EV charging stations made of wood? Fireproof coating a new revolution

We only need to reflect on the Great Fire of London, one of the most devastating historical catastrophes (1666). Due to the prevalence of timber in building construction at the time, a sizable portion of central London was completely burnt to the ground.

Cases like this are the reason why many current construction rules require that wood be used only after treatment.

But what if we could bolster engineered timber's resistance to fire so its uptake in the built sector can grow? This is where a coating that can "fireproof" wood comes in.

Even better, at only 0.075 millimeters thick, it's hidden from the naked eye and retains the beauty of wood- something competing materials lack. 

The coating was developed by researchers at Nanyang Technological University in Singapore (NTU Singapore). 

Interesting Engineering (IE) interviewed Associate Professor Aravind Dasari, the team lead, to discover more about the invention's future. 

What makes this fireproof wood coating unique?

"Aesthetics coupled with sustainability concepts are important in the modern construction and building sector," Dasari told IE.

"This is where wood-based (mass-engineered timber) designs in construction have taken the limelight in recent times." 

He explained that the flammable, or combustible, nature of wood has ensured that wood-based designs are clad with either gypsum or refractory panels painted with intumescent (fire-protective) coatings.

This makes sense and means that the global fire-resistant coating industry is expected to grow to a US$1.06 billion market by 2029. 

However, "This process of cladding or coating hides the natural beauty of wood!" he said.

"Our technology's coating is transparent, has very good protection against fire, produces very little smoke, and is low-cost and easy to apply." 

And that's not all. The novel fireproof coating has passed industry-standard tests with flying colors. 

For instance, the "made-in-NTU" coating received the highest class possible in the Single Burning Item testing carried out at a third-party accrediting laboratory. The coating produced less smoke when exposed to a high-temperature flame and prevented the flames from spreading.

In context, there aren't many items on the market that can offer both transparency and fire resistance. And products that advertise having both qualities cannot meet the international requirements for industrial use.

Additionally, Dasari explained that "there are other products which are transparent and fire-retardant. But, they may be harder to apply [for example, some require wood immersion] and are quite expensive." 

How does the technology behind the fireproof wood coating work?

"We mixed a concoction of special chemicals which can be easily painted or spray coated on wood, which is thin enough and transparent so that it doesn't hide the beauty of wood," he said.

According to the materials science engineer, the technology behind the coating locks in certain compounds that, when exposed to heat, interact systematically with the resin in the wood. This sparks a chain reaction that develops extremely heat-resistant char – a thick layer of bubble-like foam material- that insulates the wood underneath from the high heat.

As per a press release, the char expands to more than 30 times its original thickness. "The air bubbles within this foam keep the heat away from the wood and prevent further burning, as air is a very good insulator against heat," he added.

A Youtube video also revealed that when the char is scraped off, the wood behind it is still intact, demonstrating how effective the coating was in protecting the wood. 

What are some real-life applications of fireproof wood?

Dasari explained to IE that the team's technique would enable the use of wood in its natural form for construction purposes. He also stressed that compared to other building materials like concrete, wood is one of the most sustainable building materials because it is carbon negative.

"Could we one day have wooden refueling stations or EV charging stations? Could we retrofit older wooden architecture or heritage buildings and protect them with our coating? I think our technology opens up many applications and doors," he expressed. 

Better yet, the team has received requests about whether their coating works on wooden furniture too. "And it does!" claimed Dasari, "since it can easily be hand-painted on like a brush, just like varnish."

Could NDU's fireproof wood coating revolutionize the timber construction industry?

Professor Louis Phee, vice president for innovation and entrepreneurship at NTU, called this development a significant advance for the timber construction sector.

"Leveraging on NTU's strengths in materials sciences and engineering, this is an example of how fundamental research can be translated into commercial applications with high impact, given that the invisible coating enhances both safety and aesthetics in timber construction with few to no drawbacks," he said.

Dasari revealed to IE that the team has already licensed the technology to a local company (in Singapore) called Venturer Timberworks, which has businesses worldwide and supplies mass-laminated timber for the construction industry.

Still, we can expect other stakeholders in the mass timber construction sector to look to use the new coating to improve fire resistance in their future projects. After all, suppose it lives up to its standards for reducing cost and reliance on other, more expensive solutions (not to mention the natural beauty and sustainability aspect). In that case, NDU's coating does appear to be a logical step forward. 

IE wanted to learn of any limitations of the coatings technology; however, Dasari did not elaborate on this. But, we do know that the team aims to collaborate with other industry partners in the future to test the durability and efficacy of the coating more thoroughly.

"Hopefully, we'll be able to test the coating out at a larger scale on load-bearing structures, which will pave the way for further industry adoption," Dasari concluded.