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Scored Block

Scored block is available with 1, 2, 3, 5 or 7 ribs as illustrated, corner units with ribs on the end, also available. In addition to being scored these units are also available with a Stri-Face. Detail of some standard grooves shown right.

   

 

 
Calculating Equivalent Thickness

If this hollow unit is 50% core voids

It's equivalent solid thickness is 4"

 Equivalent thickness is the solid thickness that would be obtained if the same amount of concrete contained in a hollow unit were re-cast without core holes.

Calculating Estimated Fire Resistance Example: An 8" hollow masonry wall is constructed of expanded slag units reported to be 55% * solid. What is the estimated fire resistance of the wall?  (modular units)

Eq Th = 0.55 x 7.625 in. = 4.19 inches.

From Table: 3 hr. Fire Resistance requires 4.20 inches. Use minus 3 hr. est. resistance.

* Percentage solid can be calculated from net area or net volume values as determined by ASTMC 140 "Methods of Testing Concrete Masonry Units."
Concrete Masonry Estimated Fire-Resistance Rating
Estimated Fire-Resistance Ratings
Concrete Masonry Walls
Wall or Partition
Assembly		 Members Framed Into Wall or Partition
None or Noncombustible
Concrete Masonry Units 4-Hr. 3-Hr. 2-Hr. 1-Hr.
Expanded Slag or Pumice Aggregates 4.7 4.0 3.2 2.1
Expanded Clay or Shale Aggregates 5.7 4.8 3.8 2.6
Limestone, Cinders, or Unexpanded Slag Aggregates 5.9 5.0 4.0 2.7
Expanded Shale, Clay or Slate Aggregates (Rotary Kiln Process) 5.35 4.50 3.95 2.6
Calcareous Gravel Aggregates 6.2 5.3 4.2 2.8
Siliceous Gravel Aggregates 6.7 5.7 4.5 3.0
Note (a):   Where combustible members are framed into the wall, the wall must be of such thickness or be so constructed that the thickness of solid material between the end of each member and opposite face of the wall, or between members set from opposite sides, will not be less than 93% of the thickness shown in table.

Note (b):  The minimum nominal thickness of loadbearing concrete masonry walls (not including thickness of plaster) shall be not less than 6" for single wythe walls and not less than 10" (two 4" wythes plus 2" air space) for cavity walls.  For more information check local codes.