Fire resistant paint for steel and why it’s needed
Strength is one of the main reasons we use steel in building construction. Steel is a tough construction material, used in buildings across the country. However, this strength is challenged by the severe heat of a fire. In a fire, it can take only minutes for unprotected steel to reach critical failure temperatures of 550ºC, at which point it loses its load bearing capacity, leading to structural collapse. In fact, above 300ºC steel begins to lose strength. Which is why you need a fire resistant paint for steel.
Fireproof paint for steel can provide the following advantages:
- Fire protection for up to 120 minutes
- Preventing structural collapse
- Allowing firefighters more time to get the fire under control
- Extending crucial evacuation time
In this article we outline the different types of fire resistant paint for steel, how to comply with building fireproofing regulations, and where to find fireproof paint for steel products and contractors in India.
The 2 types of fireproofing paint for structural steel
Fireproof paint can be classified by fire protection method: intumescent or fire retardant. Each of these coating types are further divided by the length of time they provide fire protection for – 30, 60, 90, or 120 minutes. Building regulations require different minimum time requirements which vary depending on building type. You can read more about this subject in our general passive fire protection article.
- Fire retardant paint: A fire retardant paint works by releasing a fire-damping gas when heated, which prevents the spread of flame across a surface – usually walls and ceilings. It is less common to use fire retardant paints for steel structures, because they do not have the same insulating properties of intumescent paint.
- Intumescent paint: Intumescent paints protect their steel substrate by providing an insulating layer between steel and the fire. Exposure to the heat of a fire triggers a reaction, causing the intumescent paint to expand to up to 50 times its thickness and form a solid foam-like char. This char insulates the steel from the heat, so keeping it below the temperatures that would compromise it. Intumescent paint is the main coating used for steel.
For the most comprehensive fireproof paint system, you can use these two paints together, with fire retardant paint as a top coat over intumescent paint. In this case, the flame retarding action prevents the intumescent paint from triggering, adding vital extra time.
Thin and thick film fire resistant paint for steel
Fire resistant paint for steel can be divided into two broad families: thin film and thick film. Thin film materials are either solvent based or water based and are mainly used for building fires. Thick film coatings were originally developed for the off-shore and hydrocarbon industries but have been modified for use in buildings.
- Thin film fire resistant coatings for steel generally have three components, a primer, a base coat, and a sealer coat. These paints are mainly used for 30, 60, and 90 minutes. Thin film materials have a 50:1 expansion ratio; a 1mm thick coating will expand to about 50mm in a fire. These coatings are both solvent- and water-based, and are available in a range of finishes.
- Thick film coatings have a higher dry film thickness than thin film coatings, and are usually epoxy based. Originally developed for use with hydrocarbon fires, thick film materials are now also used in harsh or difficult to maintain environments where thin film materials would not work. Examples include external steel in high rise buildings and exposed marine environments. Expansion ratios are typically about 5:1, and attractive finishes are also possible.
Fireproofing structures with fire resistant coating for steel in India
There are many fireproof paint for steel products available on the Indian market. AkzoNobel, Jotun, Bollom, and Thermoguard all have intumescent ranges. If you would like any more information regarding fireproofing steel, or would like to be connected with one of our partners for your project, contact us! Our experts are here to help, just use the “Request a quote” button at the bottom of this article and take advantage of our 100% free quote service.