Fiberglass is a material also referred to as GRP (glass reinforced plastic). It is made by embedding small, superfine glass filaments (fibers) inside a woven mesh in a random fashion. This is then covered in a resin to bind all of the components together.
This is then either flattened into a strand mat (a thin, flat sheet) or is woven into a fabric. For some applications, additional ingredients may be added to give the material extra properties.
Fiberglass is an incredibly strong and hard-wearing material. It can be bought as a raw material or used to create molded objects through hot press manufacturing or pultrusion.
It is sometimes preferred to carbon fiber as it is lightweight, cheap, and flexible. There is no compromise on the strength of the material and it is UV and corrosion-resistant.
There are hundreds of uses for fiberglass. Some common ones include water tanks, shower trays, flat roofs, car body panels, luggage racks, fiberglass boats, circuit boards, and playground equipment to name a few.
How is fiberglass insulation made?
Fiberglass is made from silica sand combined with soda ash and limestone. The sand forms the basis of the glass element, and the other ingredients are used to drop the melting temperature, making it easier to manufacture.
There are some other ingredients added too. These include borax, feldspar, kaolin clay, and magnesite to improve the overall quality and performance of the fiberglass. These are combined well and then heated.
The mixture must reach a temperature that is higher than glass. This is approximately 2,500 degrees Fahrenheit and forces the ingredients to melt and combine. Once it has reached a molten state, the fiberglass is formed into its final state. This is fibers, filaments, or glass wool.
Once the fiberglass has been shaped, other coatings are applied to the material. Commonly used ones are anti-static agents and lubricants to reduce the abrasion of the fiberglass.
What does flammable mean?
If something is flammable, this means that it can catch fire and burn. Strangely, the word inflammable holds the same meaning. Flammable objects are likely to burn fairly quickly and can be dangerous around open flames.
What does fire-resistant mean?
An object that is fire-resistant can withstand the effects of fire and open flames for a specified time period. It is also designed to withstand a certain temperature level without structural damage or failures being incurred.
Fire-resistant objects do not allow for the transfer of heat and limit the upper temperature that the material can reach.
Is fiberglass flammable?
No, fiberglass is not flammable. It has been designed specifically to not catch fire which is why it has such a multitude of safe uses.
Pre-cut sections of insulation in the form of a blanket are known as batts. This is the kind of insulation that you would use on unfinished walls, ceilings, and floors. These batts often have brown paper added to function as a vapor barrier.
This is flammable. Sometimes manufacturers will add flame retardant adhesives and foils to the insulation.
Is fiberglass fire resistant?
Yes, fiberglass has been formulated specifically to be fire-resistant. The material has been known to withstand temperatures reaching up to 1,000 degrees Fahrenheit, or 540 degrees Celsius.
This is around the temperature of molten red lava. After this temperature is reached, the fiberglass will begin to melt.
A standard house fire can reach temperatures of up to 1,500 degrees Fahrenheit (815 degrees Celsius). This means that any fiberglass could begin to melt, and may act as an additional fuel source for the fire.
There are many very real health risks associated with melting fiberglass. The most obvious is that you will incur severe burns. The most common burns seen in house fires are 5th and 6th degree burns.
A 5th degree burn is where all of your skin and most of the muscle and ligaments have been burnt off. You will likely also notice charred areas of bone where the tissue is damaged.
A 6th degree burn is similar but with worse impacts and often results in loss of function of the burned area.
These are much worse than the burns you would encounter as a result of the flame. This is because the melting fiberglass can adhere to your skin, causing deeper and more lasting damage.
What temperature will fiberglass ignite at?
There have been many tests done on the ignition temperature of fiberglass. In a controlled environment, it has been shown to ignite at around 1,112 degrees Fahrenheit.
There are many different types of fiberglass, each having undergone different manufacturing processes. This means that there is likely to be some degree of variance in the temperature at which your fiberglass will ignite.
No matter the specific temperature your fiberglass will catch fire at, it is safe to assume that through normal use it will not set alight.
What about fiberglass resin?
This is a material that contains both epoxy and polyester resins within the construction. These are both flammable substances so you may be concerned about the safety of using them.
Once the resin has been set, your fiberglass material is not likely to catch fire. If in doubt, we recommend checking the safety sheet that was supplied along with the fiberglass.
What are the dangers of melting fiberglass?
Aside from the obvious issue of the fiberglass reaching high temperatures and spreading, there are some other problems. As the fiberglass spreads it will begin to conduct the heat towards other materials and objects within your home which are likely to be able to catch fire.
As the fiberglass material melts, the oxygen contained within the material will escape. Oxygen is very flammable and will feed the flames.
This means that if your fiberglass insulation in a cavity wall catches fire, the oxygen released will make the cavity become somewhat of a convection chamber and speed up the progression of the fire.
Is fiberglass a safe insulation to use?
Yes, it is a relatively safe form of insulation. Many people believe that it is safer than using cellulose but this is not the case. Cellulose insulation is made from recycled and shredded newspapers that have been treated with boric acid to make the material more fire retardant.
Cellulose insulation has a number of additional benefits including fighting mold, pests, and wood decay. This kind of insulation is much denser and there are far fewer air pockets.
This means that the spread of a fire through a cavity wall insulated with cellulose will be much slower than with fiberglass insulation.
Tests conducted by the Houle Insulation, Inc proved this point. Fires were set in walls insulated with fiberglass and cellulose insulation respectively.
The ceiling of the building with fiberglass insulation collapsed after 20 minutes. Under the same conditions, the ceiling of the building with cellulose insulation remained up for 70 minutes.
Cellulose insulation has also outperformed fiberglass insulation in many other areas. Less heat is lost to the environment overnight, suggesting its superior insulation properties.
This material is also more effective at insulating homes where the atmospheric temperature is lower. This is because the air pockets found in fiberglass insulation allow heat to escape.