Appropriate intervention: Fires in timber buildings under construction

It may not be obvious that a building has elements of timber construction. While a whole building may be constructed using a timber construction method, this can also be used when extending a building of traditional construction. An extension could be at ground level or on top of an existing building. Some buildings are designed with lower floors of traditional masonry or steel construction and upper floors of timber construction.

If the timber building under construction does not have passive fire protection, the timber will provide a combustible fuel source. The impact of this means that fires in large timber buildings under construction may be resource intensive. The lack of active fire protection in a timber building under construction may result in fire behaviour and growth that would not be expected if the protection was fully functioning.

Additional resources may be needed including personnel, equipment and water, and this should be given consideration early in the incident. For further information refer to Firefighting – Additional resources: Firefighting.

Operational personnel should be provided with information about current or temporary timber buildings under construction in their area if available. This information should inform the decision-making of the incident commander.

Early intervention by deploying appropriate firefighting tactics may prevent escalation. The firefighting tactics that should be deployed, and the speed and weight of intervention that will be required, should be informed by:

• Identifying the stage of fire development
• Assessing the construction of the building
• Considering the level of fire protection provided

The firefighting tactics deployed should take into account that natural or forced ventilation may accelerate fire growth and spread in a timber building under construction.

Firefighting tactics should also take into account that rapid firespread may occur or that structural integrity could fail rapidly. Therefore, the arrangements for evacuation and tactical withdrawal should be established for a fire in a timber building under construction. For further information refer to Incident command – Emergency evacuation and tactical withdrawal of responders.

External protection

To limit firespread or prevent escalation of the incident, the deployment of external firefighting tactics and various types of firefighting media may be necessary. The resources required to provide external protection and any impact on the safety of personnel should be risk assessed before proceeding.

As the radiated heat from a fire in a timber building under construction could affect the surrounding area, external protection, such as using water curtains, sprays or compressed air foam, may be needed. If not already on-scene, these additional resources should be requested. For further information refer to Firefighting – Additional resources: Firefighting.