The Importance of Intumescent Paint Coatings

The best-designed buildings have to be structurally safe, functional and aesthetically pleasing. The combination of more complex structures for residential as well as commercial and industrial buildings, together with stricter building and safety regulations, have brought any given building's fire performance to the fore.

Building codes can only stipulate a minimum fire performance. The temperature of a fire can reach up to 1,000 degrees Celsius, as will the temperature of any steel structural elements or cladding within the building or on the outside. Once steel reaches its critical temperature, it loses its load-bearing capacity, starts to sag and may cause the structural collapse of a building, endangering any people inside and close by outside. Non-fire-protected and semi-molten steel cladding could trigger further fires and dangerous chemical reactions in a building's contents.

A solution to this dilemma is a thin film of intumescent coating, which will make beams more fire-resistant. It can be applied in a series of colours (see the range at www.colorcoat-online.com) without compromising a building's aesthetics or accessibility, yet making it fire-proof for a long enough time until the fire itself can be extinguished.

However, it's important not to confuse intumescent paint with fire-retardant paint. The latter only slows the burning — it does not halt it.

Intumescent paint looks like a conventional coating on steel beams or other structural elements, or on interior or exterior wall and roof cladding. It works on the basis of a chemical reaction that can keep the temperature of the steel under it below 550 degrees Celsius. The paint itself consists of four components:

• A surface preparation

• A primer

• A base coat that is the intumescent coat

• A top seal

The base coat that provides the fire-proofing consists of a catalyst, a binder, a carbohydrate and a foaming agent.

When a fire starts, the coating softens. The temperature increase causes a chemical reaction, making the catalyst decompose into an organic acid. This in turn combines with the carbohydrate to form a carbon char. Meanwhile, the foaming agent emits large volumes of non-flammable and non-toxic gas, which reacts with the char to form a solid insulating layer. This means that the heated coating expands many times over the original steel and protects it. As a result, the paint prevents the collapse of the structure for a period of time until help arrives.

Intumescent paints are especially useful for protecting escape routes or providing fire-resistance in those parts of a building that could be structurally difficult to modify or to repair. However, it is very important to ensure that the structure over which it is applied is in good repair. Poor workmanship can cause serious delamination in an intumescent coating within just a year.

It's also best to use specialist contractors to apply these coatings. They should be certified by a competent professional organisation and their work approved by local authorities as compliant with building regulations and insurance requirements.