MGO Board Fire Resistance Official Ratings
Magnesium Oxide (MgO) boards are officially rated for fire resistance using various international standards that categorize their non-combustibility and the fire-resistance duration of the assembly they are part of.
Here are the key official ratings and standards for MgO boards:
Reaction to Fire Classification (Non-Combustibility)
This classification determines if the material itself will contribute fuel to a fire, and MgO boards consistently achieve the highest possible ratings.2
| Standard | Rating/Classification | Description |
| European Standard | Euroclass A1 | The highest classification, meaning the material is non-combustible and will not significantly contribute to a fire. This is often cited as the top level of fire safety. (Tested per EN 13501-1) |
| ASTM Standard (US) | ASTM E136 (Non-Combustible) | This is the standard test method for determining a material’s non-combustibility when exposed to fire. MgO boards pass this test, confirming they do not burn. |
| ASTM Standard (US) | ASTM E84 / UL 723 Class A | This test measures surface burning characteristics, specifically Flame Spread Index (FSI) and Smoke Developed Index (SDI). MgO boards typically achieve a perfect 0/0 rating (Zero Flame Spread, Zero Smoke Developed), which is the best possible result and places them in the Class A (or Class 1) fire rating. |
Fire Resistance Duration (Fire-Rated Assemblies)
This rating measures how long an entire building assembly (like a wall or ceiling) built with the material can withstand fire exposure, maintaining its integrity and insulation.3
| Standard | Rating | Description |
| ASTM E119 / ANSI-UL 263 | 1-Hour, 2-Hour, (or up to) 4-Hour Ratings | This is the standard test for fire-resistance ratings of building construction and materials. It subjects complete wall or floor assemblies to a standardized fire. High-quality MgO board assemblies can achieve 1-hour, 2-hour, and even 4-hour fire ratings, often with less material or without the tapes and sealants required by traditional materials like gypsum. |
Key Performance Highlights of MgO Boards
- Non-Combustible: MgO boards are fundamentally non-combustible.4
- High Temperature Resistance: They can withstand extreme temperatures, often up to 1400 ℉（800℃）or higher, without losing shape or strength.7
- Low Smoke and Toxicity: In fire tests, MgO boards show minimal to zero smoke and do not release toxic gases, which is a major factor in occupant safety.
OCT
2025