PHMSA Issues Guidance for Operators of Natural Gas Pipelines Regarding High Consequence Area Identification Methods
The U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) has issued an Advisory Bulletin (ADB-2016-07) to owners and operators of natural gas pipelines. The bulletin provides guidance on identifying and periodically verifying High Consequence Areas (HCAs).
PHMSA’s integrity management program for gas transmission pipelines requires an operator to survey its pipeline to identify HCAs. These HCAs consist of highly populated areas where people regularly gather or live and pose the greatest risk to human life, property, and the environment. HCA identification relies on pipeline-specific information regarding location, size, and operating characteristics of the line, as well as the identification of structures, specified sites, and their intended usage along the pipeline right-of-way.
In 2015, the National Transportation Safety Board published a study in response to concerns about deficiencies in integrity management programs related to three pipeline accidents. As part of the study, the NTSB issued a recommendation that the PHMSA assess the limitations associated with the current process for identifying HCAs. Early PHMSA inspections have shown that 28% of operators do not have procedures to identify HCAs using one of the two methods established by the PHMSA’s integrity management program. Thus, the PHMSA issued the bulletin to remind operators of existing guidance and to provide additional recommendations for improving HCA identification.
In the bulletin, the PHMSA reminds operators that it expects large operators to use a geographic information system and be able to demonstrate the usability of the system. An operator without a geographic information system should be able to describe or demonstrate how it performs HCA identification. It also reminds all operators of the need to address how they deal with tolerances (buffers) in addition to the calculated potential impact radius (PIR).
Operators should continuously improve the accuracy of their data, including class location data, for potential inaccuracies or limitations. The PHMSA recommends that operators review class location and PIR data annually as part of their own integrity management program, and use new tools as available through enhancements in technology. It also recommends that operators add a buffer zone to the calculated PIR to ensure proper HCA identification.
The PHMSA Advisory Bulletin is available here.