Coating technology beats the heat

 

By Aravind Dasari and Dean Seah

Creating materials that can withstand fire or prevent it from spreading quickly is incredibly important in industries where keeping people safe is a top priority. Imagine the materials used to construct the buildings where we work and live in: they should be made of strong, fire-resistant and flame-retardant materials that retain their integrity in the event of a fire.

Most research in the field of material flammability focuses on the qualities of the materials themselves, such as how well they can withstand heat and how long they take to burn. Nonetheless, for a multitude of fire-protection material applications, as in construction, marine and offshore industries, the requisite fire-performance parameters differ significantly, necessitating large-scale testing which is conventionally both time-consuming and resource-intensive.

As a result, many questions have been raised on the validity of the thermal and flammability tests done using academic approaches to predict how well fire-protection materials perform in real-world scenarios.

Our team distinguishes itself by rigorously investigating the combustion behaviour of materials and systems across varying scales – from individual materials to components and entire structures – in close collaboration with industrial partners and regulatory bodies. In this way, we are able to overcome substantial barriers in the transition from research to commercial viability.

We have successfully designed and engineered flame-retardant polymers, composites, foams and a plethora of coatings, including one called “FiroShield”. Additionally, we have pioneered core materials for aluminium composite panels, natural fibre-based panels and geopolymer composites with inherent fire retardant and resistant properties.

Our scientific discoveries have not only been featured in peer-reviewed publications, but have also led to numerous technology disclosures, a significant number of which has been commercialised through licensing agreements with corporate entities.

 

ULTRA-THIN FIRE PROTECTION

One notable technology disclosure, facilitated through NTU’s innovation and enterprise company NTUitive, concerns the licensing of a transparent fire-retardant coating developed by our team.

This innovative coating is designed to shield mass engineered timber, a construction material garnering increasing interest due to its potential to expedite construction timelines by up to 35% through offsite prefabrication.

The natural wood grain of mass engineered timber contributes to its aesthetic appeal. When sourced from sustainably managed forests, buildings constructed from this timber variant have the potential to exhibit a reduced, or even negative, carbon footprint, in comparison to those constructed using steel or concrete.

Nonetheless, given timber’s inherent flammability, protective measures are imperative. Current practices involve encasing the timber in gypsum or magnesia fire-retardant panels or applying fire-retardant coatings – both of which obscure the timber’s natural wood grain.

Our research endeavoured to surmount this limitation, culminating in the development of a transparent fire retardant coating that maintains the visible natural aesthetic of mass engineered timber while safeguarding it against fire.

Upon exposure to fire, the coating undergoes a chemical reaction, causing it to expand over 30-fold in thickness and forming a char layer that insulates the timber beneath from the flames.

This versatile coating is also applicable to other engineered wood-based products used in the building and construction sector, be it for architectural structures or internal linings, decking and flooring.

LAB TO MARKET SUCCESS

In partnership with Venturer Timberwork, a Singapore-based mass engineered timber design and build firm, our research has addressed numerous industrial challenges.

Our coating was tested against industry standard fire classification protocols and we eschewed the use of halogen containing additives, known for producing toxic emissions upon combustion.

Experimental comparisons between wood treated with our coating and untreated specimens revealed a pronounced reduction in heat release rates and flame spread inhibition with minimal smoke produced.

Even a coating of minuscule thickness, comparable to a strand of human hair, achieved excellent ratings under European fire reaction standards for building materials, alongside fulfilling an International Organisation for Standardisation benchmark for product ignitability.

Venturer Timberwork has obtained exclusive rights to this innovation and has pursued further testing, obtaining regulatory approval for its application in several construction projects in Singapore. They have also partnered with Japan’s Kajima Technical Research Institute to adapt the coating for Japan’s mass timber building market.

A crucial factor in the scalability of the NTU-developed coating lies in its amenability to factory application, a feasibility rendered by its robust epoxy-based formulation, which distinguishes it from other water-based alternatives. Among the manufacturers interested in adopting this factory-applied coating is the Versowood Group, Finland's leading private sawn timber producer and processor.

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