Underground Infrastructure - July 2023 - 24

Rehab Technology
Depicted in TABLE 5, is a summarization of the key measurements
taken from both Tampa and Milwaukee. Th e liners
installed in Florida were a 17-millimeter PP coated liner, while
the Wisconsin liners were 15-millimeter PU-coated.
In the fi eld, with similar coatings and thickness, the breakthrough
curve was steeper than what was found in the lab scale
study, although the maximum concentrations measured in the
fi eld were similar or less than what was discovered in the lab.
Both fi eld studies followed the same trend. As the doors were
opened to perform the installation, the concentration would decrease.
Once the doors were shut, there would be an increase until
the concentration reached a peak and would then begin to decrease
over time. Upon reviewing the data displayed in TABLE 5,
as each liner was removed from the truck the concentration would
decrease and continue to decrease over subsequent weeks.
Conclusion
Th e time to breakthrough is at least partially based on the materials
used and the thickness of those materials. For the same
material of diff erent thicknesses (i.e., PU at 15 millimeters vs 24
millimeters) the thinner liner allowed breakthrough to happen
sooner. Once the door of the cold storage or transport vehicle
was opened, emissions levels dropped very quickly to below
OSHA and NIOSH recommended levels.
For the two diff erent contractors who were followed, the
data showed that over the course of a week of installations,
the styrene levels slowly reduced each day aſt er liners were removed.
Although that may seem intuitive, there is still residual
styrene in the storage trucks to be aware of, even aſt er all liners
have been removed.
In the fi eld, for similar coatings and thickness, breakthrough
concentrations increased more quickly than what was observed
in the freezer test, even for similar percent resin to total storage
volume values. Th is could have been due to the diff erence in
conditions between the fi eld and lab.
Although maximum concentrations in the fi eld were similar
or less than what was observed in the lab, replicating breakthrough
curves in the lab that were similar to the fi eld was not
achieved. Some spot-check readings at both fi eld sites were
higher than the concentrations measured inside the truck and
those measured in the lab. Th is was likely due to the fact that
styrene is heavier than air and the spot-check readings were
taken at the fl oor level of the truck tailgate each time. UI
ACKNOWLEDGEMENTS
The author acknowledges the research team for this project: Drs. Shaurav
Alam, Elizabeth Matthews, and John Kraft, and Quade Wells. TTC also
thanks NASSCO for funding this study. The full study report is located on
the NASSCO website.
FOR MORE INFORMATION
Trenchless Technology Center, Trenchless Technology Center |
Louisiana Tech University (latech.edu)
NASSCO, nassco.org
TABLE 5. Summary of key measurements from Tampa and Milwaukee
Min Conc.
Max Conc.
Installation
Number
Date
IMAGE 6. Graphical illustration of the concentration data from
installation 2 and 3.
TABLE 4. Coating and liner characteristics at the Milwaukee area
installation
Installation
Number
1
2
3
4
5
6
7
8
9
10
Coating
Material
PU
PU
PU
PU
PU
PU
PU
PU
PU
PU
Coating
Thickness
(mil)
15
15
15
15
15
15
15
15
15
15
Liner
Thickness
(mm)
4.5
4.5
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
24 JULY 2023 | UndergroundInfrastructure.com
Liner Diameter
(in) / Wet Tube
Length (ft)
7.8/390
7.8/240
7.8/676
7.8/378
7.8/310
7.8/192
7.8/218
9.875/174
7.8/341
7.8/199
Estimsted
Resin
Weight (lbs)
826
504
1811
801
655
401
457
457
721
416
Truck Loaded 8/26/22
8/29/22
8/29/22
8/30/22
8/31/22
8/31/22
9/1/22
9/1/22
9/1/22
9/2/22
9/2/22
1
2
3
4
5
6
7
8
9
10
Truck Loaded 7/15/22
7/19/22
7/20/22
7/20/22
7/20/22
7/22/22
7/22/22
1
2
3
4
5
6
after Opening
(PPM)
-
35
30
15
30
37
45
-
after Closing
(PPM)
Tampa, Florida
245
260
250
250
215
135
127
Milwaukee, Wisconsin
247
190
200
130
35
60
75
50
10
10
15
50
50
40
50
140
75
120
105
170
N/A
4089
4089
3127
2456
2167
967
136
7049
7049
6223
5719
3908
3107
2452
2051
1594
1137
416
-
3.3
2.5
2.0
1.8
0.8
0.1
-
5.9
5.2
4.8
3.3
2.6
2.1
1.7
1.3
1.0
0.3
Total # of
Resin on
Truck
% of resin
by Total
Volume
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Underground Infrastructure - July 2023

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