Are You Compliant? PHMSA Advisory Bulletin: Centerline Surveys Essential
On December 13, 2016, the Pipeline and Hazardous Materials Safety Administration issued an advisory bulletin to remind gas transmission line operators of best methods for identifying, mapping, and properly accounting for High Consequence Areas (HCAs). While the bulletin generally revisits standards previously conveyed, it speaks clearly to the expectations for operators’ diligence in remaining vigilant and compliant with federal law.
Pipeline operators are obligated under 49 CFR 192 subpart O to identify the segments of their lines that pose the greatest risk to the public – otherwise known as HCAs. Because of the heightened risk to life, property, and the environment, operators must survey the entire pipeline system to identify and maintain the segments within HCAs. Understandably, these HCAs require comprehensive Integrity management programs. But despite these clear requirements, a “review of PHMSA and state data from ‘first-round’ [Integrity Management] inspections indicate[d] a large percentage of intrastate and small operators have been inconsistent in determining HCAs using ‘identified sites.’”
Centerline Surveys Decrease PIR Calculation Error
The Potential Impact Radius (PIR) calculation stands as a key component of pipeline operators’ risk mitigation strategies. A PIR measures the radius surrounding a potential point of failure, otherwise known as a Potential Impact Circle (PIC). And while PHMSA allows for a “buffer zone” to help operators account for inaccuracies in that calculation, the better and safer approach is to minimize or eliminate inaccuracies altogether.
According to the National Transportation Safety Board publication SS-15-01, Safety Study: Integrity Management of Gas Transmission Pipelines in High Consequence Areas, “PHMSA has noted that proper identification of an HCA and periodic verification relies on two key types of information: (1) Pipeline-specific information that includes the accurate location of the centerline of the pipeline, the nominal diameter of the pipeline, and the pipeline segment’s MAOP; and (2) all the structures and their usage (including occupancy) located along the pipeline.”
Ultimately then, critical to conducting an accurate PIR calculation is the availability of correct centerline data.
Maintaining Updated Maps and Centerline Data
PHMSA consistently communicates its expectation that “most large operators will use a geographic information system or similar mapping software for segment identification.” For those operators to maintain and produce the appropriate graphical overlay of HCAs on their system, PHMSA encourages them to “continually improve the accuracy of their pipeline data.”
The Agency specifically points to improving technology as key to compliance:
“As technology advances, pipeline operators have more access to tools that provide improved accuracy for determining class locations (including the determination of the centerline of the pipeline).”
In its concluding guidance, the Bulletin exhorts operators to “continuously improve the accuracy of the data . . . and update their maps each calendar year.” Integral to that effort will be “review[ing] their pipeline centerline and map data to account for any potential inaccuracies or data limitations and to add an appropriate buffer zone to the calculated PIR.”
PipeTrak Centerline Data Solutions
Southern Brush provides PipeTrak services to help operators remain compliant with state and federal law. Using state-of-the-art equipment and innovative software solutions, we can capture a pipe’s centerline with sub-centimeter accuracy. And we package data deliverables to match our customers’ various GIS system requirements. Maintaining correct PIR calculations and effectively managing enterprise risk requires accurate centerline maps. PHMSA expects that of operators and Southern Brush helps them achieve it.
If we can provide you with line locating, centerline or depth-of-cover surveys, or any of our traditional right-of-way maintenance services like mowing and vegetation control, please contact us today.