Intumescent paint is used in buildings to provide passive fire protection. It is typically used to protect structural members whilst also being aesthetically pleasing. Intumescent paints are referred to as reactive coatings, meaning intumescents expand upon exposure to extremely high temperatures. Intumescent products expand up to fifty times thicker than their original thickness. This expansion creates a char which provides the thermal insulation necessary to protect the structural members from the high temperatures experienced in a fire.
Intumescent Paint: How it works
Intumescent paint is made by suspending a chemical series in a binder. Upon exposure to heat, the binder softens allowing the suspension of chemicals to react with the heat. The reaction results in vapors that in turn produce foam. The foam carbonizes into a black material which insulates the structure under it. This material is often called char.
Using Intumescent Paint to prevent structural damage
Intumescent paint is typically used in buildings on exposed structural members made of steel, so that they may look aesthetically pleasing.
The thickness of intumescent or loadings that are applied to the structural member are in accordance with the level of protection that is deemed necessary according to the buildings fire design and the A/V Section factor of the steel member. The A/V factor is a function of the area of the steel member exposed to the fire and the volume of the steel section The higher the A/V, the faster the steel section heats up, and so the greater the thickness of intumescent fire protection required. Th esection factor and limiting temperature are then used to determine the thickness of protection required.
Intumescent paints can be coloured to match the building designer’s needs. This element is known as top seal and its inclusion in the system can also provide resistance to environmental conditions, allowing it to be used in areas of higher humidity and where there may be excessive moisture.
Other Intumescent Firestopping Products
There are other intumescent products besides intumescent paint. Intumescent is used as a firestopping material for protecting penetrations passing through compartment walls and floors. Hence it can be used for protecting the space around cables, pipes and other penetrations.
Services holes are often created in walls and floors to allow for the passage of cables or pipes. In order to maintain the integrity of fire protection, intumescent wraps or collars are used around the cable/pipe. In the event of a fire, the intumescent will expand, preventing smoke and flames from passing through the void that would be created as the pipe or cable is destroyed by the heat of the fire.
Another product like that is the intumescent putty pad. These are thin putty sheets that can used to wrap any non-fire rated object such as back-boxes. Building regulations frequently restrict the extent of penetrations in a given area of the compartment wall or floor. However, it may be a necessity to keep many devices and outlets in that element of the compartment. In this case, intumescent putty pads are used to cover the back side of every device/outlet. This maintains the continuity of the fire barrier.