fiberglass Insulation in House Fires
Unlike combustible insulation materials, fiberglass has a low thermal conductivity and high melting point, beginning to melt into molten fiberglass only at temperatures around 1,000°F (540°C).
A study by the National Institute of Standards and Technology (NIST) confirms that fiberglass insulation can enhance structural fire endurance due to its fire-resistant insulation properties.
In a house fire, the performance of fiberglass insulation is crucial for delaying heat transfer and providing additional escape time. This melting absorbs heat energy, slowing down fire spread without releasing toxic fumes or contributing to the fire hazard.
Fire Safety Measures with Fiberglass Insulation
- Integration with Fire-Resistant Assemblies: Using fiberglass insulation in conjunction with mineral wool can improve overall fire resistance. Mineral wool withstands high temperatures up to 2,150°F (1,177°C), providing an extra layer of protection in critical areas like furnace rooms.
- Electrical Wiring and Pipe Insulation: Properly insulating around electrical wiring and using appropriate pipe insulation reduces the risk of ignition sources coming into contact with combustible materials. Ensuring that glass fibers do not obstruct ventilation helps prevent overheating.
- Use of Fire Retardants and Vapor Barriers: While fiberglass is inherently non-flammable, incorporating fire retardants in adjacent materials, like cellulose insulation, enhances overall fire safety. Installing a vapor barrier prevents moisture accumulation, which can lead to decay and compromise insulation effectiveness.
- Optimizing Insulation Thickness: Maintaining the recommended insulation thickness ensures maximum energy efficiency while adhering to safety standards. Over-insulating can trap heat and moisture, potentially increasing fire hazards.
Technical Recommendations for Homeowners
- Regular Inspection and Maintenance: Periodically check insulation for signs of damage or moisture intrusion. Replace compromised insulation to maintain both fire resistance and thermal performance.
- Compliance with Building Codes: Adhere to local building regulations, such as the International Residential Code (IRC), which specify requirements for flame spread index and the use of fire-resistant insulation materials.
- Professional Installation: Engage certified professionals insulation installing or upgrading Insulation. They can identify the best combination of insulation materials and ensure that installation does not inadvertently create fire hazards.
Frequently Asked Questions
Is it illegal to burn fiberglass insulation?
Yes, burning fiberglass insulation is generally illegal due to environmental regulations, as it releases toxic substances; always dispose of it according to local laws and guidelines.
Is burning fiberglass insulation toxic?
Yes, burning fiberglass insulation releases toxic fumes and glass fibers that are hazardous to inhale, posing serious health risks and compromising fire safety.
Does fiberglass burn or melt?
Fiberglass insulation does not burn but begins to melt into molten fiberglass at high temperatures around 1,000°F (540°C), without igniting or supporting flames.
Is fiberglass fire resistant?
Yes, fiberglass insulation is considered fire-resistant insulation because it is non-flammable and does not contribute to fire spread during house fires.
Is pink insulation flammable?
No, pink insulation, which is typically fiberglass insulation, is non-flammable and enhances fire safety by resisting ignition and flame spread.
