Blog

A “60/60/60 fire-rated wall” refers to a wall assembly that has been tested and certified to resist fire for at least 60 minutes across three critical performance criteria. This rating is often a requirement in building codes, especially in commercial or multi-family residential structures, to ensure the safety of occupants and limit the spread of fire.

The three criteria in the Fire Resistance Level (FRL) rating are:

1. Structural Adequacy (60): The ability of the wall to withstand a fire and continue to carry its structural load without collapsing for at least 60 minutes. This is especially important for load-bearing walls.
2. Integrity (60): The ability of the wall to remain intact and prevent the passage of flames and hot gases through cracks, gaps, or other openings for at least 60 minutes.
3. Insulation (60): The ability of the wall to limit the temperature rise on the non-fire side to below a specified threshold, preventing the spread of fire through heat transfer and protecting occupants on the safe side for at least 60 minutes.

How MgO Board Contributes to a 60/60/60 Rating

While the rating applies to the entire wall assembly and not just the board itself, Magnesium Oxide (MgO) board is an excellent core component for achieving this level of fire resistance. Its inherent properties make it a superior choice:

• Non-Combustibility: MgO is a mineral-based material that will not burn, contribute fuel to a fire, or produce significant smoke or toxic gases. It is often classified as a non-combustible material under standards like ASTM E136 and EN 13501-1 (Class A1).
• High-Temperature Resistance: The melting point of MgO is extremely high (around 2800∘C), allowing the board to maintain its structural integrity under intense heat for extended periods.
• Endothermic Reaction: When heated, the hydrated compounds within the MgO board release water vapor. This process absorbs heat, effectively cooling the surface and further slowing the temperature rise on the unexposed side of the wall.

Typical 60/60/60 Fire-Rated Wall Assembly with MgO Board

To achieve a 60/60/60 fire rating, the wall is not just a single sheet of MgO board. It is a complete system that has been rigorously tested. A typical assembly would include:

• Framing: Steel or fire-rated timber studs.
• Core Cavity: The space between the studs, often filled with a non-combustible insulation material like mineral wool or rock wool to enhance insulation performance.
• Facing Boards: One or more layers of MgO board, typically 9mm to 12mm thick, installed on both sides of the framing. The specific thickness and number of layers are determined by the fire test report for that particular system.
• Joints and Fasteners: All joints between the boards are taped or sealed with fire-resistant materials, and fire-rated screws are used to fasten the boards to the framing. The type and spacing of fasteners are crucial to maintaining the integrity of the assembly during a fire.

By using MgO board as a key component, manufacturers can design and test wall assemblies that not only meet the demanding 60/60/60 FRL but also provide a durable, moisture-resistant, and sustainable solution for modern buildings.