106 Chapter 3
Table 3.4 : Continued
Materials Coeffi cient
125 Hz 250 Hz 500 Hz 1 kHz 2 kHz 4 kHz
Rockwool blanket, 2-in.-thick batt
(Semi-Thik), covered with 3/16 in.- thick
perforated cement-asbestos board
(Transite), 11% open area
Mounted against solid backing
Mounted over 1-in. air space
Mounted over 2-in. air space0.23
0.39
0.390.53
0.77
0.670.99
0.99
0.990.91
0.83
0.920.62
0.58
0.580.84
0.50
0.48
Rockwall blanket, 4-in.-thick batt
(Full-Thik)
Mounted against solid backing
Mounted over 1-in. air space
Mounted over 2-in. air space0.28
0.41
0.520.59
0.81
0.890.88
0.99
0.990.88
0.99
0.980.88
0.92
0.940.72
0.83
0.86
Rockwool blanket, 4-in.-thick batt
(Full-Thik), covered with 3⁄16-in.- thick
perforated cement–asbestos board
(Transite), 11% open area
Mounted against solid backing
Mounted over 1-in. air space
Mounted over 2-in. air space0.50
0.44
0.620.88
0.88
0.890.99
0.99
0.990.75
0.88
0.920.56
0.70
0.700.45
0.30
0.58
Roofi ng felt, bituminous, two layers,
0.8 lb/ft^2 , mounted over 10-in. air space0.50 0.30 0.20 0.10 0.10 0.10Spincoustic blanket
1 in., mounted against solid backing
2 in., mounted against solid backing0.13
0.450.38
0.770.79
0.990.92
0.990.83
0.910.76
0.78
Spincoustic blanket, 2 in., covered with
3⁄16-in. perforated cement–asbestos board
(Transite), 11% open area0.25 0.80 0.99 0.93 0.72 0.58Sprayed “ Limpet ” asbestos
3/4 in., 1 coat, unpainted on solid
backing
1 in., 1 coat, unpainted on solid backing
3/4 in., 1 coat, unpainted on metal lath0.080.30
0.410.190.42
0.880.700.74
0.900.890.96
0.880.950.95
0.910.850.96
0.81
(Continued)