In a statistical study performed by the London fire brigade in the Real Fires Database it was found that out of 30 086 fires occurring between 2009 and 2011, fire spread beyond the floor of origin through gaps or voids occurred in 92 cases. This illustrates that the phenomenon is relatively rare. However, it can lead to severe property damage. Fires can spread invisibly within cavities of the structure, which has led to problems concerning the extinguishment of the fire. Cavity barriers function is to stop the fire spread through cavities. However, these cavity barriers have not always been effective.

This report is the result of a study that aimed to:

1. Develop a robust testing method for cavity barriers for cavities with combustible materials within walls, floors and other elements in buildings.

2. Provide guidelines for the materials, installation, positioning, detailing and location of the cavity barriers.

Additionally, a preliminary study is performed to assess some extinguishing strategies.

Based on a study of characteristics of cavity fires, current standard fire tests for cavity barriers were revised for the use in cavities with combustible materials. From tests following the revised methodology, guidelines regarding the dimensions, installation and fire stopping design are provided.