Flame spalling is used for surface cleaning and pre-treatment of concrete and steel. Block burners with a series of closely spaced heating flames are guided directly over the surface to be cleaned.
When spalling concrete, the short-term heating of the surface leads to the flaking of a thin layer of weathered concrete. Any existing build-up, such as paint, moss or other contaminants, is also removed.
When spalling steel, rust, scale and other contaminants on the surface are burned or melted and mechanically removed by the pressure of the flame.
The result is a clean surface which is suitable for coating or welding processes. Common usage is, for example, in shipbuilding or bridge construction.