Fire resistant coating for steel

fire resistant coating for steel slows down burning of the roof

Why fire resistant coating for steel is necessary

Strength is one of the main reasons we use steel in building construction. Steel is a tough and strong construction material, used in buildings across Canada. 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 temperature of 550ºC, at which point it loses its capacity to bear heavy loads, leading to structural collapse. In fact, strength loss starts already at 300ºC, which is why you need fire resistant coating for steel.

Fire protection 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 fireproof paint for steel, how to comply with building fireproofing regulations, and where to find fire resistant coating for steel products and contractors in Canada.

The 2 types of fire protection paint for steel structures

Anti fire paint for metal 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 find more information on this subject in our general passive fire protection article.

Fire resistant coating for steel stairs damps flames and insulates steel.

Fire resistant coating for steel structures damps flames and insulates steel.

  1. Fire retardant paint: A fire retardant paint works by releasing flame-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. Therefore, this flame resistant paint for metal is usually a topcoat on another anti fire paint.
  2. 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 prolonging the time before it reaches the temperatures that would compromise it. Intumescent paint is the main coating used for steel fire protection.

For the most effective 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.

Application of fire resistant paint for steel: thin & thick film

Fireproofing coatings can be divided into two broad groups: thin film and thick film coatings. Thin film materials are either solvent based or water based and are mainly used for preventing fires in building. Thick film coatings were originally developed for the off-shore and hydrocarbon industries but have been modified for use in buildings.

Thick film fire resistant coating for steel

Thick films 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 optimally. 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.

Thin film fireproof paint for steel

Thin film fire resistant coating for steel systems generally have three components, a primer, a basecoat, 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 1 mm 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.

Understanding the Canadian regulations for steel fire protection

In Canada, most of the building codes rely on the fireproofing regulations according to National Fire Protection Administration (NFPA) which classifies construction materials (including paints) by the rate of flame spread. The classes defined by the NFPA range from A to E, where Class A indicates the lowest flame spread rating. Class D and E materials are not considered suitable for fire protection due to their nonexistent resistance to fire exposure.

  • Class A | flame spread rating 0-25 | excellent fire resistance
  • Class B | flame spread rating 26-75 | moderate fire resistance
  • Class C | flame spread rating 76-200 | light fire resistance

The decision whether to meet Class A, B or C classification is usually determined by your Building Regulations Officer or Architect.

Once your coating is applied, you should obtain a certificate to show that your building  complies with all relevant regulations and that the correct protective surface coating is used. If you do not obtain the correct certificate(s) then, in the event of a fire, you may be held liable and prosecuted.

Find fire resistant coating for steel products and services in Canada

There are many fireproof paint for steel products available on the Canadian market. AkzoNobel, Jotun, Bollom, and Thermoguard all have anti fire ranges. The price and coverage of these coatings are dependent on the degree of fire resistance and film thickness; additionally, correct application contributes to the costs. If you would like any more information regarding fire protection for 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.

 


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