Flammable foam cladding presents a genuine risk to life and property; the use of non-compliant cladding during construction can have a significant effect on how your building or home will respond to a fire.

Non-compliant aluminium composite panels (ACP) and expanded polystyrene (EPS), in particular, can be extremely dangerous during a building fire. When used externally, these materials can accelerate the spread of fire, increasing the risk factor.

Understanding composite panels

Composite building panels (including ACP and EPS) represent a range of prefabricated insulated building materials usually comprising of two metal sheets bonded to an inner core of insulation. Some products use a plastic or fabric lining instead of metal skins.

Composite panels are of various types, differentiated by the core material used to provide insulation. The type of insulation material used is the single most important factor in relation to the performance of the panels in a fire.

Some of the insulation cores include: Expanded Polystyrene (EPS), Aluminium (ACP), Fire Retardant EPS, Polyurethane (PUR), Polyisocyanurate (PIR), Modified Phenolic, Foamed Glass, Glass Fibre and Mineral Wool.

These types of composite panels have found increasing acceptance in the industry, and are used in modern buildings and homes, either externally as a wall or roofing material or internally to divide or line the house. While these panels are cheap and easy to install, and provide a good level of insulation, they do experience a number of significant problems when it comes to fire protection, which is a serious consideration when building in fire-prone Australia.

Why some building panels are more of a fire hazard than others

When exposed to fire, composite panels have been known to experience a number of problems. For instance, when a fire from outside the panels creates enough heat to impact the insulation core inside the panel, delamination occurs and the panels lose their structural stability. Additionally, composite panels such as ACP and EPS are prone to melting, dripping and collapsing, which make them very unpredictable materials if they catch fire.

Composite panels also feature combustible cores that can catch fire inside the insulation core either from an electrical cable fire or a building fire. Once these cores catch fire, they are extremely difficult to extinguish as the two outer layers of material prevent the water from penetrating into the fiery core. The fire can escalate quickly and get out of control, damaging or destroying the building.

Composite panels and wood react differently to a fire. Elements such as polyethylene and polystyrene in a composite panel will release two and a half times the amount of energy compared to an equivalent amount of wood. Polystyrene, in particular, is also defined as a thermoplastic, which reacts dangerously to fire – a single kilo of polystyrene releases more energy than a litre of petrol when alight. This means that these types of composite panels can burn up quicker and more ferociously than a natural substance. Aluminium used in ACP is also a great conductor of heat and can accelerate a fire by drawing it up and around a building.

Also, depending on the type of insulating core used, a fire involving composite panels can create a large volume of dense smoke, which is usually toxic to those that inhale it.

While there are composite panels in the market that incorporate fire retardants, these do not prevent combustion from large fire sources and may also leach over time, reducing their effectiveness.

Use fire-resistant cladding to protect your home

When you are considering a cladding material for your next building project, choose fire resistant cladding such as Durra Panel for your internal walls and ceilings.

Durra Panel is a one-of-a-kind naturally fire-resistant building panel that doesn’t release any toxic fumes, flaming droplets or dense smoke during a fire. Used in interior cladding applications, Durra Panel is not considered a composite panel as it is made entirely of straw wrapped in a Kraft paper liner. When exposed to fire, the liner carbonises the straw (unlike composite panels that experience delamination), hindering the flame from penetrating the densely compressed panel core and preventing the fire from spreading further.

Durra Panel has been successfully tested for its fire resistance in accordance with Australian Standards and global certification – the panels is also FM approved as a Class 1 ceiling construction material.

How a Durra Panel reacts to fire

The Durra Panel core is made up of densely compressed straw. When the panel is exposed to fire, the Kraft paper lining burns off, and the panel core carbonises to form an amazingly effective barrier against the spread and penetration of fire. Once the flame is removed from the panel, the carbonising ceases, the embers disappear and the panel will not smoulder, curl up or distort.

Additionally, Durra Panel’s thermal insulation also provides a safe barrier during a fire – one can safely touch the reverse side of the board without experiencing any heat from the flames.

In a bushfire situation, one of the biggest causes of death is exposure to radiant heat. The fire-resistant properties of Durra Panel cladding provide protection against radiant heat and bushfire flames. With a fire rated panel-to-panel joint, Durra Panel has a CSIRO fire resistance test rating of 1 hour.

Combining the Durra Panel protection with a comprehensive bushfire plan will help keep a building’s occupants safe as the bushfire passes through, usually between 2 and 5 minutes.

Watch Durra Panel in action.