For modern construction, steel offers unmatched strength, but its vulnerability to high temperatures requires innovative fire protection solutions, says Rohit Prabhakar, Business Development Manager of the Mechanical Division at the Uralungal Labour Contract Co-operative Society.

 The average distance between the Sun and Earth is about 150 million kilometers, and light takes approximately 8 minutes and 20 seconds to reach Earth at a speed of 299,792 km/sec. By comparison, the highest speed recorded for human travel was approximately 39,897 km/h, achieved during Apollo 10’s atmospheric re-entry in 1969. While speed has fascinated humanity, it becomes a grave concern during catastrophic events, where the rapid spread of fire or impact can have devastating consequences.

For instance, flames in gas explosions can travel at speeds ranging from 100 m/s to supersonic levels (343 m/s or higher), while wildfires spread more slowly—typically 1.6–9.7 km/h in forests and up to 22.5 km/h in grasslands under high winds. Such events demonstrate how quickly destruction can unfold, emphasizing the need for fire-resistant materials and infrastructure.

The Chicxulub impactor, a massive asteroid or comet believed to have caused the extinction of the dinosaurs 66 million years ago, struck Earth at an estimated speed of 12 to 16 km/sec. This extraordinary speed, combined with the impactor’s size (10–15 km in diameter), released energy equivalent to 100 million megatons of TNT, far surpassing any man-made explosion. The impact created the Chicxulub crater in present-day Mexico, triggering catastrophic global climate changes, including wildfires, tsunamis, and a nuclear winter due to debris blocking sunlight. While this may sound like a tale, the estimated figures are based on scientific evidence.

In modern times, the threat of urban fires is significant. Building fires typically spread much slower than wildfires, with rates varying depending on materials and ventilation. Under typical conditions, a fire can double in size every 30–60 seconds. Urban fires pose a serious risk in densely populated areas, where the proximity of buildings and flammable materials accelerates fire spread. Traditional structures, often made of wood and other combustible materials, are particularly vulnerable. Poor fireproofing, inadequate fire protection systems, and high population density exacerbate this risk. Steel structures, emerging as a reliable alternative, offer durability and adaptability. However, steel is not inherently fireproof—it loses strength at high temperatures (above 550°C). With advanced fire protection systems and thoughtful design, steel structures provide a safer, more sustainable solution for modern urban landscapes.

Steel buildings and Pre-Engineered Steel Buildings (or PEBs) face challenges that are often misunderstood, such as the misconception that steel buildings are not fire-resistant. In reality, steel is naturally non-combustible; however, it loses its structural strength at high temperatures. Steel buildings can be made fire-resistant by applying fireproof coatings, cladding with fire-resistant materials, or using fire-resistant insulation. These methods are examples of passive fire protection (PFP).

Passive fire protection refers to design and construction elements that prevent the spread of fire or reduce its impact without relying on active systems like hydrants, sprinklers or alarms. In the case of steel buildings, passive fire protection focuses on making the structure itself more resistant to fire. This can involve using materials that withstand high temperatures or applying treatments to the steel that protect it from heat. These measures help maintain the integrity of the steel structure in the event of a fire, slowing the temperature rise and preventing the steel from losing its strength too quickly, thereby increasing safety during a fire.

Both active and passive fire protection systems can be installed to enhance the fire rating of a building, whether it's a standard building, steel building, or steel structure. Active Fire Protection (AFP) systems engage to suppress or extinguish a fire, while Passive Fire Protection (PFP) helps resist initial ignition or prevent the fire from spreading. Together, they work to alert occupants, confine the fire, and enable suppression efforts or safe evacuation.

In most buildings, active fire protection systems commonly include water-based fire sprinklers, foam-based systems, portable fire extinguishers, and fire hydrants. However, the effectiveness of Passive Fire Protection (PFP) is often less well-known.

The Heat is On: Protecting Steel Structures from Fire

For steel structures, the key question when selecting a fire protection system is how to maintain the temperature of steel within a specified limit for a certain period. This limit is often referred to as the critical temperature. In the event of a fire, the load-bearing capacity of steel structures is preserved and deformations are minimized when the steel temperature does not exceed this critical threshold. Therefore, the fire resistance capacity of the material, often called the fire rating, is a crucial consideration in design. Fire ratings classify materials based on their ability to resist fire for a specified time, typically expressed in classes such as 30, 60, 90, 120, 180, 240 minutes, or 2, 4, 6, 8 hours. The goal is to contain the fire within a confined space, ensuring that the materials within the space can withstand the rising temperature, heat, and smoke without failure. The recommended fire rating of a building, as per the National Building Code of India (NBC), varies based on the building type, occupancy classification, and height. However, in general, structural elements such as columns, beams, and floors are required to have a minimum fire rating of 90-120 minutes. The concept is simple: within this time, either the fire-fighting team must act, or the occupants must evacuate the building.

Now, the question is: how can steel withstand this rising temperature and if it is possible. The answer is yes, and this is achieved effectively in every steel structure through Passive Fire Protection (PFP) methods. Today, various solutions are available for fire protection of steel structures, and selecting the right system is critical.

Let’s explore a few common PFP materials used to protect structural steel:

1. Intumescent Coatings: These are considered one of the lightest and most effective Passive Fire Protection (PFP) solutions for structural steel. These fire-resistant paints are applied directly to the steel surface and are designed to expand when exposed to heat. At high temperatures, they rapidly expand (up to 100 times their original thickness), creating a thick, stable, insulating layer that protects the steel from the intense heat of a fire. These epoxy-based, paint-like coatings may be on the more expensive side, but they are widely used in commercial, industrial, and residential applications where both fire safety and visual appearance are important considerations.

2. Cementitious Fireproofing: It involves applying a thick layer of fire-resistant materials made from compounds like gypsum, perlite, or vermiculite. These materials, often sprayed or applied as boards, are highly effective at absorbing heat and preventing it from reaching the steel. They form a barrier around the steel, and during a fire, they release water vapor, which helps cool the steel and reduce the rate of heat transfer, thereby delaying the onset of structural failure. This method is comparatively cost-effective and provides a high level of protection.

3. Encasement: Fire-resistant claddings or Mineral Fibre Board materials like calcium silicate or rock wool, form an excellent covering or a protective panel for structural steel components, providing a physical barrier between the fire and the steel, significantly enhancing the fire resistance of the structure. They are designed to absorb heat and maintain their integrity under extreme conditions, protecting the steel from the damaging effects of fire. Relatively easy to install, these claddings are non-combustible, and offer good insulation properties.

4. Fire-Resistant Paints: These are specially formulated coatings that provide a protective layer on structural steel. These paints contain fire-resistant compounds that increase the steel’s fire rating, helping to prevent heat from weakening the material. They do not expand or react to heat and are applied in thinner layers compared to intumescent coatings. They are easy to apply, relatively inexpensive, and provide a sleek, smooth finish.

5. Spray-applied Fire-Resistive Materials (SFRMs): These materials are primarily composed of binding agents such as cement or gypsum and often contain other materials such as mineral wool, quartz, perlite, bauxite, or vermiculite. They are typically sprayed, but some can also be trowel-applied onto the steel surface to provide a protective layer that resists heat. The layer acts as an insulating barrier, preventing heat from reaching the steel and delaying its failure during a fire. They are quick to apply and can cover large areas in a short amount of time.

6. Thermal Wraps or Blanket Systems: These are wraps made of materials with high thermal resistance and relatively low thermal conductivity, which slows the transmission of heat to the underlying structural steel. These fiberglass wraps are impregnated with fire-resistant chemicals and can be wrapped around steel columns or beams. These PFP methods are effective in ensuring that steel structures can withstand fire and maintain their integrity during emergencies. They can be used in retrofit projects or for protecting steel elements in buildings that require fire protection without major alterations to the structure.

Reshaping India’s Landscape: Steel as a Catalyst for Progress

Steel buildings provide an innovative and practical solution to the evolving needs of architects and the construction industry. Unlike conventional materials, steel allows for designs that are both bold and functional. Its strength and flexibility enable architects to create open, expansive spaces without the need for internal columns, offering the freedom to design adaptable floor plans that can evolve with changing needs. This makes steel particularly well-suited for high-rise buildings, modern commercial spaces, sustainable institutional buildings and unique architectural projects that push the boundaries of traditional construction.

When compared to traditional methods, steel construction stands out for its efficiency in both time and cost. The use of pre-fabricated steel components means that construction can proceed faster, with factory precision and consistency in quality, fewer delays and lower labor costs. Steel’s inherent durability ensures that buildings can withstand harsh weather, seismic events, and fires, reducing the need for constant maintenance and increasing their long-term resilience. However, these advantages often go unnoticed, especially in regions where traditional materials like concrete and brick are still the norm.

Besides, steel offers great value for investors as compared to traditional construction methods - not just through its durability and faster build times, but also because even decades later, its scrap value ensures a strong return on investment (ROI).

That said, the full potential of steel in construction is still largely untapped, especially in developing countries like ours. The industry has yet to embrace its full capacity for sustainable development. Steel’s recyclability, energy efficiency, and the integration of modern fire safety and insulation systems make it an environmentally friendly choice for the future. As the demand for faster, more sustainable construction continues to rise, steel buildings have the power to reshape urban landscapes, creating lasting, resilient structures that meet both present and future needs while minimizing environmental impact.

India's capital expenditure for FY 2024-25 includes a historic allocation of ₹11.11 lakh crore, reflecting a major increase from the previous year.. A significant portion of this is directed toward infrastructure development, with a strong emphasis on enhancing physical and logistics infrastructure.

Vision India 2047, also known as Viksit Bharat 2047, outlines the roadmap for India's centenary year of independence. It aims to transform India into a developed nation by 2047 and position the country as a global powerhouse. Infrastructure development is a critical pillar of this vision, recognizing its role as a catalyst for economic growth, social equity, and environmental sustainability.

The plan emphasizes transformative changes across urban and rural infrastructure to meet the aspirations of a 1.7 billion-strong population by 2047. Steel building construction technology is uniquely positioned to leverage this massive opportunity. Its advantages - speed of construction, cost efficiency, and sustainability, align perfectly with the growing demand for urban housing, industrial parks, and transport infrastructure.

With the government's focus on time-bound, resilient, and green infrastructure development, steel structures can address the need for modular, disaster-resistant, and recyclable construction solutions. These qualities make steel construction not just a beneficiary but a critical enabler of India's infrastructure vision.

A Fire-Safe Future: Building Resilience

Transforming infrastructure with steel solutions opens wide opportunities for paving the path to the nation’s future. A comprehensive fire protection strategy for steel buildings involves both 'passive' and 'active' measures. For passive fire protection, it is essential to carefully consider design, building code specifications, and application to ensure the intended fire safety is achieved. Poor application may result in undesirable finishes, added remediation costs, and uncertain fire performance. As with all fire protection products, it is crucial that they comply with the relevant building codes - this requires expert judgment. Incorrect material choices or improper application methods have, in some cases, led to structural failure. The technology itself is not to blame - rather, selecting the right professionals is key.

While misconceptions about steel buildings persist, providing clear information and education can help clients, developers, and architects understand the advantages. By presenting accurate facts and proven success, the adoption of steel solutions can be more confidently embraced.