In recent decades, with the improvement of sustainable development and energy efficiency, modern buildings have developed rapidly. However, increasing the priority of fire safety is not that important, and we need to rethink our approach.

Combustible cladding materials commonly found in buildings cause safety hazards. The system originally used to help solve this problem is not good enough. Therefore, my colleagues and I created a cladding material library, which is an online database that provides insight into the flammability of various cladding materials.

The cladding materials used in modern rain protection systems on the exterior of buildings provide thermal insulation and protect the building from rain, wind and sunlight. They also allow architects to create interesting architectural designs, for example by adding bright colors or curves to the exterior.

However, in addition to other shortcomings, the flammability of modern siding materials has led to more and more fires worldwide. For example, the hockey fire in Melbourne in 2014 and the Grenfell Tower fire in London in 2017.

The extent of the problem

Many cladding materials currently in use are flammable to varying degrees, including the very common aluminum composite panel (ACP). These have a plastic-based core material (such as polyethylene) and are glued with an aluminum plate on either side. Although ACP is sometimes almost non-flammable, it is generally considered flammable.

In Queensland, approximately 18,000 buildings have been inspected to determine the flammability of the cladding and the overall response of the building to the fire. Among them, 75% do not need to take further measures. For the remaining 25%, engineers were hired to further investigate whether they had problems.

The Queensland State Government estimates that 100 to 200 buildings need to be made safer, while the cost of working on one building is as high as tens of millions of dollars.

It is important to note that some buildings have combustible cladding that would otherwise have strict fire protection design. For example, the fire door network is well maintained, the escape distance is short, the firefighter passage is good, and the layout minimizes the risk. Therefore, having a flammable exterior wall does not necessarily mean that the building is dangerous.

Nonetheless, such materials should not be included without the architects, engineers and builders correctly understanding the risks involved.

To help research, a database was developed

The database created by my colleagues and I is the first such database, which provides a detailed collection of flammability information and material properties for different types of common coating materials.

Usually, because there are only so many products on the market, the same materials are reused throughout the building.​​​ We use a small scale test (10 cm sample) to determine which material is most important.

But the identification material is not enough to understand its performance in fire. Therefore, we have completed flammability tests on 20 common materials outside the building (samples not exceeding 1m in length).

In one year, we took 1,100 small material samples from the building and conducted 9,250 tests. Then, we identified 75 unique cladding materials and narrowed them down to 20 materials, and then conducted detailed tests on them (approximately 30 tests for each material). We have selected a variety of materials to ensure that the most common materials appear in our selection.

The experiment we did involves exposing the material to heat in a controlled manner and then changing the heat to see how the sample responds. Our process includes measuring the time it takes for a material to ignite, the amount of heat released from the material, how the heat is released, and how the flame spreads.

Now, our results are publicly available in the cladding material library, which can be updated as new materials are invented. The database will help fire engineers to effectively assess the potential fire risks of buildings.

Writing accurate reports is essential

Fire engineers can use our database to determine the overall performance of a building in a fire. Then, they may ask the following questions:

How long will the fire spread to the building?
Can people reach a safe place in time?
Are there any flammable substances near important escape routes?
If the fire spreads upwards, how will the rest of the building function?

However, fire engineers participating in such investigations also need continuous training to update their knowledge. For many people, this is a continuing professional development course designed by the University of Queensland and similar courses offered by the Queensland government for construction professionals such as builders and architects.

The latter is essential to the success of our project because it enables construction professionals to understand current issues and reports prepared by engineers.

Currently, fire engineers hired by the government or building owners are making immediate changes to related buildings to improve their short-term safety. In the end, they will make suggestions on how to improve the long-term safety of the building, which may cost more time and money.

The only way to solve the fire risk is to understand the performance of each building and have a qualified engineer responsible for its design.

Our research will represent a change in the way we solve this problem and hopefully prevent fires in the future.