Construction materials and fire safety: How combustibility affects fire risk

Why construction materials matter for fire safety

When a fire starts, building materials play a major role in how quickly flames spread, how severe damage becomes, and how likely a structure is to experience a partial or total loss. Some materials ignite easily and add fuel to a fire. Others resist heat and slow fire growth – buying critical time for evacuation, fire protection systems, and recovery. Construction material selection is not just a design decision. It directly influences employee safety, property damage, and operational continuity during and after a fire.

How building materials influence fire behavior

Building materials shape how a fire develops inside a structure. Materials that ignite easily can accelerate fire spread and increase damage, while fire resistant materials help slow fire growth and limit loss.

• Slow the spread of fire
• Reduce structural damage
• Improve occupant safety
• Support faster recovery after a loss

Understanding combustibility in buildings

Not all building materials perform the same way in a fire. Understanding the difference between combustible and fire-resistant materials helps explain why some fires grow rapidly while others are contained.

Combustible materials

Combustible materials can ignite, burn, and intensify a fire. Once ignited, they release heat that increases fire size and makes fires more difficult to control.

• Solid wood and engineered wood products, including laminated beams, trusses, and mass timber components
• Plastic tanks, piping, panels, and totes
• Foam or other combustible insulation
• Certain wall and ceiling finishes
• Packaging, pallets, and stored products

Fire-resistant materials

Fire resistant (or noncombustible) materials resist ignition and slow the movement of heat and flame through a structure. These materials buy time – time for evacuation and for fire protection systems to work.

• Concrete and masonry
• Brick and stone
• Gypsum board (installed correctly)
• Fire rated steel assemblies
• Fire rated roofing systems

Using materials as they’re intended

Fire performance doesn’t just depend on what a product is made of – it also depends on how and where it’s used. Materials that perform well in one setting can become a serious fire hazard if they’re installed outside their intended or listed use. Examples include residential-grade doors in repair shops, decorative wall panels in washdown areas, or metal skin installed over exposed foam insulation. When selecting or replacing materials, verify that products are rated and approved for the way they’ll actually be used in your facility.

How construction type affects fire behavior and potential loss

While individual materials matter, how those materials are assembled into a building matters just as much. That’s where construction type comes in. Construction type is a fire protection classification used by insurers and fire professionals to understand how a structure is likely to react in a fire. These classifications help anticipate how a building may perform during a fire and how likely it is to experience severe damage or total loss. In simple terms: The more combustible the structure, the faster a fire can spread and the higher the likelihood of severe damage or total loss.

Common construction types and fire performance

Construction type influences how quickly fire spreads, how much damage occurs, and how likely a total loss may be. The following categories describe typical fire performance characteristics and are provided for general understanding rather than formal code classification.^6,7

What if you can’t change your construction type?

• Improved housekeeping practices
• Effective fire protection systems
• Isolate high hazard areas
• Clear operational controls and employee training
• Avoiding “off-label” substitutions: Use building materials and assemblies only in ways that match their fire rating and manufacturer’s intended use.
• Separate or limit storage to daily use amounts in key areas

These measures help existing buildings behave more like fire-resistant structures, even when the original construction type cannot be changed.

Why construction materials and building type matter to operations

• How fast a fire can grow
• How likely structural collapse is
• How severe damage may be
• How quickly operations can recover

Facilities built with more fire resistant materials and construction often experience slower fire development, less structural damage, and reduced business interruption.

Key takeaway: Reducing fire risk through material and construction choices

Fire safety goes beyond minimum code requirements. Construction material and building type decisions directly affect employee safety, property damage, and recovery after a loss. Considering fire resistance during construction or renovation strengthens long term operational resilience.

Quick summary for facility and operations leaders

Construction materials and building type influence how fires grow, how much damage occurs, and how quickly operations recover. Fire resistant materials and assemblies slow fire development, reduce total loss potential, and support safer outcomes during fire events.

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