5 Reasons Why AAC Has a Higher Fire Resistance

Because of its purely mineral composition, AAC has a higher fire resistance and is classified as a non-combustible building material. Autoclaved aerated concrete (AAC) has a 4-hour fire resistance compared to other building materials due to several factors:

1. Cellular structure: AAC has a cellular structure that makes it more resistant to fire. The small air pockets in the material reduce the amount of fuel available for combustion and slow down the spread of fire. Due to the unique cellular bee-hive-like structure, the fire resistance portion of AAC blocks is very high. It has a fire rating of 4 to 5 hours or even higher.

2. Low thermal conductivity: AAC has a low thermal conductivity. Thermal Conductivity of AAC is 0.16 - 0.26 w/mK, which means that it does not conduct heat well. This helps to limit the spread of heat within the material and prevents fire from quickly spreading through the wall or floor system.

3. Mineral Compositions: The main components of AAC, such as cement and lime, have an alkaline nature that makes them resistant to fire. The alkaline nature helps to prevent the formation of flammable gases, which can be produced by the combustion of organic materials.

4. High Thermal insulation: AAC blocks have a high thermal insulation value, which helps to keep the internal temperature of the building low, even in the event of a fire.
   

5. Fireproof coatings: AAC blocks can be coated with fireproofing materials, such as intumescent coatings, to improve their fire resistance. These coatings are designed to expand when exposed to heat, creating an insulating layer that slows down the spread of fire.
   

Summary

In summary, AAC's cellular structure, low thermal conductivity, alkaline nature, and the ability to be coated with fireproofing materials all contribute to its longer fire resistance compared to other building materials.

It is important to note that while AAC provides good fire resistance, proper fire protection measures such as automatic fire sprinklers, fire-rated doors and windows, and fireproofing coatings are necessary to ensure the safety of the building and its occupants in the event of a fire.