Is Fiberglass Insulation Flammable? Discover the Truth

When it comes to insulating your home, there are many options. One popular choice is fiberglass insulation.

It’s known for its effectiveness in keeping homes warm in the winter and cool in the summer.

But what about its flammability? This is an important question that many homeowners have and one that we will explore in this article.

So please sit back, relax, and let’s dive into the world of fiberglass insulation and its potential fire hazards.

What Is Fiberglass Insulation?

Fiberglass insulation is a thermal insulation material widely used in residential, commercial, and industrial buildings.

It comprises extremely fine glass fibers bound together using a resin or polymer binder.

These fibers create a fluffy and lightweight material that effectively reduces heat transfer.

The manufacturing process for fiberglass insulation involves melting glass at high temperatures and spinning it into fine fibers.

These fibers are then assembled into mats or rolls, often with the addition of a facing material such as paper or foil for enhanced durability and moisture resistance.

Fiberglass insulation is commonly installed in the walls, ceilings, and attics of buildings to provide thermal insulation and improve energy efficiency.

It works by trapping air pockets within the fibers, slowing heat transfer through conduction and convection.

The advantages of fiberglass insulation include its affordability, versatility, and ease of installation.

It is available in various forms, including batts (pre-cut sections), rolls, and loose-fill, allowing a flexible application to suit different construction requirements.

Fiberglass insulation is also non-combustible and resistant to moisture, mold, and pests.

Is Fiberglass Insulation Flammable?

The short answer is that fiberglass insulation is not flammable. Fiberglass insulation is classified as a non-combustible material. This means that it will not catch fire or contribute to the spread of flames in the event of a fire.

Fiberglass insulation is made from tiny glass fibers woven together into a mat. These fibers are then coated with a fire-resistant material that helps to prevent the insulation from catching fire.

Fiberglass insulation is often treated with a fire retardant, enhancing its fire-resistant properties.

Despite its non-flammable nature, it is important to note that fiberglass insulation can still be damaged by fire.

The fibers can melt or break down if exposed to high temperatures, compromising the insulation’s effectiveness.

Is Fiberglass Insulation Flammable

In addition, fiberglass insulation can release toxic fumes when burned, harming both humans and animals.

At What Temp Does Fiberglass Catch Fire?

The exact temperature at which fiberglass catches fire depends on various factors, including the specific composition of the fiberglass material and any additional coatings or treatments it may have.

However, fiberglass is considered non-combustible and has a relatively high ignition temperature.

Generally, fiberglass will not catch fire until it reaches temperatures above 1,000 degrees Fahrenheit (537 degrees Celsius).

At these extreme temperatures, the resin or polymer binder that holds the glass fibers together may begin to break down and burn.

However, it is important to note that other components near fiberglass, such as adhesives, paints, or combustible materials, may ignite at lower temperatures and contribute to spreading fire.

Is Fiberglass Explosive?

No, fiberglass itself is not explosive. Fiberglass is a composite material made of fine glass fibers embedded in a resin or polymer matrix.

Neither the glass fibers nor the resin used in fiberglass possesses explosive properties.

Explosive materials typically undergo rapid combustion or decomposition, releasing a large amount of energy in a short time frame.

This is not the case with fiberglass. While fiberglass is not explosive, it is essential to note that other flammable or explosive materials, such as fuels, gases, or chemicals, may be present in the vicinity of fiberglass, especially in specific applications like boats or vehicles.

Is Fiberglass Toxic

The answer is not straightforward, as it depends on several factors.

Firstly, the fibers themselves can be hazardous if inhaled. Tiny particles can be released into the air when fiberglass is cut or disturbed.

These particles, known as “fiberglass dust,” can then be inhaled into the lungs and cause irritation, coughing, and other respiratory problems.

Inhaling large amounts of fiberglass dust over long periods has also been linked to lung cancer.

Secondly, the chemicals used in producing fiberglass can also be toxic. Some fiberglass products use formaldehyde, a known carcinogen that can irritate the eyes, nose, and throat.

Other chemicals, such as styrene, can cause skin irritation and neurological problems if workers are exposed to them over extended periods.

However, it is worth noting that not all fiberglass products are created equal. Some fiberglass insulation, for example, is made without using formaldehyde or other harmful chemicals.

Proper safety precautions can also greatly reduce the risk of exposure to fiberglass dust and other hazardous materials.

Fiberglass Hazards

While fiberglass is a widely used material with numerous benefits, it is important to be aware of potential hazards associated with its handling and use. Here are some common fiberglass hazards:

Skin and Eye Irritation: Direct contact with fiberglass can cause skin irritation, redness, itching, and sometimes allergic reactions.

Fine glass fibers can also irritate the eyes, leading to redness, itching, and discomfort.

To minimize these risks, wearing appropriate protective clothing, such as long sleeves, gloves, and safety goggles, is important when working with fiberglass.

Respiratory Issues: Inhalation of airborne fiberglass particles can irritate the respiratory system and lead to respiratory discomfort, coughing, and wheezing.

Prolonged or repeated exposure to fiberglass dust may pose a risk of developing respiratory conditions such as bronchitis or fibrosis.

When working with fiberglass, wearing a properly fitted mask or respirator approved for fiberglass particulate is crucial to protect the lungs.

Fiberglass Splinters: Fiberglass can break or splinter, creating sharp edges or fragments that can cause physical injuries.

Handling fiberglass with bare hands or without appropriate protective equipment can result in cuts or punctures.

Wearing gloves and taking care when working with fiberglass can help minimize the risk of splinters.

Dust and Airborne Particles: Cutting, sanding, or grinding fiberglass can generate fine dust and airborne particles. Inhaling these particles can pose health risks.

It is important to use appropriate dust control measures, such as wet methods or dust collection systems, and work in well-ventilated areas to minimize exposure to airborne fiberglass particles.

Chemical Exposure: Some fiberglass products, such as resins, binders, or coatings, may contain chemicals that can pose hazards.

It is important to read and follow the manufacturer’s safety guidelines, including proper storage, handling, and disposal of fiberglass-related chemicals.

Types Of Insulation

There are several types of insulation commonly used in buildings and construction. Here are some of the main types of insulation:

Fiberglass Insulation: Fiberglass insulation is made of fine glass fibers bound together. It is available in batts, rolls, or loose-fill form.

Fiberglass insulation is commonly used in walls, ceilings, and attics to provide thermal insulation.

Foam Insulation: Foam insulation is available in two main types: spray and rigid.

Spray foam insulation is applied as a liquid that expands and hardens into a solid foam, providing excellent air sealing and insulation.

Rigid foam insulation comes in pre-cut panels and offers high-insulating properties.

Cellulose Insulation: Cellulose insulation is made from recycled paper products and treated with fire-retardant chemicals. It is often used as loose-fill insulation, blown into attics or wall cavities, and provides good thermal and sound insulation.

Mineral Wool Insulation: Mineral wool insulation is made from natural or synthetic minerals like rock or slag wool. It is available in batts or loose-fill form.

Mineral wool insulation provides excellent fire resistance and sound insulation properties.

Reflective Insulation: Reflective insulation consists of a layer of aluminum foil or film that reflects radiant heat. It is commonly used in attics, walls, and roofs to reduce heat transfer by reflecting heat away from the living spaces.

Radiant Barrier: A radiant barrier is similar to reflective insulation, but it is typically a thin, reflective material installed on the underside of roofs or in attic spaces. It helps reflect radiant heat away from the building, reducing cooling costs.

Polystyrene Insulation: Polystyrene insulation comes in two main forms: expanded polystyrene (EPS) and extruded polystyrene (XPS).

EPS is available as rigid foam panels or beads, while XPS is a dense foam board. Both types provide good thermal insulation.

Polyurethane Insulation: Polyurethane insulation is a foam insulation offering excellent thermal insulation and air-sealing properties. It is commonly used in spray foam form to fill gaps and cavities.

Is Fiberglass And Pink Insulation The Same

In terms of their composition, yes. Both types of insulation are made from tiny glass fibers woven together.

However, pink insulation is a fiberglass insulation made by Owens Corning. There are other brands of fiberglass insulation available that may not be pink in color.

One potential advantage of pink insulation is that it’s often available in pre-cut batts or rolls, making installation easier.

However, other brands of fiberglass insulation are also available in pre-cut sizes.

Regarding performance, both fiberglass and pink insulation effectively regulate temperature and reduce sound transmission.

The R-value of the insulation is a crucial factor in determining its effectiveness. Higher R-values provide better thermal resistance, which can help reduce energy costs and improve indoor comfort.

In terms of cost, fiberglass insulation is generally an affordable option. The cost of pink insulation may be slightly higher as it is a branded product.

However, the cost difference is typically minimal.

Difference between Fiberglass Insulation And Foam Insulation

Fiberglass and foam insulation are two commonly used insulation materials with distinct characteristics. Here are the critical differences between fiberglass insulation and foam insulation:

Composition: Fiberglass insulation comprises fine glass fibers bound together, while foam insulation comprises various plastic or polymer materials.

Fiberglass insulation has a fibrous structure, whereas foam insulation is more solid and has a cellular structure.

Installation: Fiberglass insulation is typically available in batts (pre-cut sections) or rolls, making it easy to install between wall studs, ceiling joists, or attic spaces.

It requires cutting and fitting to the desired size. Foam insulation, on the other hand, is typically installed as a spray or rigid board.

Spray foam is applied as a liquid that expands and hardens into a solid foam, while rigid foam comes in pre-cut panels.

Insulation Performance: Both fiberglass and foam insulation provides thermal insulation to reduce heat transfer.

However, foam insulation generally has higher insulating properties and can provide better air sealing due to its ability to fill gaps and cracks effectively.

Foam insulation also has a higher R-value (a measure of thermal resistance) per inch compared to fiberglass, which offers better insulation per unit thickness.

Moisture Resistance: Fiberglass insulation is not affected by moisture and does not absorb water, making it resistant to mold growth.

Foam insulation, especially closed-cell spray foam, has better moisture resistance and can act as a vapor barrier when properly installed, providing an added layer of protection against moisture intrusion.

Air Sealing: Foam insulation has excellent air-sealing properties due to its ability to expand and conform to irregular surfaces, sealing gaps and cracks effectively.

Fiberglass insulation, while it can reduce heat transfer, is not as effective at air sealing because it is more challenging to fit tightly around obstacles or fill small gaps.

Cost: Fiberglass insulation is generally more affordable than foam insulation, especially considering the material and installation costs.

Foam insulation, mainly spray foam, tends to have higher upfront costs but can provide long-term energy savings due to its superior insulation and air-sealing properties.

Does Fiberglass Burn Or Melt?

The short answer is that fiberglass does not burn but can melt under certain conditions. Let’s look at what happens when fiberglass is exposed to heat.

First, it’s important to understand that fiberglass is made of tiny glass fibers woven together to form a cloth-like material.

These fibers are highly resistant to heat and do not ignite easily.

Fiberglass has a high ignition temperature of around 650°C (1202°F), much higher than most other materials.

However, if fiberglass is exposed to extremely high temperatures, it can begin to melt.

This is because the glass fibers in the material soften and begin to flow, similar to how ice melts when exposed to heat.

The temperature at which fiberglass begins to melt depends on the type of fiberglass and the specific application it is used for.

For example, insulation fiberglass typically has a melting point of around 1000°C (1832°F), while fiberglass used in boat hulls may begin to melt at lower temperatures.

What Insulation Is Most Flammable?

Among common insulation materials, some types are more flammable than others. Here are a few examples of insulation materials that are generally considered more flammable:

Cellulose Insulation: Cellulose insulation, made from recycled paper products, can be more flammable than other types of insulation. However, it is treated with fire-retardant chemicals to improve its fire resistance.

Spray Foam Insulation: While spray foam insulation provides excellent thermal insulation and air-sealing properties, some formulations can be more flammable.

However, there are fire-resistant versions of spray foam insulation available that have been specifically designed to reduce flammability.

Polystyrene Insulation: Both expanded polystyrene (EPS) and extruded polystyrene (XPS) insulation can be flammable. However, manufacturers typically add flame retardants to improve their fire resistance.

Insulation Fire Rating Chart

The fire rating of insulation materials is typically determined by standardized tests that assess their performance in fire conditions.

The fire rating indicates the degree of fire resistance and the ability of the insulation material to limit the spread of flames and smoke.

It is important to note that fire ratings can vary depending on the specific product and manufacturer. Here is a general overview of standard fire ratings for insulation materials:

Quick Overview of Problems And Solutions

Insulation Type
Fire Rating
Fiberglass Insulation
Class A or Class B
Foam Insulation
Class A or Class B
Cellulose Insulation
Class A or Class B
Mineral Wool Insulation
Class A or Class B
Reflective Insulation
Class A or Class B
Radiant Barrier
Class A or Class B
Polystyrene Insulation
Class A or Class B
Polyurethane Insulation
Class A or Class B

Safety Precautions For Fiberglass Insulation

When working with fiberglass insulation, taking appropriate safety precautions to protect yourself and minimize potential health risks is essential. Here are some safety precautions to consider:

Personal Protective Equipment (PPE): Wear the following PPE to protect your skin, eyes, and respiratory system:

Long-sleeved clothing and long pants to minimize skin exposure.

Gloves are made of a material that provides adequate protection against fiberglass fibers, such as nitrile or work gloves.

Safety goggles or glasses to protect your eyes from fiberglass particles.

A dust mask or respirator is specifically designed for fiberglass insulation to prevent inhalation of airborne particles.

Choose a mask with a rating suitable for the size of the fiberglass particles you are working with.

Proper Ventilation: Ensure adequate ventilation in the area where fiberglass insulation is installed.

Open windows and doors or use fans to improve air circulation and minimize the concentration of airborne particles.

Minimize Dust: Take steps to reduce the generation and spread of dust:

Avoid unnecessary cutting, sanding, or disturbing fiberglass insulation, as it can release more particles into the air.

Use the appropriate cutting tools to minimize the production of fine dust.

Wetting the insulation before cutting or handling it can help reduce dust.

Safe Handling and Installation: Follow the manufacturer’s guidelines and instructions for the specific fiberglass insulation product.

Avoid direct contact with exposed skin. If contact occurs, gently rinse the affected area with water.

Handle insulation material carefully to prevent breakage or splintering.

Do not eat, drink, or smoke while working with fiberglass insulation.

Clean tools and work areas properly after insulation work to remove dust or debris.

Hygiene Practices: Wash your hands thoroughly with soap and water after handling fiberglass insulation.

Launder work clothes separately from other clothing items to minimize the spread of fiberglass particles.

If you experience any symptoms of skin irritation, respiratory discomfort, or other health issues after working with fiberglass insulation, seek medical attention promptly.


Fiberglass insulation is considered to be relatively fire-resistant. While fiberglass is not flammable, it can melt or degrade when exposed to high temperatures.

However, fiberglass insulation is typically treated with fire-retardant additives during manufacturing to enhance its fire resistance.

These additives help delay ignition and slow down the spread of flames. While fiberglass insulation is not completely fireproof, when properly installed and combined with appropriate fire safety measures, it can provide effective thermal insulation while reducing the risk of fire hazards.