Steel is, perhaps, the most critical designing, engineering and construction material in the world. This article presents a comprehensive overview of the importance of protecting steel to ensure it maintains its structural strength in the event of a building fire.

The protection of steel, a need for greener building options and more radical architectural designs mean the building and engineering sector has progressively embraced the utilisation of thin film intumescent coatings, designed for the specific purpose of safeguarding the structural elements in the case of fire, and also lending to the appearance in exposed steel applications.

Traditionally, low-density fibre or cementitious compounds were used to protect structural steel. When sprayed on steel, this coating type provides heat resistance and can be applied relatively easily by designated applicators. The approved thickness is determined by the type, thickness and purpose of the steel as dictated by building and construction codes, with the sprays divided into wet or dry materials thickness gauges.

Under normal circumstances, the coatings are inert but when they are subjected to extreme temperatures such as a building fire, they undergo a chemical reaction and expand significantly as compared to the original thickness. They then develop a thick char to provide superior fire resistance by creating a buffer between the fire and the steel members, before the temperatures become adequately hot to affect the integrity of the steel.

The new breed of intumescent coatings

While low-density fibre or cementitious compounds represent the old guard of steel fire protection, thin-film intumescents (such as Aithon for timber and Nullifire for steel) are the new guard with the newer technologies offering multiple advantages in fire protection.

Intumescent coatings do not adjust the characteristic properties of materials, for instance, the mechanical properties; are easily processed and handled; and can be applied on-site or off-site, providing increased options to building timelines. Additionally, different kinds of intumescent paint can be utilised on an assortment of construction materials, for example, steel, wood, composites and concrete.

Intumescents are also an excellent solution when aesthetics are an integral factor, especially with steel that is exposed and visible. These coatings are applied much the same way as paint by trained professionals, with each layer adding to the general thickness of the product, and thus, the fire protection capabilities.

Lightweight steel walls and fire protection

In the construction industry, light steel is commonly used for frame walls in mostly non-load bearing applications. Made with studs and tracks, these light steel framed walls often abut to structural load-bearing elements. In this instance, many builders look to use cementitious fire boards to protect the structure. However, a suitable option would be to consider Nullifire SC902 where the steel has been galvanised. Plasterboard sheeting can then be used over the top for the finish.

Fire protection for the oil industry

Though Permax does not offer fire protection options for the petrochemical industry, this important segment needs to be covered as part of the steel protection scope. Petrochemical industries handle oil-based chemicals that burn much faster at much higher temperatures than traditional cellulosic (typical house and building fires), making the need to protect the steel more important than ever so as to ensure crews working in the factory (or on the oil rig) can safely evacuate without fear of the structure tumbling around them.

Epoxy coatings have been utilised effectively for quite a long time to give corrosion protection and fire protection in challenging environmental conditions, typically offshore applications and the petrochemical industry onshore. When carefully applied and rigorously maintained, suitable protection can be achieved for 25 years or more. Such coatings that combine strength/durability, corrosion resistance and fire protection have prompted the wide use of fire resistant applications in the petrochemical, offshore and marine industry.
Overall, due to continued improvement in formulation, application and performance, intumescent coatings have become more accepted, and are more commonly used in recent years and likely to only increase in use in future. This is because thin-film intumescents not only provide fire protection, but also offer a variety of versatile, durable, attractive, low thickness and low weight coatings for a wide variety of structures. 

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