Identifying Canadian high-consequence areas
In 2006, Enbridge identified high-consequence areas for Liquids Pipelines’ Canadian mainline system. These areas include high- and medium-populated areas, drinking-water intakes, environmentally sensitive areas, and commercially navigable waterways. As a result, we now include these areas to generate our 2007 risk assessment results and identify potential remote-controlled-valve locations. In both cases, knowledge of these high-consequence areas is used to identify additional risk prevention and mitigation measures that can be put in place to provide extra protection.
Upgrading containment features
Since 2002 in Canada and 2004 in the United States, Enbridge has been upgrading our containment features at facilities to minimize the potential for off-property non-tankage releases. This work continued into 2006 and is expected to carry forward until at least 2008.
Carrying out pipeline integrity “digs”
Our ongoing program of maintenance “digs” involves excavating sections of pipeline to inspect and repair pipe to maintain high levels of system integrity. In 2006, we completed 72 in-line inspections and completed over 600 digs along our mainline Liquids Pipelines system in Canada and the United States.
Our goal is to conduct all maintenance digs to the highest environmental standards. Before beginning work, we complete screening tests to identify environmental issues and measures needed to minimize our impacts to land, vegetation and wildlife. We conduct similar environmental reviews for other small engineering and operation and maintenance projects. We also train inspectors and contractors on safety and environmental requirements and best management practices, and provide environmental specifications for these projects.
Integrity management at Enbridge Gas Distribution
In accordance with pipeline integrity regulations in Ontario, Enbridge Gas Distribution continues to perform in-line inspection of its pipelines that are operating at high stress. In-line inspection is a key part of our Integrity Management Program (IMP), which provides a proactive means to ensure a safe and reliable distribution system.
In 2006, our integrity management department:
- Reviewed and revised the 10-year Baseline Inspection Plan, which prioritizes inspection of pipelines by risk.
- Completed the in-line inspection and data verification for the 39.1-kilometre NPS 36 Parkway North pipeline.
- Completed validation of the in-line inspection of the 55.6-kilometre NPS 8 Collingwood line, including the measurement of 45 metal loss and 20 dent indications. Mitigation of six remaining dents in the line is planned for 2007.
- Completed as far as possible retrofitting of the lines scheduled for in-line inspection in 2007.
In addition to pipelines, our IMP program includes managing the condition of the inlet piping to gate stations. In 2006, we replaced the inlet piping to our Lisgar Gate Station with a higher grade of pipe. This lowered the stress developed at maximum operating pressure so we were able to remove this inlet from the program. We used the inlet piping to Haley Gate Station for field trials of new guided wave ultrasonic inspection equipment and in the process detected no indications requiring repair. We were also able to remove two other gate stations from the program by conducting detailed records searches on the grade and wall thickness of the inlet piping to determine that stress levels were acceptable.
Since 2003, pipeline integrity regulations in Ontario have required operating companies to complete a ‘depth of cover’ survey of all high-stress pipelines that are located in agricultural areas. The frequency of the survey is left to the operating company and we have chosen to complete it every three years. We completed our second survey in 2006. We identified one area of non-compliance and made plans to return that location to compliance in the summer of 2007.
Enbridge Gas Distribution provided Structural Integrity Associates and The Welding Institute with four locations for their field trials of guided wave ultrasonic inspection equipment. We also participated in validation testing of both organizations’ systems in a Northeast Gas Association study of the emerging technology.
Integrity management in the United States
Our United States Gas Transportation Business introduced an IMP in 2005 to comply with a federal regulation requiring gas transmission pipeline operators to develop such programs for pipelines located where a leak or rupture could do the most harm. Under the regulation, operators are required to: perform ongoing assessments of pipeline integrity; improve data collection, integration, and analysis; repair and remediate pipelines as necessary; and implement preventive and mitigation actions.
Our comprehensive IMP initiatives in 2006 included:
- assessing pipeline segments that are located in high-consequence areas on a prioritized basis;
- developing aerial maps to aid in the assessment;
- adding enhanced processes and procedures to ensure compliance with new regulations regarding audit protocols that were introduced during the year; and
- expanding our systems integrity department to manage the added work stemming from the regulation.
In the first quarter of 2006, the United States Pipeline Hazardous Materials and Safety Administration conducted an audit of the business unit’s IMP. The audit was a joint effort between federal and state inspectors to help ensure compliance with federal safety regulations.
Enbridge Pipeline Data Management System
In 2006, the United States Gas Transportation Business continued work on developing an integrated geographic information system for pipeline data management. The system will contribute to compliance with new federal pipeline safety regulations requiring operators to improve data integration and analysis.
Integrity Compliance Activity Manager
In 2006, the United States Gas Transportation Business worked on development and implementation of a tool to link its IMP "framework" to the creation of its actual processes. This will aid in the management of internal processes, as well as provide a platform to address compliance with all inspection protocol requirements.
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