Title:
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Consideration by the Board of County Commissioners to establish and approve means and methods for the disposition of AC pipe by utilizing any of the three methods: (1) Open Trenching; (2) Close Tolerance Pipe Slurrification (CTPS); (3) Cap and Grout in Place as the approved disposition method for AC Pipe that is to be taken out of service. District2 - Zembower and District4 - Lockhart (Tony Nelson, County Engineer)
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Division:
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Public Works - Engineering
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Authorized By:
Jean Jreij, Director of Public Works
Contact/Phone Number:
Tony Nelson/407-665-5763
Background:
The City of Casselberry has an ongoing Northgate Water Main Replacement, Phase 1, project which include the Cap and Grouting of existing in-place AC pipe in county right-of-way. The city has requested approval from staff for approval of the Cap and Grout in place AC method on this project. The Public Works Engineering Manual and Land Development Code state that all out of service AC Pipe shall be removed from the county right- of-way. The Engineering Manual is currently undergoing an update which will include the Cap and Grout in Place method for the treatment of AC pipe. It is the intent of Seminole County is to comply with all federal and state laws, regulations, and guidelines related to the disposition of (AC) pipe that is taken out of services in the right-of-way, including the requirements of the United States Environmental Protection Agency’s Asbestos National Emission Standard for Hazardous Air Pollutants (NESHAP).
The three EPA approved methods are:
Open Trench: Open trenching involves excavating the entire AC pipe, wet-cutting the pipe into sections using a snap cutter or similar tool, wrapping the pipe for containment, and removing the pipe for disposal.
Close Tolerance Pipe Slurrification (CTPS): CTPS involves replacing existing AC pipe completely underground (trenchless), while minimizing the disturbance of above ground structures such as buildings or roadways. With this method, the AC pipe is simultaneously ground up and turned into a cementitious slurry, which is removed by a vacuum truck. A small portion of the slurry (skim coat) remains around the new pipe. The skim coat resolidifies into cement that is nonfriable. When used correctly, CTPS should not leave friable asbestos in the ground.
Cap and Grout in Place: Under this method, the AC pipe is filled with grout to increase strength and stability, capped at both ends, and left in place. The “out of service” AC pipe must be noted permanently in utility records, via GPS Coordinates and in GIS format, and removed at the expense of the entity that capped and grouted the pipe in place if future utility conflicts become apparent in the future. By abandoning the AC pipe in place and installing new line (adjacent or at a different location) without disturbing the existing AC, the pipe replacement project would not be subject to the United States Environmental Protection Agency’s NESHAP requirements. However, if the abandoned AC pipe is acted on in the future in a way that causes the pipe to become friable or otherwise hazardous, the NESHAP would apply and the hazardous condition would have to be remedied at the expense of the entity that capped and grouted the pipe in place.
Requested Action:
Staff recommend the Board approve and authorize the City of Casselberry to utilize the Cap and Grout in place AC pipe treatment method, while the Public Works Engineering Manual is being updated to allow this method.