A 60-minute fire-rated wall with magnesium oxide (MgO) board is a partition system that has been tested to withstand exposure to fire for at least one hour while maintaining its structural integrity and insulation. The fire rating of a wall assembly is not determined by the board alone, but by the entire system, including the framing (e.g., steel or wood studs), the number and thickness of the MgO boards, and how the joints are sealed.
How MgO Boards Achieve a 60-Minute Fire Rating
MgO boards are inherently fire-resistant, but their performance in a wall assembly is what earns the official rating. This fire-resistant property comes from several key characteristics:
- Non-Combustibility: MgO boards are classified as non-combustible. They will not burn, contribute fuel to a fire, or release harmful smoke and gases, which is a major advantage over many other materials. They are often rated A1 according to European standards (EN 13501-1) and are certified as non-combustible under standards like ASTM E136.
- High-Temperature Resistance: The melting point of magnesium oxide is extremely high, around . This allows the board to maintain its structural integrity and stability for a long time during a fire.
- Release of Water Vapor: When exposed to intense heat, the magnesium hydroxide within the board releases water vapor. This process, known as dehydration, is endothermic (it absorbs heat), which helps to cool the surface and further slow the spread of the fire.
To achieve a 60-minute rating, a wall assembly typically uses a specific configuration. For example, a single layer of a sufficiently thick MgO board (often 9mm to 12mm or thicker) on each side of a steel or wood stud frame can be sufficient. The specific thickness and number of layers are critical and must be determined by fire test reports.
Benefits in Fire-Rated Walls
Using MgO board for fire-rated walls offers several benefits beyond its fire performance:
- High Impact Resistance: MgO board is very dense and durable, making it more resistant to impact than traditional drywall.
- Moisture and Mold Resistance: It does not absorb water and is naturally resistant to mold and mildew, making it an excellent choice for fire-rated walls in damp environments like kitchens or bathrooms.
- Sound Insulation: The density of the board also gives it good acoustic properties, helping to reduce noise transmission
- Ease of Installation: While dense, the boards can be easily cut and installed using standard tools, similar to working with other panel products
SEP
2025