Is Expanded Polystyrene Flammable? 

This article will answer the question, “is expanded polystyrene flammable?” It also covers several topics about expanded polystyrene, its properties, and how to respond to fire ignition caused by expanded polystyrene.

Is Expanded Polystyrene Flammable?

Yes. Expanded polystyrene is flammable. Because of its high combustibility, polystyrene must always be kept properly in any assembly. Expanded polystyrene foam (EPS) is a combustible organic substance. A substance’s ability to burn depends on elements such as its environment and its intrinsic properties. When installed correctly, expanded polystyrene products pose no fire hazard.

What Is Expanded Polystyrene?

Thermoplastic foam material known as expanded polystyrene, often known as EPS, is produced from solid polystyrene beads. 

To manufacture EPS, polystyrene plastic is mixed with a foaming ingredient, primarily pentane, and subsequently through a heating process.

When producing this foam material, the expansion exists due to a small amount of gas that becomes trapped in the polystyrene beads during the manufacturing process. 

During this heating procedure, an EPS with closed cells is formed. 

The heated foaming ingredient will then evaporate, making the polystyrene expand 20-50 greater than its initial size.

After that, the plastic is held for 6-12 hours to attain optimal shape and molded into various forms according to application needs.

Air makes up around 98 percent of expanded polystyrene. Because of this, it is one of the lightest materials used for packing. This helps to keep the costs of transportation to a minimum. 

This polymeric material has several desirable qualities, including excellent thermal insulation, damping capabilities, and lightweight. 

Because of its ability, it can be utilized in various contexts, including as a construction material, as a material for packaging, as a model airplane, etc. 

There are a few downsides, when utilizing ESP. For instance, it is not resistant to organic solvents. It can catch fire if painted with oil, and it might cause health problems if used as a material for packaging food products.

What Are the Properties of Expanded Polystyrene?

Thermal Characteristics

EPS plastic has a very low thermal conductivity since it is 98 percent air. The trapped air inside an EPS cell makes it a poor conductor of heat, giving good thermal insulation properties.

Mechanical Characteristics

EPS plastic has good pressure resistance; hence it is suited to be utilized as a cushion material for large loads.

Dimensional Stability

EPS has exceptional dimensional stability. Thus, it can hold its shape even under pressure.


EPS is not a hygroscopic substance; hence it tends to be water-resistant and moisture-resistant.

What are the Applications of Expanded Polystyrene?

Building & Construction

EPS is widely utilized in the building and construction industry due to its insulating characteristics and resistance to bacteria and other microbes. 

Its tight cell structure also makes EPS moisture resistant. Because of this, EPS products are long-lasting, robust, and suitable for use as panel systems for building walls, roofs, and floors.

Food Packaging

Extruded EPS can be formed into sheets, which can then be repurposed for use in a variety of applications, including the packaging of fresh food. In addition, because EPS plastic does not contain any nutrients, it does not support the growth of mold, bacteria, or other types of microbes.

Industrial Packaging

Using packaging items constructed of EPS plastic can assist in maintaining the safety of industrial goods while they are being transported and distributed. 

Protecting industrial products that are easily damaged, such as electronic components, glass, or medical devices, with EPS plastic in the form of foam that can be molded into various shapes is possible. EPS plastic is available in the form of foam.

How To Respond In The Event Of A Fire Caused By Expanded Polystyrene?

The presence of expanded polystyrene increases the risk of a fire. In the event of a fire, the following steps must be taken:

  • You may be exposed to a lethal gas in the case of a fire or explosion. Wearing a mask that filters the air you breathe is an absolute must if you want to be safe.
  • Water should be sprayed into the containers to prevent them from catching fire. Water is the most excellent way to extinguish a fire started in a heated container. This process must be repeated several times to put out the fire.
  • Spraying water straight on the flames will just make things worse. Sulfuric gases, which have a foul stench and may be harmful to those who breathe them in, may be released by the fire. Keep an eye out for it!
  • At all times, firefighters must wear protective clothing, including a flame-resistant coat, gloves, a helmet with a face shield, and rubber boots.

You can learn more here.


There is a risk of fire ignition when working with expanded polystyrene. As a result, it must be handled with caution and under all applicable health and safety standards.

Frequently Asked Question (FAQs): Is Expanded Polystyrene Flammable?

Is it possible to recycle expanded polystyrene?

The biodegradation of EPS is exceedingly slow, ranging from 500 to 100,000 years! Even in this situation, it is more likely to degrade than break down. When you dump expanded polystyrene in the trash, it’s there for the rest of your life.

What is the differences between EPE & PE?

In theory, since both EPE and XLPE are made from the same resin (PE) and are molded into buns or planks, one would expect their properties to be the same. 

However, due to differences in the manufacturing process, EPE is better suited for various packaging applications such as medical equipment, semiconductor equipment, IT servers, and autos.


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