electrician was removing an inoperable RTD (resistance temperature detector)
from a Thermo-well from an active main Glycol line (12”, 25% solution, -5 C).
After visually inspecting the assembly behind the foam insulation, he believed
the connection (between thermo-well and pipe) was welded, but it was threaded.
As he unscrewed the RTD from the Thermo-well, the Thermo-well came out along
with the RTD. This released glycol from a charged line causing it to leak,
spray and spill approximately 6,000 - 7,000 gallons. Most of the glycol was
recovered from the secondary containment, but approximately 1,800 gallons had
to be replaced. The worker tried to put the assembly back into the pipe which
did not work and subsequently caused glycol to spray his chest/body/face. The
line was under approximately 60 psi of pressure. The worker was decontaminated
in the men’s locker room in the next building and then sent to medical for
evaluation. The worker was released with no injury and he returned to work the
next day. Utilities shutdown the system for a few hours and first responders
put the assembly back into the pipe while donning a level A. The system was
back-up and running around noon the same day. New glycol had to be purchased
and an environmental remediation company responded to remediate the floor,
associated components, and some white rock outside the exterior door. An RCA
was requested by management to understand what happened and how to improve for
Factors to consider
at your site or on your project include, but are not limited to, the following:
Consider potential releases from
Consider atypical pipe connections
prior to disassembly.
Consider having a pipefitter remove
pipe assemblies such as RTDs instead of electricians.
Remove all obstructions, such as
insulation, to view pipe connections.