What Does Intumescent Paint Mean In Construction?
What Does Intumescent Paint Mean In Construction?
Intumescent paint is a type of coating used in construction that responds to heat exposure by swelling in a controlled manner.
This swelling causes the paint to increase in volume and decrease in density resulting in the formation of a carbonaceous char layer that acts as insulation to protect the substrate.
The purpose of using intumescent products is to prevent the structural collapse of buildings, which can occur when load-bearing steel elements reach a critical state.
The critical state for steel is defined as the point at which the load-bearing capacity becomes equal to the effect of the applied loads and can occur at temperatures ranging from 350 °C to 750 °C, depending on the loading scheme. However, in most cases the critical temperature for steel is between 500 °C and 620 °C.
For concrete, the critical state is linked to the critical temperature of the reinforcing bars, which is typically between 350 °C and 500 °C and reaches a temperature of 500 °C inside the concrete element. \
In the case of wood, the critical state is linked to the residual section of the timber load-bearing element after burning.
Intumescent coatings are commonly used to protect structural steel elements in buildings, as they can delay the temperature rise and extend the time before the critical temperature is reached allowing for more time for occupants to evacuate and for fire-fighting measures to be taken.
Intumescent coatings are often used in conjunction with other fire protection measures such as fire-resistant barriers and sprinkler systems to provide a comprehensive fire safety solution for buildings.
How Does Intumescent Paint Works?
Intumescent paint is a special type of coating that can provide insulation from intense heat when exposed to high temperatures, typically around 200-250°C.
This is achieved through a complex chemical reaction that causes the paint to rapidly expand and form a stable, carbonaceous char that can extend up to 100 times its original thickness.
When applied correctly, intumescent paint can help prevent a building’s steel structure from collapsing for up to two hours, meeting required fire rating levels (FRLs) and allowing for safe evacuation of the building. This also gives firefighters more time to bring the situation under control.
One of the benefits of intumescent coatings is that they can achieve the necessary FRLs without the need for other fireproofing materials like concrete, vermiculite or fire-rated boards. This can save costs and allow steel components to be incorporated into a building’s design as architectural features.
In addition to its fire-resistant properties, intumescent paint can also protect steel substrates from deterioration and collapse, which can occur at temperatures above 300°C.
By reacting at lower temperatures intumescent paint can help prevent this structural damage and increase the safety of both buildings and the people who respond to emergencies within them.
What Is Dry Film Thickness (DFT) Of Intumescent Paints?
Intumescent paint is a type of coating that can be applied to structural steel to increase its fire resistance. This type of paint works by swelling up, or “intumescing,” when exposed to high temperatures, creating a protective layer of foam that insulates the steel from the heat.
The foam layer can also serve as a barrier to prevent oxygen from reaching the steel, further slowing down the spread of fire.
The effectiveness of intumescent paint depends on several factors, including the dry film thickness (DFT) of the coating. The DFT is the thickness of the paint once it has dried, and it is typically measured in microns.
The required DFT for a certain fire resistance time (such as 30, 60, 90, or 120 minutes) depends on various factors, such as the mass factor, the exposure of the steel to fire, the critical temperature of the steel, and the level of protection required.
The mass factor is a ratio between the area of the steel exposed to the fire and the volume of the steel section, and it affects how quickly the steel heats up. The higher the mass factor the greater the thickness of fire protection material required.
The exposure of the steel to fire is also a factor, as different types of steel elements (such as columns, beams or hollow sections) require different thicknesses of intumescent paint.
The critical temperature is the limiting temperature at which the steel will lose its structural integrity and it varies depending on the degree of utilization. The lower the critical temperature, the greater the thickness of fire protection material required.
The required DFT also depends on the level of protection required which is determined by the fire rating. Different test standards and approvals also give different thicknesses for the same level of protection.
Overall, the dry film thickness of intumescent paint for structural steel is a complex calculation that takes into account a range of factors to ensure adequate fire protection.
How Long Does Intumescent Paint Last?
The effectiveness of intumescent coatings depends on correct application and regular maintenance. If used correctly, they can provide an essential line of defense against fire damage.
The level of protection provided by intumescent coatings can vary depending on the specific type of coating used, with some providing protection for 30, 60, 90 or even 120 minutes.
Intumescent coatings are an attractive option for providing passive fire protection in structures. They offer a sleek and attractive finish that requires no additional protection and are effective in situations that require high levels of fire protection.
When applied and maintained correctly, they provide an essential line of defense against fire damage and offer time for occupants to evacuate safely.
Where Are Intumescent Paints Used For Passive Fire Protection?
Intumescent coatings, also known as intumescent paint, are commonly used for passive fire protection in buildings. These coatings are applied to various load-bearing elements of the building to improve their fire ratings and prevent collapse during a fire. The three most common uses of intumescent coatings are for steel, timber and plaster.
When it comes to steel constructions, intumescent paint can be applied to structural steel members and cast iron to protect them from fire. This is important because structural steel loses its integrity when exposed to temperatures above 550 degrees, which is easily reached during a large fire.
By applying intumescent paint to the steel, the fire protection system can offer up to 60 minutes of fire protection, allowing people to escape before the building collapses. This is necessary to meet building regulations and codes.
Similarly, intumescent paint can also be used to increase the fire performance of timber. Timber has a natural tendency to burn quickly, but thin film intumescent coatings can be used to protect its integrity and offer an additional 30 to 60 minutes of fire protection.
This is important for meeting high standards in fire resistance and improving the structural elements of buildings.
Plaster walls and ceilings also have a natural fire resistance time of up to 20 minutes. However, by applying intumescent paint to the plaster, the fire rating and fire performance can be improved, extending the resistance time to up to 60 minutes.
This is particularly important for lath and plaster ceilings, which are common in almost every building.
In summary, intumescent coatings are an essential component of passive fire protection in buildings. They can be used to protect load-bearing elements such as steel, timber, and plaster from fire and improve their fire ratings and load-bearing capabilities.
By using intumescent paint, buildings can meet important fire test standards comply with building regulations and codes and ultimately provide a safer environment for occupants.
Where Do You Apply Intumescent Paint?
Intumescent paint is a type of paint that swells up when it comes into contact with fire. This swelling action creates a layer of insulation that protects the underlying material from the heat of the fire. Intumescent paint can be applied directly onto the surface of timber structures, either by brush, roller or spray.
There are several varieties of clear intumescent paint that can be used on wood in order to preserve their appearance.