Brickwork is made of materials that are not normally combustible, such as cement, brick and plaster, and by their very nature they contain a considerable amount of water. These features mean that any brickwork wall has intrinsically good fire resistance and this property is particularly linked to the thickness of the wall.
In general load-bearing brickwork walls are sizeable enough to deliver the fire performance required for most buildings, as defined in the tables shown in the Eurocodes and other national standards. The approach changes for non-load-bearing walls which are usually less thick, and their compartmentalising function imposes particular performance requirements.
One way of improving their performance can be to increase the thickness of the wall so as to adapt it to the new rating requirement. However, this is often not possible for practical reasons. Increasing wall thickness means sacrificing room space and size, and work has to be done on installations and pipework, in addition to the obvious complexity of the work which can only be done when the building is empty.
It therefore becomes necessary to use products and technologies that can improve the existing walls without the complexity of making them thicker.
Protective coatings for brickwork structures are normally divided, according to their application, into intumescent paint, spray plasters and covering panels. The choice of protective system to apply in the various situations planned for, takes many different factors into account, for example architectural needs, economic factors, environmental conditions, and the fire-resistance rating prescribed for the building.
In particular, reactive paints and varnishes when applied look just like normal paint or varnish and they do not alter the appearance and the geometry of the structural elements to which they are applied. In the event of fire however, as the temperature rises, they react chemically, changing into a carbonaceous foam with excellent insulation properties, whose thickness swells to 80/100 times that of the original coating, acting as an effective temporary barrier protecting the element.