How Does Fire Spread?

Fire spreads in ways most people don’t see until it’s too late. In just minutes, a small flame can become a full-scale blaze ripping through buildings and threatening lives. Understanding how this happened isn’t just important, it’s essential to create a safe building. 

There are four primary mechanisms of fire spread: conduction, convection, radiation and direct burning. Each presents unique risks and can undermine well-designed fire safety systems, unless you’ve implemented robust passive fire protection measures. 

Conduction Fire 

Conduction refers to heat moving through solid materials. In buildings, this happens when thermal energy travels through conductive surfaces such as steel beams, metal fixings or even reinforced concrete.

• A key danger of conduction fire is how silently it moves 
• Heat can migrate through structural elements from one room to another, igniting distant materials 
• Areas  far from the ignition point can erupt into flames long after the outbreak 

Passive fire protection blocks this spread by insulating structural steel, sealing wall penetrations and using fire-resistant materials where heat transfer could occur. It’s not enough to contain the flame, you must contain the heat. 

Convection Fire 

Convection fires are fast. It’s the transfer of heat through gases, primarily hot air and smoke. When fire breaks out, it produces rising columns of hot gas that quickly spread upward and outward.  

• Flames push through open voids, ceiling cavities and stairwells at speed 
• Smoke, often more dangerous than the flames, compromises visibility and air quality 
• In multi-storey buildings, fires can climb floors within minutes 

This is why vertical fire-stopping measures are essential. By compartmentalising floor levels and sealing ceiling voids, convection-driven spread can be significantly reduced, buying time for evacuation and emergency response. 

Radiation Fire 

Radiation doesn’t need contact or air movement, it transmits energy through electromagnetic waves. This means flammable items located several metres away from a blaze can ignite simply from exposure to extreme heat. 

• Fires can jump gaps, corridors or even courtyards without direct contact 
• Glass, polished metals and large open-plan areas can intensify radiant heat 
• Adjacent spaces risk becoming ignition points if not shielded properly

Effective passive fire protection includes installing heat-resistant glazing and adding protective shielding. The goal is to prevent heat energy from turning adjacent arenas into fuel. 

Direct Burning 

The most direct method of spread is exactly what it sounds like, one object burning and then igniting the next through contact. It’s common, it’s fast and in cluttered or poorly managed environments, it’s almost unstoppable.

• Clutter, packaging, stockpiles and soft furnishings act as fuel 
• Even fire-resistant buildings can be compromised if combustible materials are unchecked 
• Flame contact quickly turns isolated fires into full-room blazes 

The solution isn’t just spacing. It’s the strategic use of non-combustible finishes, compartmentation and ongoing maintenance. Fire doors, treated materials and layout planning all contribute to preventing this method from overwhelming your defences. 

How Quickly Does Fire Spread? 

It’s not just how, it’s how fast. In a typical modern structure, fire can double in size every 30 to 60 seconds. Within three to five minutes, an entire room can be engulfed. If it breaches structural or vertical pathways, it can move between floors in less than a minute. 

These timeframes leave little margin for error. Passive fire protection doesn’t just contain fire, it slows it. It protects escape routes, preserves building integrity and gives occupants and first responders a fighting chance. 

Built-In Protection from Adaston 

Adaston’s approach to fire protection is proactive. By embedding systems that resist, isolate and delay fire spread, we ensure your building isn’t just compliant, it’s resilient. 

We specialise in: 

• Compartmentation that isolates fire into manageable zones 
• Fire-stopping that seals off voids, penetrations and service routes 
• Advanced passive systems, such as fire doors 

Ready to Stop Fire in Its Tracks? 

Fire doesn’t choose how it spreads. It uses every available path, conduction, convection, radiation and direct burning, to expand. Understanding these paths lets you close them. 

If you’re responsible for a building’s safety, you need more than alarms and sprinklers. You need barriers that stop fire. Get in touch with Adaston to learn more about how to prevent fires in your building.