79
3220.038
Equivalent Thickness Fire Rating Tables
Paper
New York State Concrete Masonry Association
1993
January 5
1-117
N
The reference tables are designed to make it easier for one to formulate various blended mix designs using several types of aggregates as found in NCMA Tek 6A, Table 6.0. By using the tables you do not need to work through tghe formula of TR = (T1 X Vl) + (T2 X V2).
Fire ratings of 4″, 6″, 8″, 10″, and 12″ CMU are provided. It must be noted that values published in the tables are based on information found in NCMA Tek Note 6A: Fire Resistance Ratings of Concrete Masonry Assemblies, Table 6.0: Fire-Resistance Rating Period of Concrete Masonry Assemblies.
The resulting solid equivalent thickness values are based on the ACTUAL THICKNESS REQUIRED to meet a given fire rating based on a given aggregate blending.
Additional values are based on the MINIMUM SOLID PERCENTAGE allowed by ASTM C90-92, of which CMU must conform.
The blends evaluated are as follows:
1. CMU manufactured with blend of Type “A” aggregate (calcareous/siliceous gravel) and Type “B” aggregate (limestone/cinders/slag) for fire resistance rating periods of 30, 45, 60, 90 minutes, 2 3 and 4 hours.
2. CMU manufactured with blend of Type “A” aggregate (calcareous/siliceous gravel) and Type “C” aggregate (expanded clay/shale/slate) for fire resistance rating periods of 30, 45, 60, 90 minutes, 2, 3 and 4 hours.
3. CMU manufactured with blend of Type “A” aggregate (calcareous/siliceous gravel) and Type “D” aggregate (expanded slag/pumice) for fire resistance rating periods of 30, 45, 60, 90 minutes, 2, 3 and 4 hours.
4. CMU manufactured with blend of Type “B” aggregate (limestone/cinders/slag) and Type “C” aggregate (expanded clay/shale,slate) for fire resistance rating periods of 30, 45, 60, 90 minutes, 2, 3 and 4 hours.
5. CMU manufactured with blend of Type “B” aggregate (limestone/cinders/slag) and Type “D” aggregate (expanded slag/pumice) for fire resistance rating periods of 30, 45, 60, 90 minutes, 2, 3 and 4 hours.
6. CMU manufactured with blend of Type “C” aggregate (expanded clay,shale/slate) and Type “D” aggregate (expanded slag/pumice) for fire resistance rating periods of 30, 45, 60, 90 minutes, 2, 3 and 4 hours.