I
MPACT
E
CHO
(IE)
www.olsoninstruments.com
www.olsonengineering.com
Table 1 – Styrofoam Defect Sizes
Defect ID
Circumferential
Lost (mm, in)
Depth Lost
(mm, in)
Percentage Lost in
Circumferential
Permineter (%)
Percentage
Lost in Depth
(%)
1
50.8, 2
6.35, 0.25
16
6
2
77.2, 3
13.6, 0.535
24
13
3
101.6, 4
23.4, 0.92
32
23
4
127, 5
34.8, 1.37
40
34
5
159.5, 6.28
50.8, 2
50
50
6
192.3, 7.57
66.8, 2.63
60
66
7
217.7, 8.57
78.2, 3.08
68
77
8
243.1, 9.57
87.9, 3.46
76
87
9
268.5, 10.57
95.2, 3.75
84
94
Figure 3 – Styrofoam supported by wire rod (left), the foam rod being inserted into the duct to form voids
(center) and view of Styrofoam defect inside a duct (right)
Figure 4a – Design Grout Defects (Styrofoam Voids) in the South Wall in 101.6 mm (4 inch) Metal Ducts
from top down
