Fire rating (Dutch: brandwerendheid) is the degree to which a construction element or assembly can withstand fire, expressed as a time in minutes during which it maintains specific performance criteria. It quantifies how long a wall, floor, door, or other element keeps functioning under standardised fire conditions.
How fire rating is determined
A fire rating is established through standardised fire tests in accredited laboratories. The element is exposed to a temperature-time curve (typically ISO 834) while instruments monitor:
- Load-bearing capacity — does the element continue to carry its design load?
- Integrity — do flames or hot gases penetrate to the unexposed side?
- Insulation — does the unexposed surface remain below dangerous temperatures?
The fire rating in minutes is the shortest time at which any of the tested criteria fails.
Fire rating classifications
| Rating | Meaning |
|---|---|
| **EI 30** | Maintains integrity and insulation for 30 minutes |
| **EI 60** | Maintains integrity and insulation for 60 minutes |
| **EW 30** | Maintains integrity and limits radiation for 30 minutes |
| **REI 120** | Maintains load-bearing, integrity, and insulation for 120 minutes |
Fire rating vs. fire resistance
While the terms are often used interchangeably, fire rating typically refers to the classification assigned after testing, whereas fire resistance describes the inherent property of the material or element. In practice, a product receives a fire rating based on demonstrated fire resistance during a fire test.
Application
Fire ratings are essential for specifying fire doors, partition walls, floor slabs, glazing, and service penetrations. Architects and engineers match the required fire rating from building regulations to certified products. Every fire-rated element in a building must be installed according to the tested configuration to maintain its classification.
Related Terms
- Fire resistance
- Fire test
- Fire prevention
- Fire spread
- Fire door
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