Is Polyurethane Flammable? Discover The Truth Now

Your daily activities often involve the use of polyurethane materials. For example, the couch in your living room and your mattress contain polyurethane foam.

But in the spirit of fire safety and caution, we'll answer the question – is polyurethane flammable? This article provides information that can reduce the chances of a polyurethane fire accident.

Is Polyurethane Flammable

Is Polyurethane Flammable?

The answer is yes. Polyurethane is flammable. For a substance or material to be considered flammable, it should ignite through slight contact with naked fire. Liquid polyurethane will ignite and burn quickly. It is more flammable than solid or molded polyurethane due to the absence of flame-retardant chemicals. 

How Flammable Is Polyurethane?

The flammability of polyurethane depends on its state and purpose. Polyurethane is plastic. Most plastics come in liquid forms at high temperatures before they are molded or blown. So manufacturers may add flame-retardant chemicals to prevent or slow down the rate at which a material catches fire.

These flame retardants often form a protective layer around the material's surface, slowing ignition. However, its pure liquid form is quite easily ignitable, with a flash point between 255°F - 300°F.

Although National Fire Protection Association (NFPA) describes flammable substances as ones possessing flash points below 100°F, polyurethane is still considered quite flammable.

What Is Polyurethane?

Polyurethane is a plastic polymer used in place of rubber. It’s used to create flexible foams seen in mattresses and upholstery, rigid foams in the construction of airplane wings, molded foams, adhesives, sealants, and coatings. Polyurethane is a synthetic material that can be fibrous, resinous, and even elastic.

Polyurethane has two primary ingredients: polyol and diisocyanate. Polyol is an alcohol with multiple reactive oxygen groups, while diisocyanate is an organic compound with two isocyanate groups.

When you mix these two ingredients, they polymerize (react and combine) to form long chains of molecules called polyurethane polymers.

The resulting substance can be rigid or flexible, depending on the ratio of ingredients used. For example, polyurethane has a very low thermal conductivity and is often used as an insulating material.

The low thermal conductivity of polyurethane means that it doesn't conduct heat very well, which makes it a good insulator.

How Flammable Is Polyurethane

Uses Of Polyurethane

Polyurethane is an incredibly versatile material with a wide range of uses. Prominent examples are the thermal insulation of buildings and refrigerators. Another example is the weight-reducing applications of polyurethane-based foams and adhesives in vehicle transport manufacturing.

In the automotive industry, it's often used in car seats, dashboards, and other interior components. It's also utilized to manufacture some car parts, like suspension bushings. In the construction industry, it’s used as an insulator, sealant, or adhesive.

Spandex is a standard synthetic fiber made of over 80 percent polyurethane in the textile industry. Polyurethane is also used in furniture, as it's a very durable material able to withstand a lot of wear and tear. In addition, it's used in many types of flooring, including hardwood floors and laminate floors.

How To Safely Work With Flame And Polyurethane

Except for a job that entails purposely setting polyurethane on fire, I don't recommend you do so. However, when working with fire and polyurethane, you should keep a few things in mind to stay safe.

  1. Always use a flame-resistant surface when working with fire and polyurethane. This will help to prevent any accidental fires from starting.
  2. Ensure that you have proper ventilation in your workspace. This will help dissipate any fumes created when working with polyurethane.
  3. Never leave polyurethane unattended when you have a flame going. Ensure to extinguish any fire before leaving the area to avoid accidents.

How Often Can Polyurethane Catch Fire?

Well, not often. As in most cases, it is set on fire by a naked flame and not necessarily through self-ignition. Also, the type of polyurethane and its use can increase or decrease the chances of a fire starting. For example, polyurethane foam is more likely to burn than polyurethane suspension bushing in cars.

So, if you're using polyurethane in your home, it's essential to be aware of this and take precautions. Keep any heat sources away from where the polyurethane is being used, and never leave polyurethane unattended when in use. It's always a great idea to have a fire extinguisher on hand. And, as always, practice safety first!

Is Polyurethane Flammable When Dry

Is Polyurethane Flammable When Dry?

The answer could be more complex due to the multiple compositions of dry polyurethane products. The safest thing to do is to treat your polyurethane products as flammable until proven otherwise by the manufacturers.

 Liquid polyurethane can undergo spontaneous combustion, i.e., self-heating or auto-ignition. If liquid polyurethane spills and is mopped up with a cloth, the cloth can auto-ignite and start a fire. As the rag dries, the polyurethane oxidizes and generates heat.

If the rag is stacked with other materials that hold the heat, it reaches its flash point and ignites. Therefore, it's best to soak the soiled rag in water before spreading it in an open space to dry.

How To Put Out A Fire From Polyurethane

It's important to avoid a fire accident with polyurethane by taking precautions when using and storing it. When polyurethane catches fire, it creates a scorching flame that can cause severe burns. Your best option is to use a fire extinguisher or dry chemicals and foam to put out the fire.

Contact the nearest fire station if the fire spreads and becomes more than you can handle. The fumes from the burning plastic are also toxic, so ensure you move to a well-ventilated area and contact your physician in cases of irritation.

Final Thoughts

So, is polyurethane flammable? The answer isn't straightforward. In its pure state, polyurethane will burn with little to no effort and can even oxidize and self-ignite.

However, most polyurethane products have very high flash points and contain chemicals that reduce flammability. It's best to keep all your polyurethane products away from the fire because they will burn at the right temperatures.