Enhancing Fire Safety in steel Structures:

The Role of Reactive paints and Comprehnsive testing Standards

Reactive paints, also known as intumescent coatings, are essential in enhancing the fire resistance of steel structures in buildings. Engineered to respond when exposed to high temperatures, these coatings expand and form an insulating barrier that slows down heat transfer, protecting the steel beneath. By delaying the point at which criticalt

Fig-1 Short columns under resistance to fire at Afiti Global Fire Testing Private Limited.

emperatures are reached, reactive paints provide valuable time for evacuation and firefighting, significantly contributing to overall building safety. This approach is especially crucial in high-rise and public buildings , where preserving the structural integrity during a fire is vital to safeguard lives and reduce damage.

Testing Reactive Paints for Fire Insulation

The effectiveness of reactive paints in fire insulation is rigorously tested to meet safety standards. One such test follows the British Standard BS 476 Part 20, which provides guidelines for fire-resistance testing of construction materials. This standard evaluates how well the reactive paint insulates structural steel columns, thus ensuring that the coated columns can withstand high temperatures without reaching failure.

1. Preparation of Specimens : To start, short columns are prepared through surface cleaning and instrumentation. The columns are then coated with reactive paint, which expands and insulates when exposed to fire.

2. Furnace Testing : The columns are placed inside a furnace and subjected to high temperatures according to the standard time-temperature curve specified by BS 476 Part 20. This curve simulates the heat progression typically experienced in a structural fire.

3. Insulation Measurements : Thermocouples installed on the columns monitor the surface and core temperatures of the steel. The critical factor is the paint’s ability to keep the core temperature below a level that could compromise structural integrity, effectively delaying potential failure.

4. Reporting : Test results record the time it takes for the column to reach incremental temperatures of 500°C, 550°C, 600°C, 650°C, 700°C, and 750°C. These readings indicate the paint's effectiveness over time in preventing heat penetration.

Additionally, IS 17044:2018 provides guidelines for testing intumescent fire-retardant paint, particularly water-based types. However, it does not recommend testing using the cellulosic time-temperature curve. Instead, it includes a test to assess flame spread when the paint is applied to wooden panel.

EN 13381-8: A Comprehensive Testing Standard

For a more thorough testing and classification of reactive paints, EN 13381-8 offers a comprehensive standard. It provides detailed criteria and classification requirements for reactive coatings on steel columns, beams, and other structural elements. Applying this standard can help develop a unified approach to testing and certifying reactive paints in India, where a structured guideline is essential to ensure the reliability of fire-resistant coatings.

Fig -2 Long columns and short beams under test as per EN13381-8 at AGFTPL for various DFTs.

Fig3- Comparison of performance of insulation to the standard and smouldering fire curves

Importance of Testing Under Loaded Conditions

While standard time-temperature curve testing provides crucial insights, it doesn’t account for the impact of mechanical loads on fire resistance. Real-world conditions involve structural loads on columns and beams, which can affect how the paint performs during a fire. Testing under these conditions ensures that the paint retains its insulating properties even when the structure is under load.

   

Moreover, conducting a smouldering curve test, which simulates prolonged exposure to low temperatures, is also critical. Reactive paints may react differently at low temperatures compared to high-temperature scenarios, so this test ensures that the paint performs reliably across various fire conditions.

Conclusion

Reactive paints are indispensable for enhancing fire protection in steel structures, particularly in buildings where structural integrity is paramount during a fire. By adhering to testing standards like BS 476 Part 20 – General requirements or ISO834 test procedure and EN 13381-8, the insulation properties of these paints can be rigorously evaluated to ensure reliability. As the mild steel structures are getting good attention in India, adopting these standards will help establish certified testing and improve fire safety in construction. Testing under loaded and low-temperature conditions further enhances this process, guaranteeing that reactive paints deliver consistent protection even in diverse fire scenarios, thus advancing building safety and resilience.