Underground Infrastructure - July 2023 - 21

REHABTECHNOLOGY
Details from the Latest NASSCO Phase 3 Study
Breakthrough Time of Styrene Emissions
Through Various CIPP Coating Materials
Dr. John Matthews, Director, and Quade Wells, Lab Manager | Trenchless Technology Center
Recent studies of cured-in-place pipe (CIPP) liners have
shown that potentially dangerous concentrations of styrene can
be emitted prior to liner installation in the cold storage unit or
vehicle. Although, the studies showed that the risks of styrene
exposure can be easily mitigated, there is still a need to further
enhance our understanding of CIPP emission characteristics to
help create a cleaner and safer work environment and ensure
public safety.
This article will highlight the steps taken through a recent
study to better understand the characteristics of styrene emissions
in the transport and storage of the liner in the refrigerated
chamber. The study featured a secure testing chamber that utilized
photoionization (PID) sensors to determine the levels of
styrene released over a set amount of time for uncured liners
with various types of coatings (PE, PU, PP, etc.).
The PID sensors sampled the rate of styrene in the enclosed
area measured in parts per million. Information gathered in this
study allowed for easier determination of safe styrene emission
levels after being held in the refrigerated transport truck for
various periods of time. Finally, field validation was performed
using an actual transport truck containing various CIPP liners.
The goal of this study was to further increase knowledge and
understanding of CIPP emissions characteristic. Furthermore,
it was hoped to create a cleaner and safer environment for employees
and the public.
These goals were accomplished through the following objectives:
*
Study 1 - Lab Scale Study: The lab scale portion of the test
featured a secure enclosed testing chamber that represents
the refrigerated truck that liners are transported on to job
sites. Several PID sensors were utilized in the testing to help
determine the levels of styrene over various periods of time.
Information gathered from this lab scale study test can be
directly correlated to safe levels of styrene emission over a
set period.
* Study 2 - Field Study: The field study was conducted
to validate the results found from the lab scale study. The
IMAGE 1. Secure testing chamber that represents the refrigerated
transport truck.
same PIDs used for the lab scale study were applied in the
field to an installation operation. Here, we could see how
the styrene emissions reacted in a real refrigerator transport
truck and job site to make a more accurate determination of
crew and public safety.
Lab scale study
The first step taken in completion of the lab scale study was to
create a testing chamber. The Trenchless Technology Center
(TTC) modified a chest freezer to be the secure temperature-controlled
testing chamber. It was fitted with four outlets
where the styrene emissions could be recorded.
TTC wet-out all the liners in-house using various material
coating liners, resin, rollers and vacuum pumps. Both ends of
the liners were closed off using a nylon wrap and duct tape to
ensure no styrene escaped from either end.
On completion of the wet-out process, the resin-impregnated,
uncured liner was placed in the secure chamber. The goal was to
compare the baseline VOC taken in the chamber prior to loading
and compare it to the buildup of styrene levels over a set period.
UndergroundInfrastructure.com | JULY 2023 21
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Underground Infrastructure - July 2023

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