Understanding Fire Protection Through Protective Coatings
Intumescent coatings, often known as intumescent paint, are used in buildings or structures as a passive fire resistance measure. They can be applied to structural members as an aesthetically pleasing fireproofing product.
Understanding Fire Protection Through Coatings – Purpose
Intumescent coating delays the collapse of the structure through insulating the structural elements (columns, beams, floors and roofs) that support the building, thus helping achieve fire resistance levels specified in terms of time. Therefore it fulfills with the highest priority of passive fire protection, preventing the collapse of the building, allowing the time for safe evacuation of people from it, and making it safer for the emergency services and rescue team. The scope of intumescent products is the prevention of the structural collapse of the building, which can occur if load bearing steel elements reach a critical state. Contact Protective Coatings Cape Town for more information.
Feature of Intumescent Coatings
The key feature of intumescent coatings is that they expand significantly when exposed to high temperatures, such as those found in a fire. Some intumescent products can expand to more than 100-times the original thickness. As the product expands it becomes much less dense, which makes it act as in insulator that keeps the high temperatures away from structural members or protected openings.
Understanding Fire Protection Through Coatings -How Intumescent Products Work
Intumescent products are made of a series of chemicals suspended in a binder. When the binder is exposed to heat it begins to soften, which allows the suspended chemicals to the heat. The chemicals begin to react, which releases vapors that create a foam. A carbonization occurs and the foam solidifies into a black insulating material that is often referred to as char. Intumescent products are made of a series of chemicals suspended in a binder. When the binder is exposed to heat it begins to soften, which allows the suspended chemicals to the heat. The chemicals begin to react, which releases vapors that create a foam. A carbonization occurs and the foam solidifies into a black insulating material that is often referred to as char.
Application of Intumescent Paint
The paint product is applied to the steel in layers as needed to generate the thickness that corresponds to the level of protection mandated by the building code. A final layer of intumescent paint is mixed with pigments that provide the desired finish color for the steel.
Intumescent coating are an increasingly used way of providing passive fire protection to the load-bearing structures, especially structural steel, which is becoming more and more popular in modern architectural design of both industrial and commercial buildings. As a means of fire protection, it presents several advantages.
Other Advantages of Intumescent Coatings
- It does not modify the intrinsic properties of materials, like for example the mechanical properties.
It is easily applied.
- Different kinds of intumescent paint can be used on a variety of materials, such as steel, timbers, composite elements and concrete.
Understanding Fire Protection Through Coatings On Steel
For steel, this is linked to the critical temperature, defined as the temperature at which the load bearing capacity becomes equal to the effect of the applied loads (so the steel element is very close to the collapse). Critical temperature of steel can vary from 350 °C to 750 °C, depending mainly on the loading scheme, but in most of the cases between 500 °C and 620 °C.
Understanding Fire Protection Through Coatings On Concrete
For concrete, critical state is linked to the critical temperature of the reinforcing bars (normally from 350 °C to 500 °C) and the reaching of a temperature of 500 °C inside the concrete element.
How to correctly apply intumescent paints to steel materials
Intumescent paints are always part of a system. For steelworks, the system include an anticorrosive primer and (eventually) a topcoat. For the former, the scope is assuring adhesion to substrate in cold state, anticorrosion protection and stickability of intumescent char formed during fire exposure, while the scope of the latter is aesthetic function and, in case of specific atmospheric aggression, sealer function to prevent early degradation and inactivation of intumescent layer and weathering resistance to end-use conditions.
Before being coated with a compatible primer, steelwork must be prepared according to predetermined standards. If that is already the case, it must be cleaned and free from grease, oil, rust, dirt or any other contaminant that may inhibit the bonding.
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Topic: Understanding Fire Protection Through Coatings