Q&A Frequently Asked Questions

Is flexible urethane foam flammable?

The ignition point of soft urethane foam is approximately 410°C, which is roughly the same range as natural materials such as cotton, newspaper, and pine wood, synthetic clothing fibers such as acrylic and nylon, and plastic products such as polyethylene, polyvinyl chloride, and polystyrene foam.
Therefore, like these, it will not spontaneously ignite without an ignition source.
In recent years, technology has advanced and flame-retardant products have been developed, but this does not mean that they will not catch fire if there is an ignition or ignition source nearby.
When flexible polyurethane foam catches fire, if initial efforts to extinguish the fire are not successful, there is a risk that the fire will spread, just like with straw, cotton, paper, thread, wood, other rubber, plastics, and foam, etc. Therefore, they are all designated as "designated flammable materials" under the Fire Service Act. Please keep them away from open flames and follow the regulations for "designated flammable materials" when storing large quantities of foam or more.

What should I do if flexible urethane foam catches fire?

Water is the most effective way to extinguish a fire, so if a fire occurs in soft urethane foam, immediately pour a large amount of water on it.
Of course, using a powder fire extinguisher is also effective at the initial stage of fire extinguishing. However, in this case, there may still be embers remaining inside, so you should also pour on a lot of water. Also, if you are handling a large amount of flexible urethane foam and a fire breaks out, contact the fire department immediately.

Is there a risk of fire if I use soft urethane foam products as a kotatsu mat?

The normal operating temperature for soft urethane foam is generally 70°C. Therefore, when used as a kotatsu mat, if used properly, it will not exceed this temperature and there is no risk of fire.
However, please avoid placing it directly over or in contact with the heater, just like with textile products.

Is there a risk of fire when wrapping or covering hot water or steam pipes with soft urethane foam?

The temperature of hot water normally does not exceed 100°C, which is much lower than the ignition temperature of soft urethane foam (approximately 410°C), so there is no risk of it spontaneously catching fire.
However, if soft urethane foam is used for a long period of time under such conditions, it may deteriorate, so it should not be used as a cover for steam pipes.We recommend using it as a pipe cover for hot water pipes with temperatures below 50 to 60 degrees Celsius.

Is there a risk that static electricity that builds up in soft urethane foam could cause the foam to catch fire?

Soft urethane foam has low electrical conductivity and easily accumulates static electricity due to friction, but the static energy is so small that it is extremely unlikely to ignite the foam.
However, when attaching flexible urethane foam with adhesive containing a volatile solvent with a low flash point, care must be taken as static sparks can ignite the solvent vapor and cause the urethane foam to catch fire.
To prevent ignition, water-based or flame-retardant solvent-based adhesives should be used, and low-flashpoint solvents such as thinner, gasoline, benzene, and alcohol should not be allowed to soak into the foam in liquid or vapor form or brought into close proximity (to reduce the vapor concentration of flammable solvents in the workplace). Measures such as humidification should also be taken to suppress or eliminate static electricity.

Is there anything else that requires special attention when handling flexible urethane foam?

• (1) Flexible urethane foam soaked in flammable oils may occasionally emit smoke or catch fire even at low temperatures, so be careful not to pour water on it or heat it up. This phenomenon is not limited to flexible urethane foam, but can also occur with cloth and cotton. It is said that in environments where it is easily exposed to air, the soaked oils will autooxidize, causing the internal temperature to rise and causing the oils to emit smoke and catch fire first. This is the same phenomenon as when garbage burns with cooking oil.
• (2) There have been cases where sparks generated when cutting or welding construction materials have ignited soft polyurethane foam, so please make sure that there is no foam nearby when working.