One of the most effective forms of passive fire protection is Intumescent Paint – a specialised coating that shields structural elements from the intense heat of a fire. 

When it comes to firestopping a building, there are two primary strategies: active fire protection and passive fire protection. Active fire protection involves systems that require a trigger or an alert to function, such as sprinklers or alarms. On the other hand, passive fire protection focuses on the structural integrity of the building, utilising coatings, claddings, or free-standing systems that provide thermal protection in the event of a fire. 

One of the most effective forms of passive fire protection is Intumescent Paint. This specialised coating expands when exposed to heat, forming a thick, insulating layer that shields structural elements from the intense heat of a fire. 

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What is Intumescent Paint? 

Intumescent paint is one of the most effective and lightweight forms of passive fire protection. It’s a coating that reacts to heat by expanding many times its original thickness—up to 100 times—to form a stable, carbonaceous char. This char layer acts as an insulating barrier, significantly reducing the rate at which heat is transferred to the structural elements of a building, such as steel beams. 

The primary function of this char is to delay the time it takes for the substrate (the material beneath the paint) to reach critical temperatures that could lead to structural failure. Notably, this protective layer must remain intact during any movement in the steel—such as expansion or deflection—until the fire protection criteria have been met. 

Intumescent paints are typically applied using airless spray equipment, which ensures speed and a high-quality finish. However, depending on the brand and project requirements, brush or roller applications may also be employed. To achieve the necessary dry film thickness, which is often required for up to 120 minutes of fire protection, several coatings are usually needed. 

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Types of Intumescent Paint 

1. Water-based Intumescent 

Water-based intumescent coatings are an eco-friendly option with lower chemical emissions and reduced odour compared to other types. They are generally the least expensive and are ideal for environments where temperature and humidity levels are controlled. However, these coatings are less tolerant to humidity and low temperatures, which can extend drying times. 

2. Solvent-based Intumescent 

Solvent-based intumescent coatings are designed for environments where temperature and humidity fluctuate. They are more resistant to weather conditions and tend to dry faster and more consistently than water-based options. Additionally, they offer a smoother finish, making them a popular choice for semi-exposed environments. 

3. Epoxy-based Intumescent 

Epoxy-based intumescent coatings are the go-to choice for harsher environments, such as offshore marine industries or chemical plants. These coatings provide excellent hydrocarbon fire protection and are highly resistant to corrosion. They come as a two-part system that forms a thick and durable film when combined, offering robust protection in extreme conditions. 

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Sentinel’s Expertise in Action 

As London’s most-trusted fire protection sub-contractor, we have a proven track record of delivering technical solutions in the design, supply and installation of complex passive fire protection systems. By placing emphasis on safety, quality, innovation and sustainability, we can constantly adapt fire protection and firestopping solutions to our clients’ evolving requirements. 

Kingston University Townhouse 

We were delighted to provide a full suite of commercial decorating and passive fire protection services throughout the six-storey structure, which was designed by Grafton Architects – winner in 2020 of a RIBA Gold Medal.   

Decorating the Townhouse included the need to treat large expanses of timber paneling, which was a central feature of Grafton Architects’ bold design for the interior of the new structure. This required a firestopping solution that would match untreated and pre-treated timber and could also meet the stringent sustainability requirements at the site. Our team took several measures that enabled them to deliver the required level of passive fire protection while enhancing the natural beauty of the timber panelling used.  

After a careful selection process, we applied intumescent Envirograf paint to all architectural woodwork and panelling. The aim was to deliver a flawless match for the untreated and pre-treated timber. 

As planned, the untreated and pre-treated timber matched flawlessly. The building has since been rated BREEAM Excellent for its many sustainability features. 

Read the full case study here

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The Whittington Building 

We were engaged by Knight Harwood to provide specialist decorating services to a new five-storey development that replaced two buildings owned by the Worshipful Company of Mercers.   

One building was redesigned by architect Stanton Williams as an office building, with an open-plan ceiling exposing all beams, decking and services. The other was assigned to contain the Mercers’ archive rooms across four floors.    

In the section of the new development that was dedicated to office space, Sentinel sprayed the beams with intumescent paint to a decorative finish, then applied a topcoat to both the beams and the metal decking. Our team of specialist decorators used single-leg spray equipment to apply the intumescent Sherwin-Williams FX6010. This is a highly durable coating that dries fast and provides a finish that is both aesthetically pleasing and fire resistant for up to two hours.   

The Whittington Building achieved a rating of Excellent on the BREEAM code, and an EPC A-rating. Performance against Part L Regulation targets – which measure energy usage and carbon emissions – has improved by 47 per cent, while fresh air ventilation is available throughout this all-electric structure.  

Read the full case study here 

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Whether you require a water-based solution for an environmentally sensitive project or a robust epoxy-based coating for an offshore platform, understanding the different types of intumescent paints is crucial for making the right choice. 

At Sentinel Contracting Plc, we bring years of expertise and a proven track record in fire protection to ensure your building is equipped with the best possible defence against fire. With our comprehensive approach, you can rest assured that your project is in capable hands. 

If you’re considering intumescent paint for your next construction project, or if you’d like to learn more about our fire protection services, please don’t hesitate to get in touch.