Is Fiberglass Flammable?

I may receive a commission if you make a purchase after clicking a link on this page. Read the full disclosure policy here

Fiberglass is one of the most widely used insulating materials in the world.

Besides being an insulating material that is most commonly used in the construction of homes, fiberglass is also used to help insulate a variety of other buildings due to its extremely affordable price.

Not only that, but besides being mega-affordable, fiberglass is also very easy to use and is pliable enough to fit into a variety of different spaces, including the most tricky.

Typically, fiberglass is used in between both exterior and interior walls and is used in order to prevent heat from radiating. 

Given all of its benefits, it means that fiberglass is one of the most popular choices for homeowners looking to keep their house nice and toasty warm.

But, despite its affordability – is there a chance that fiberglass could catch on fire if exposed and potentially put you and your home at risk?

In this article, we answer that question. Read on.

What Is Fiberglass, Exactly?

Before we go any further, we first think it would be a good idea to talk you through what fiberglass actually is.

In a nutshell, fiberglass is a kind of reinforced material that is made out of plastic and completed with a woven fabric across its surface.

After this manufacturing stage, the fiberglass is then usually finished with a resin mixture in order to make it super strong and durable.

In addition to this, due to its strength, affordability, and durability – it means that fiberglass is typically used to serve a variety of different purposes, including the following:

  • Housing construction: Fiberglass is commonly used during the construction of houses, including in the roofs, interior walls, as well as exterior walls, too.
  • Cars: Besides during house construction, fiberglass is a popular material that is used to help insulate car panels. 
  • Aviation: Less commonly, fiberglass is also occasionally used to help insulate aircraft.

Is Fiberglass Flammable?

Even though fiberglass is extremely durable and designed to last, it’s very important to keep in mind that fiberglass is flammable when exposed to very high temperatures.

To give you an idea of what type of temperature range fiberglass catches fire at, the average temperature is considered to be around 1000 degrees Fahrenheit.

However, despite the fact that fiberglass can catch on fire, it’s also important to note that fiberglass rarely does ignite, and will instead melt in most cases where it has been exposed to extremely high temperatures. 

Nevertheless, even though it takes extremely high temperatures to get fiberglass to actually go up in flames rather than melt, you will still need to be cautious of melting fiberglass, as it can give off fumes that can be dangerous to you and your family’s health, not to mention causing damage to its surroundings. 

Fiberglass

What Temperature Will Fiberglass Catch On Fire?

As we’ve already touched upon above, even though fiberglass won’t typically ignite when exposed to high temperatures, it will catch on fire under certain conditions.

Due to the fact that fiberglass is so fire-resistant, an accurate and precise burning temperature is hard to give.

However, there have been many different controlled tests carried out to determine an average temperature for burning fiberglass, and it is widely considered that the optimum temperature for burning fiberglass is around 1000-1200 degrees Fahrenheit. 

However, please do keep in mind that this is only an estimate of the type of temperature required to set fiberglass on fire.

Due to its fire-resistant properties, a variety of other conditions and factors can come into play to determine whether or not fiberglass will ignite when exposed to high temperatures, which is why we strongly recommend that you make sure to do your due diligence with the manufacturer that you purchased your fiberglass from.

To follow, regardless of what type of fiberglass you have, and even though different types of fiberglass can ignite at different temperatures – it’s highly likely that your fiberglass will melt rather than burn if it is exposed to temperatures that are far too high. 

Does That Mean That Fiberglass Insulation Is Flammable?

Yes and no. In theory, due to the way that fiberglass insulation is constructed, it is safe to assume that fiberglass, while not impossible, is highly unlikely to catch on fire if exposed to temperatures in the 1000 degrees Fahrenheit range.

Moreso, unlike standard fiberglass, fiberglass insulation will also not catch on fire or burn for long periods of time at moderately high temperatures, which is great for homeowners as it helps to ensure maximum safety.

It’s also important to keep in mind that fiberglass insulation is slightly different from fiberglass as it has been specifically designed to be able to withstand heat and be fire-resistant due to the fact that it is used in homes and other occupied areas.

Due to this reason, if fiberglass insulation happens to be exposed to extreme temperatures, it is far likely that it will simply melt as opposed to going up in flames.

Nevertheless, while this may be the case, it is still important to make sure that you are taking all the necessary safety precautions just in case – including making sure to not keep hot electrics or additional materials over the top of the fiberglass insulation.

In addition to this, if you’re ever unsure, we recommend that you make sure to check in with the manufacturers of your fiberglass, as they will be able to provide you with important safety information tailored to your particular brand and type of fiberglass.

Related:

About David

With over 12 years experience in the fire protection industry, David is our resident Safety & Security expert. He's also a plumber with years of experience in HVAC systems, welding extraordinaire and spends his weekends thinking up gardening projects.

Leave a Comment