Why we use intumescent paint coatings
Put simply, intumescent paint coatings are used for the protection of structural steel from the effects of fire.
- Steel loses strength immediately upon heating. This becomes critical from a structutal adequacy point of view when temperatures reach 300˚C.
- At a temperature of 550˚C steel will retain about 50% of its room-temperature load capacity.
- 550˚C is considered to be the failure point for structural steel columns that are exposed on all four sides.
- 620˚C is considered to be the failure point for structural steel beams.
- 700˚C is considered to be the failure point for structural steel supporting roof loads.
- Failure temperatures can be as high as 750˚C for partially-exposed structural members and/or under loaded sections.
Intumescent coatings, when correctly applied, are able to prevent the collapse of the steel structure of a building for a prescribed period of time, ensuring that the necessary fire ratings levels (FRLs) are achieved.
Intumescent coatings provide a means of achieving the required FRLs without having to encase structural steel components in concrete, vermiculite or fire-rated boards.
Apart from potential cost savings, this allows structural steel components to become an architectural feature of a building's design.
Intumescent's growing popularity
Intumescent coating systems are relatively new technology but they have achieved - and maintained - a majority market share. The graph below shows market share in the UK but the story is not dissimilar in Australia. This popularity proves the many benefits of using intumescent coating systems over older technologies.
Other options for passive fire protection of structural steel
Whilst we believe intumescent coatings provide a highly viable form of structural steel protection, it is not the only option. Here are some other options...
Vermiculite coatings
Vermiculite fire spray is an inexpensive form of fire protection that provides up to 240 minutes of protection to structural steel, ceilings and ducts.
Vermiculite is a cheaper option than intumescent coatings at FRLs of 90 or 120 minutes.
Vermiculite retains moisture that is released as steam in the event of a fire. The ensuing cooling effect delays the temperature increase of the steel providing a level of protection.
Whilst vermiculite is inexpensive, both in terms of material cost and application, it doesn't provide the aesthetically pleasing qualities of intumescent coatings.
fire rated boards
Fire rated boards can be applied to building elements such as structural steel, metal clad walls, timber floors, and concrete floors and walls to prevent the spread of fire, smoke and gases from one part of a building to another.
They provide up to four hours of protection and can be very aesthetically pleasing but are quite labour-intensive to install and, hence, expensive.
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