In September of 2014, PHMSA (the federal Pipeline Hazardous Materials Safety Administration, a division of the Department of Transportation) issued guidelines about the potential hazards from pipeline flow reversals and product changes. The decision to publish the guidelines document was triggered by failures of pipelines whose flow had recently been reversed and whose contents had been changed—in other words, pipelines just like the 12” one that Sunoco is proposing to reverse and repurpose.
Sunoco’s plan is to bypass the incomplete portion of the Dragonpipe (Mariner East 2 pipeline) by using a 12” pipeline from the 1930s that has previously carried refinery products such as diesel fuel to central Pennsylvania. The flow of the pipeline would be reversed and, instead of diesel fuel, it would carry high-pressure, highly-explosive “natural gas liquids” through much of Chester and Delaware County. This is a seriously flawed idea, and the PHMSA guidelines warn against it.
Here are the opening sentences of the guidelines document:
PHMSA is issuing this advisory bulletin to alert operators of hazardous liquid and gas transmission pipelines of the potential significant impact flow reversals, product changes and conversion to service may have on the integrity of a pipeline. Failures on natural gas transmission and hazardous liquid pipelines have occurred after these operational changes.
Later in the document, PHMSA warns against some specific cases in which this type of repurposing would be ill-advised (italics added to the parts that are known to apply to the 12” pipeline):
…it may not be advisable to perform flow reversals, product changes or conversion to service under the following conditions:
- Grandfathered pipelines that operate without a Part 192, Subpart J pressure test or where sufficient historical test or material strength records are not available.
- LF-ERW pipe, lap welded, unknown seam types and with seam factors less than 1.0 as defined in § § 192.113 and 195.106.
- Pipelines that have had a history of failures and leaks most especially those due to stress corrosion cracking, internal/ external corrosion, selective seam corrosion or manufacturing defects.
- Pipelines that operate above Part 192 design factors (above 72% SMYS).
- Product change from unrefined products to highly volatile liquids.
PHMSA is explicitly calling out as “inadvisable” exactly the type of repurposing that Sunoco proposes. It is hard to imagine a more specific warning from a government agency.
Sunoco may be able to claim that its previous project, to reverse and repurpose what is now called “Mariner East 1”, was underway before these guidelines were issued. It cannot make that claim for the 12” pipe now. This is a very dangerous undertaking and should be stopped immediately.