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ASTRA-GLAZE-SW®+ Fire Ratings Table
Thickness
|
|
Minimum
Thickness
|
Solid
Volume
|
Equivalent
Solid Thickness
|
Fire
Rating
|
Weight Per
Unit Light
|
Nominal
|
Actual
|
Type
|
Shell
Inches
|
Web
Inches
|
Percent
|
Inches
|
Hours
|
Weight
Pounds
|
4"
|
3 5/8"
|
hollow
|
1.00
|
1.00
|
72
|
2.61
|
1
|
21
|
6"
|
5 5/8"
|
modified hollow
|
1.38
|
1.00
|
65
|
3.66
|
2
|
27
|
8"
|
7 5/8"
|
hollow
|
1.25
|
1.00
|
53
|
4.04
|
2
|
33
|
semi-solid
|
2.25
|
1.25
|
80
|
6.10
|
4
|
49
|
10"
|
9 5/8"
|
hollow
|
1.50
|
1.12
|
54
|
5.18
|
3
|
36
|
12"
|
11 5/8"
|
hollow
|
1.50
|
1.25
|
52
|
6.05
|
4
|
44
|
The fire ratings shown are based on data published by the National Concrete
Masonry Association in NCMA TEK 7-1 and the National Bureau of Standards Report
BMS 92. Table 26.
The above fire resistance ratings are based on plain walls; and application
of gypsum plaster (1/2") will add 1/2 hour to ratings. Other aggregates
not included above may have slightly different fire ratings.
The masonry industry and building codes have adopted a standard method for
computing fire resistance ratings of concrete block based on the aggregate used
and the amount of solid content of the blocks used.
Data based on units 7 5/8" high by 15 5/8" long
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