Concrete Block Fire Walls

 Risking the investment in a building on less quality flamable materials can result in the disaster in the adjacent photo. Notice the concrete block stair tower is all that remains of this four story apartment fire. This newly constructed apartment was reduced to ashes as well as damaging most adjoining buildings. Masonry contains fire and prevents the spread because it doesn’t burn. Masonry walls can reduce or eliminate the spread of fire and provides precious additional protection and time for occupants to exit or ride out a fire. Everyone should be aware of fire safety and demand redundancy for fire safe construction. Sprinklers provide a form of redunduncy but not in any way a barrier to fire like concrete masonry can.

A PDF of this article is available on the Resource page.

 A very long and tall wall (this is one of three total) in this new construction utilizes 10” x 8” x 16” 3 hour rated cmu’s. The engineer for this manufacturing facility for Mercedes near Tuscaloosa specified these fire walls in concrete masonry. DIV2-4 was selected to supply the project of 50,000 cmu’s. Notable is that the metal structure will be constructed after most of these cmu’s have been installed. The chart below will guide the specifier to the size of cmu required to achieve fire protection. 

 The International Building Code allows for a “blended” computation of fire resistance in hours as shown in the adjoining chart. Light weight block have the same ASTM characteristics as Normal and Medium Weight block yet have better fire ratings by far than either of the heavier choices. That is because when computing the fire resistance the lightweight aggregate gets better marks for resistance than the stone or sand aggregates that are primarily used in Normal and Medium Weight versions.  DIV 2-4 has testing available for review.