Since 1924

 
 

FIRE RESISTANCE TABLES

These charts are designed to help you quickly and conveniently reference technical information. If the charts do not answer your specific questions, please make use of the National Concrete Masonry Association (NCMA) giving you access to all of NCMAs Tech bulletins. Contact us if you cannot find the technical information you need.

Fire resistance of concrete masonry walls is a function of aggregate type and equivalent thickness of the masonry units.

The following ratings are figured using the actual percent of solids in the various sizes of blocks as manufactured by Capitol Concrete Products Co. Inc., Topeka, Kansas.

The ratings are based on test information obtained from Underwriters' Labratories Inc., National Bureau of Standards, Portland Cement Association, and Uniform Building Code.

      FIRE RESISTANCE
IN HOURS
AS MANUFACTURED BY CAPITOL CONCRETE PER- CENT SOLID EQUIVALENT THICKNESS LIGHT- WEIGHT EXP. SHALE NORMAL- WEIGHT LIMESTONE
BRICK 100.0 3.63 2.0 1.0
4" STANDARD CORES 73.4 2.66 1.0 1.0
4" SOLID 100.0 3.63 2.0 1.0
6" STANDARD CORES 54.5 3.07 1.0 1.0
6" SPECIAL 2-HOUR CORES 70.0 3.93 2.0 1.0
6" SOLID 100.0 5.63 4.0 3.0
8" STANDARD CORES 53.0 4.04 2.0 2.0
8" SPECIAL 4-HOUR CORES 75.0 5.72 4.0 3.0
8" SOLID 100.0 7.63 7.0 6.0
12" STANDARD CORES 48.7 6.66 4.0 3.0
12" SPECIAL 3 CORE 55.9 6.80 4.0 4.0

For additional information see:
Concrete Masonry Manual published by Expanded Shale, Clay and Slate Institute. section 9 - "Fire Resistance" pages 27, 28 and 29

Concrete Masonry handbook published by Portland Cement Association "Fire Resistance of Concrete Masonry" pages 12 and 13

Tek 35c "Fire Safety with Concrete Masonry" published by National Concrete Masonry Association

Uniform Building Code - section 4302(a) - table 43-b, 1985 edition and 1986 supplement

 

 

 



 
 
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