The U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA), along with the Pennsylvania Public Utility Commission (PUC), oversees the safe operation of pipelines. These regulations require enhanced protection for defined “High Consequence Areas” (HCA) areas, which include urbanized areas delineated by the U.S. Census Bureau, Unusually Sensitive Areas (USAs), and commercially-navigable waterways.

One of the measures utilized to protect HCAs is to upgrade existing main line valves, or add new valves to act as “emergency flow restriction devices” (EFRDs). Such valves can be controlled remotely by the pipeline control center at all times. Some ERFD valves can also automatically close in response to changes in pressure that could signal a problem with the pipeline system, and trigger a system-wide shut down. EFRD valves are placed strategically along the pipeline as determined via risk analysis evaluations to minimize potential impact to HCA areas in the event of a pipeline emergency.

Pipelines regulated under 49 CFR 195 are assessed for integrity at least once every five years. These assessments are carried out via the use of in-line inspection tools or, a via a hydrostatic pressure test. The in-line inspection tools have the ability to detect conditions on the pipeline which may require repair. Necessary repairs are identified along the length of the pipelines, with priority given to those repairs located within HCAs in accordance with federal regulations. Hydrostatic pressure testing involves filling the pipeline with water and pressurizing that water above the pipeline’s Maximum Operating Pressure. Pressure testing has the ability to identify critical flaws that require repair prior to refilling the pipeline.

Mariner East 2 will be constructed using new pipe and will be hydrostatically tested prior to being placed into operation. Aerial patrols are targeted to be performed at least 26 times a year (twice a month, weather permitting) and any two flights should not be spaced more than three weeks apart. Sunoco Logistics conducts flights more frequently than is required and supplements these activities with ground patrols in several areas. These aerial patrols monitor for any activity on the pipeline right-of-way and for any other potential problems or condition that could threaten the integrity of the pipeline.

In addition to the Aerial patrols conducted, Sunoco pipeline conducts inspections of their pipelines with an inspection tool commonly referred to as “smart pigs”. These tools travel through the pipes internally measuring wall thickness and other features to detect suspected defects and/or corrosion. If there are any problems, Sunoco ensures they will make any necessary repairs so the line is operating safely.