What is Intumescent Paint?
09 September 2022
Also known as intumescent coating, intumescent paint is an effective way of protecting large load-bearing structures from the harsh consequences of enduring a fire.
If you want to buy steel online, it's always important to consider the types of finish you’ll want applied so your steel fabricator can suit your requirements.
We recommend intumescent paint to protect your steel beams, steel columns and other load-bearing steel structures from losing structural integrity in the event of a fire. Intumescent coating is a form of passive fire protection that increases the time for those inside the building to escape in the unlikelihood that a fire occurs. This is vital as it can mean the difference between life and death.
Why Intumescent Paint Is Essential for Fire Protection
Protecting steel using intumescent paint is a great idea as it slows and prevents the steel from reaching a critical temperature during a fire. If steel reaches this critical point, its structural integrity will be greatly harmed, leading to possible collapse or serious damage to the building, putting lives at risk.
The critical temperature of steel is between 350°C and 750°C. This depends on the loading scheme, as steel with higher loads will lose structural stability at a higher temperature. In the majority of use cases, steel will begin to lose its structural integrity at 500°C to 620°C. The passive fire protection provided by intumescent paints is a surefire way to make your buildings much safer than if their load-bearing structures were unprotected from fire.
How Intumescent Paint Protects Structural Steel
Intumescent paints are a paint-like material that, whilst inert at low temperatures, reacts with heat at over 200°C, swelling to form a char layer that covers the steel. The char layer formed has very low thermal conductivity, producing an insulating effect which protects the steel from structural damage by slowing the rate at which the fire will heat it up. It’s important to note that intumescent paints will often swell up to 50 times their original thickness, so for every 1mm of paint applied to your steel beams and columns, you would get 50mm of char layer in the unlikely event of a fire; these thicknesses are frequently referred to as dry film thickness and wet film thickness respectively.
Types of Intumescent Coatings
There are two types of intumescent coating available; these are either thin film or thick film. Thin film intumescent paint is primarily used in domestic and commercial buildings as a method of fire protection. In contrast, thick film intumescent coatings are used in the oil and gas industry to provide much greater protection from even higher temperatures, like those caused by gas or oil fires. They are epoxy-based coatings and typically only swell at five times their original thickness during a fire, although they have a significantly increased dry film thickness.
On-site and off-site application / Composition
Intumescent coatings are a flexible solution for fire protection, with the ability to be applied both on and off-site. This flexibility has led to an increase in its market share as a fire protection system. A huge benefit to applying intumescent paint offsite is that it can be extremely cost-effective. The steel will arrive at your site with fire protection already added, ready to install immediately.
However, it should be noted that off-site application of an intumescent coating is primarily suited for steel that doesn’t require an aesthetic finish. When steel is coated on-site, bolts and damages caused in transportation can be covered, whilst it would be hard to create an identical finish with an off-site application.
Primed and Galvanised Structural Steel
In many cases, steel may require a primer first to ready it for a smooth application of the intumescent paint. Similarly, this approach, along with a thorough degreasing, allows you to use intumescent paints and coatings to provide increased fire protection to your galvanised steel components.
Order Steel Online Using Buy a Beam
To browse a wide selection of steel beams, steel columns and other structural steel components designed to suit any project, and with a wide range of coating and finishes, please visit Buy a Beam’s online shop.