In the vocabulary of modern steel construction, efficiency has long been the dominant language, with optimised sections, lean members, and elegant spans defining the built environment. But fire, as a design condition, rewrites this language entirely. Fire resistance is no longer being viewed as a compliance checkbox, but as a fundamental parameter that influences structural behaviour, cost, detailing, and even architectural intent. Insights from leading practitioners reveal a deeper truth.
FIRE AS A BEHAVIOURAL DISRUPTOR, NOT JUST A LOAD CASE
At ambient conditions, steel behaves predictably. Load paths are defined, material properties are stable, and design assumptions hold firm. Fire dismantles this certainty. As Krishna Prabhu, Senior Manager Design, Nippon Koei India Pvt Ltd explains, failure in fire is rarely just about loss of strength. “It is largely stiffness degradation and instability driven… the modulus of elasticity drops much faster than strength, which means deflections and second-order effects govern earlier than expected.”
This introduces a more complex reality that structures do not simply become weaker; they behave differently. Thermal expansion, restraint forces, and evolving boundary conditions create new internal forces that were never part of the original design envelope.
Rajarajan JR, Chief Engineering Manager, Buildings & Factories, L&T Construction reinforces this shift from a practical standpoint: “Steel loses its yield strength in proportion to the exposed temperature, thus fire coating is inevitable… fire shifts the conversation from efficiency to robustness.” Together, these perspectives underline a fundamental change: fire must be treated not as an external hazard, but as a condition that fundamentally alters structural mechanics.
“Failure in fire is rarely about strength alone, it is driven by stiffness degradation, instability, and a fundamental change in structural behaviour.” — Krishna Prabhu
FROM AFTERTHOUGHT TO EARLY-STAGE INTEGRATION
Traditionally, fireproofing enters the project lifecycle late, after structural optimisation, often during tendering or execution stages. This sequencing, as all three experts indicate, is increasingly proving inefficient. “Fireproofing still enters the conversation after structural optimisation is complete, which is somewhat backwards,” notes Krishna Prabhu, highlighting how this leads to retrofitted compliance rather than integrated performance.
Echoing this, PDP Bhushan, Freelancing Consulting Engineer, stresses the need for early inclusion: “It has to be at the stage of preliminary engineering itself to avoid last minute changes in member sizing and procurement.” From an EPC perspective, Rajarajan JR observes that while fireproofing is typically considered post-schematic design, global practices are pushing for earlier integration, where fire ratings directly influence member selection and architectural decisions.
This convergence signals a clear direction: fire strategy must be embedded at the concept stage, not appended at the end.
When Timing Impacts Cost
- Late-stage fireproofing leads to redesign and procurement delays
- Slender members may require thicker coatings, increasing cost
- Early integration allows balancing steel tonnage vs coating thickness
- Architectural exposure decisions influence fireproofing systems
THE HIDDEN ENGINEERING TRADE-OFF: STEEL VS COATING
One of the most underappreciated aspects of fire design lies in the inverse relationship between section size and coating thickness. As Rajarajan J R explains, “Thickness of fire coating is inversely proportional to the thickness of the structural steel members, an optimised thin member may require higher coating thickness, resulting in higher cost.” This creates a nuanced engineering trade-off. What appears optimal structurally may not be optimal when fire protection is considered.
PDP Bhushan adds another dimension: fireproofing can indirectly increase steel quantities if not integrated early, reinforcing the need for coordinated design. Meanwhile, Krishna Prabhu pushes the discussion further into system behaviour, pointing out that connections, often overlooked, can become critical failure points under fire due to combined thermal and mechanical effects.
The implication is clear: fireproofing is not an accessory—it actively reshapes engineering decisions.
“Fire protection must be treated as a fundamental design parameter, on par with wind and seismic loads.” —PDP Bhushan
MISALIGNMENT BETWEEN SPECIFICATIONS AND STRUCTURAL INTENT
A recurring concern across practitioners is the disconnect between fireproofing specifications and actual structural requirements. “Alignment is more coincidental than intentional,” observes Krishna Prabhu, noting that uniform fire ratings are often applied without distinguishing between primary and secondary members.
Similarly, PDP Bhushan points out that vague client specifications often lead to debates during execution, emphasising the need for early stakeholder consensus.
From a practical standpoint, Rajarajan JR highlights how material choices of cementitious vs intumescent coatings are often driven by exposure and aesthetics, adding layers of cost and execution complexity.
The underlying issue is not lack of standards, but lack of alignment. Codes provide a baseline, but projects demand contextual interpretation.
PERFORMANCE-BASED DESIGN: THE INEVITABLE EVOLUTION
Standard fire ratings, based on uniform heating curves, have long guided fireproofing strategies. But real fires rarely follow such predictable patterns. “Performance-based design is gaining ground because real fires do not follow standard fire curves,” explains Krishna Prabhu, pointing to localised and non-uniform thermal conditions.
Rajarajan JR acknowledges that while adoption is gradual due to complexity and stakeholder acceptance, PBD offers more realistic scenarios and optimised material use. PDP Bhushan reinforces its economic potential, noting that once supported by sufficient experimental validation, it can deliver significant cost efficiency.
Despite slower uptake in India, the trajectory is evident. Complex projects will increasingly demand performance-driven approaches.
Rajarajan JR highlights the proprietary nature of fireproofing systems and the need for early coordination with manufacturers to ensure compatibility and execution clarity. Taking a broader view, PDP Bhushan points out that integration is often missing altogether, with stakeholders working in silos unless guided by a unified approach.
This reinforces a critical insight that fireproofing is as much about collaboration as it is about engineering.
“Fire shifts the conversation from efficiency to robustness.” — Rajaram JR
THE ROAD AHEAD: INTEGRATION, LEADERSHIP, AND SYSTEMS THINKING
Across all three perspectives, a consistent message emerges. The industry must evolve from fragmented decision-making to integrated design leadership. PDP Bhushan calls for fire protection to be treated as a fundamental design parameter, on par with wind and seismic loads, with structural engineers taking a central coordinating role.
Rajarajan JR advocates for BIM integration, early-stage workshops, and mock-ups to bridge gaps between design and execution.
Krishna Prabhu pushes the conversation further toward designing for system behaviour, controlled failure mechanisms, and lifecycle performance rather than one-time compliance.
Together, these viewpoints outline a future where fire design is not an add-on, but a defining force in how steel structures are conceived, detailed, and delivered.
Editor’s Note:
Fire resistance in steel construction is at a decisive inflection point. What was once treated as a protective layer is now emerging as a design driver, reshaping how engineers think about behaviour, how architects approach exposure, and how projects balance cost with performance. As projects grow more ambitious and performance expectations rise, the question is no longer whether steel can withstand fire, but whether the industry is ready to design for it holistically.
