Fire Ratings

FIRE RATINGS for CONCRETE MASONRY UNITS

Using Equivalent Thickness Method

Conforms with:
National Concrete Masonry Association (NCMA) Tek 7-1A (2003) International Building Code (2006)

FIRE RATINGS – HOURS
UNIT WIDTH BLOCK TYPE FACE
SHELL
%
SOLID
EQUIVALENT
THICKNESS
NORMAL WEIGHT
CONCRETE
(Siliceous Gravel)
MEDIUM WEIGHT
(105-125lb per cubic ft blended)
LIGHT WEIGHT
(Under 105lbs per cubic ft)
(Expanded clay, shale or slate)
4″
4″
3 Core Regular
Solid
1.0″
Solid
76%
100%
2.7
3.6
3/4
1-1/2
1
1-1/2
1
1-1/2
6″
6″
6″
2 Core Regular
3 Core 75% Solid
Solid
1.06″
2.0″
Solid
56%
75%
100%
3.1
4.2
5.6
1
2
3
1
2
3-3/4
1
2
4
8″
8″
8″
8″
8″
2 Core Regular
2 Core 58% Solid
2 Core 62% Solid
3 Core 75% Solid
Solid
1.25″
1.5″
1.5″
2.25″
Solid
53%
58%
62%
75%
100%
4.0
4.4
4.7
5.7
7.6
1-1/2
2
2
3
4
2
2
2
3
4
2
2
3
4
4
10″ 2 Core Regular 1.25″ 51% 4.9 2 2 3
12″
12″
2 Core Regular
2 Core 56% Solid
1.5″
2.125″
50%
50%
5.8
6.5
3
4
3
4
4
4

Most of these units are normally stocked by A. Jandris & Sons, Inc.

Note:
Increasing Fire Ratings: Walls composed of hollow concrete masonry units having a nominal thickness of 8 inches or greater and having a fire resistance rating of at least 2 hours shall be classified as 4 hours when the hollow spaces are completely filled with perlite or vermiculite, grout or a material such as expanded slag, clay shale, slate or sand.

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