Research has shown that ember attack on houses is the main cause of house fire during bushfire. This is despite the long held view that house fires start by direct flame contact by the bush fire front. Ember attack can occur for up to 30 minutes before the bushfire front passes a given house, whereby embers ranging from tiny sub millimetre sized sparks to large inch sized chunks  of on-fire wood and bark fly down onto and into a house.

Much of regional and urban fringe towns and cities in Australia are susceptible to ember attack and subsequent house fires, and this is sadly true of many of the bushfires that have raged in Australia over the years. This was all to true in the recent Black Saturday bushfires in Victoria in 2009. After the Royal Commission to the Black Saturday bushfires, several recommendations about house design were offered down. Specifically, it was recommended that houses be designed and built in such a way that embers have less chance of settling on or inside a house – and subsequently setting it on fire.

One way of improving the design of houses to lessen the chance of embers settling on or inside a house is to use CFD modelling to predict where embers travel during ember attack on a house. This has been achieved by Synergetics by using a technique called Lagrangian particle tracking – whereby the airflow around a house is calculated, and the particles influence by the air flow is determined.  An example of this is shown in the pictures on the left; firstly of the air flow around, under and inside the house, as well as the embers paths (middle), and bottom right shows the final resting place on the outside of the house. The total ember capture rate is calculated for a well designed and poorly designed house, as shown in the table.