Intumescent paint for steel

intumescent paint for steel is applied in skyscrapers to improve fire safety

Increase fire safety with intumescent paint for steel

Fire is a danger to buildings no matter what material they are made from. Steel may not burn, but the extreme heat of a blaze will damage it, weakening its structure and leading to building collapse. By protecting steelwork with intumescent paint for steel, up to 120 minutes of fire protection can mean the difference between a near miss and destruction.

Intumescent paint for steel effectively protects steel from the dangers of fire by providing an insulating layer between the material and the flames.

Intumescent paint for steel protects from collapse

Applying intumescent paint for steel saves buildings and lives

Applying intumescent paint for steel saves buildings and lives

Steel begins to lose strength at about 300ºC, and this increases rapidly after 400ºC. Given that the average housefire burns at about 600ºC and industrial fires are much hotter, this is a concern for building and human safety.

At ~200/250ºC, intumescent paints undergo a reaction and swell to up to 50 times their original size, forming a solid foam-like char.

Intumescent paint is the preferred method for fireproofing steel. The expanding reaction happens at temperatures low enough that no damage has yet been done to the steel, and can provide up to and including 120 minutes of fire protection. This gives precious time for fire crews to get the fire under control without the risk of the building collapsing around them.

Intumescent paint for steel; structural steel, steelwork and steel beams

Intumescent paint is one of a range of fireproof paints. Also known as fire resistant, intumescent paints can be combined with fire retardant coatings to provide an even higher degree of fire protection. Available as water- and solvent-based coatings, intumescent paints are quick to apply and provide a smooth and durable decorative finish to structural steelwork in both internal and external locations. The protection time is dependent on the type of coating and the thickness of the steel structure.

Thin film intumescent coating for steel

On site application of intumescent paint for steel

On site application of intumescent paint for steel

The thin film coatings practically have three components: primer, base coat, and sealer. The base coat is the layer which expands and insulates against fire.

These coatings are common in buildings where the fire resistance must comply to the requirements of 30, 60, or 90 minutes protection.

Thin film coating applications can take place on site or off site. The on site applications usually involve a water-based paint system, even though solvent-based products are also suitable so long as the environment is not hot/warm and dry. It is possible to make almost all the coatings aesthetically appealing by applying another coating on top of the fire protection layer.

Thick film intumescent steelwork coatings 

Thick film coatings are usually intumescent epoxies which have a much higher thickness than the thin film coatings. These coatings are typically applied when the environment is too severe for the thin film coatings.

The thick film coatings are most common in exterior steel structures, for example in skyscrapers and marine environments.

Thick film coatings are suitable for on site and off site applications. They can additionally be supplied as pre-made casings.

Off site intumescent steel paint

Applying thin film intumescent paint for steel off site has been a great success in the UK. It allows for quicker construction and the opportunity for better quality control. Additionally, off site applications improve site safety, reduce site disruption and result in cleaner sites. Off site applications are common in non-aesthetic end uses, and application costs are higher than on-site application.

Intumescent paint for steel cost

There is a wide range of intumescent paints for steel available, and the following is an overview of products with prices including VAT.  A full range of top sealers, both water- and solvent-based, are also available to complement intumescent steel paint.

BrandProduct typePrice
Thermoguard Thermoguard Thermocoat W: Waterborne intumescent paint system providing fire resistance to structural steel and cast iron for up to 90mins.£86.40 (5Kg)
BollomBollom Fireshield Ultra Universal: A single pack solvent-based intumescent coating for fire protection of both internal and external structural steelwork.£368.66 (10L)
ZeroflameZeroflame Aquasteel WB+: Easy to apply, quick drying intumescent paint for standard steel sizes and profiles. Available for 30 and 60 min fire prevention.£174.20 (10L)
Sherwin-WilliamsSherwin-Williams Firetex FX5060: a water-based thin film intumescent coating for 60 minutes fire resistanct on structural steel.£212.77 (20L)

Alternatives for intumescent paint for steel

  • Boards are common in the UK. They provide a box-like fire protection around simple and more complex steel structures. Their benefits include being factory made with a guaranteed thickness, and a dry application.
  • Sprays are not so common in the UK even though they have some benefits such as low costs and ability to fireproof complex structures.
  • Flexible blanket systems are used where dry application is needed with complex structures. They are capable of being bent into shape.

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