Blended Aggregates

The fire resistance rating of units manufactured with a combination of aggregate types is determined by linear interpolation based on the percent, by volume, of each aggregate used in the manufacture. This may be expressed by the following equation: Tr = (T1 x V1) + (T2 X V2) Where: Tr = required equivalent thickness for a specific fire resistance rating of an assembly constructed of units with combined aggregates. (Value may be inches or mm.) T1, T2 = required equivalent thickness for a specific fire resistance rating of a wall constructed of units with aggregate types 1 and 2, respectively. (Value may be inches or mm.) V1, V2 = fractional volume of aggregate types 1 and 2, respectively, used in the manufacture of the unit. (Value is expressed in % volume of aggregate type.)