What does fire resistance mean?
Fire resistance refers to a material's ability to withstand fire exposure—including heat, flames, and smoke—for a specified period of time without failing.
Fire resistance refers to a material's ability to withstand fire exposure—including heat, flames, and smoke—for a specified period of time without failing. It is a measured performance characteristic, not a guarantee that the material won't be affected by fire, but rather that it will slow down its spread through walls and floors by maintaining its integrity under fire conditions for a specific duration.
Key Components of Fire Resistance
- Structural integrity: The assembly retains its shape and strength during fire exposure.
- Thermal insulation: The ability to resist heat transfer from the exposed to unexposed side.
- Flame penetration resistance: Delays fire breaching the material or assembly.
- Smoke development: Indicates how much smoke the material produces when exposed to fire.
Time Ratings (ASTM E119 or UL 263)
Fire resistance is often expressed as a time rating, such as:
- 1-hour fire-rated wall
- 2-hour fire-rated floor-ceiling system
These ratings mean the system can withstand fire conditions for that duration without structural failure, flame passage, or excessive heat transfer.
Fire-Resistant vs. Non-Combustible
- Fire-resistant: Resists burning and heat for a time (e.g., MgO board in a 1-hour wall)
- Non-combustible: Will not contribute fuel to a fire (e.g., ASTM E136-rated materials like MAXTERRA structural sheathing products)
Related Testing Standards
- ASTM E119 / UL 263 – Fire resistance of building assemblies
- ASTM E84 – Flame spread and smoke development
- ASTM E136 – Non-combustibility of individual materials