Advisory bulletin issued to natural gas cast iron distribution pipelines
On March 23, 2012, the U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) issued an advisory bulletin to reiterate two alert notices previously issued by PHMSA, ALN-91-02 (Oct. 11, 1991) and ALN-92-02 (June 26, 1992) which addressed the continued use of cast iron pipe in natural gas distribution pipeline systems and to remind owners and operators and state pipeline safety representatives of the need to maintain an effective cast iron management program. Recent explosions in Philadelphia and Allenstown, Pennsylvania, which killed 6 people, injured many others and caused significant property damage, involved cast iron pipelines installed in 1942 and 1928, respectively. These incidents emphasized the need for safety improvements to aging gas pipeline systems in the United States.
ALN-91-02 was issued to provide notice to owners and operators of the National Transportation Safety Board’s recommendation, P-91-12. The recommendation advised gas operators to (1) implement a program based on factors such as age, pipe diameter, operating pressure, soil corrosiveness, existing graphitic damage, leak history, burial depth and external loading, (2) identify cast iron piping systems that may threaten public safety, and (3) replace these systems in a planned, timely manner. ALN-92-02 was issued to remind operators that the surveillance, pipeline facility assessment and mitigation requirements stated in 49 CFR 192.613 apply to cast iron pipelines.
In the March 23 advisory bulletin, PHMSA reminds owners and operators and state pipeline safety representatives that these two alert notices continue to be relevant and urges owners and operators to conduct a comprehensive review of their cast iron distribution pipelines and replacement programs and to accelerate repair and replacement of high-risk pipelines. Specifically, PHMSA requests owners and operators to
- Review current cast iron replacement programs and consider establishing mandated replacement programs,
- Establish accelerated leakage survey frequencies or leak testing,
- Focus pipeline safety efforts on identifying highest-risk pipe,
- Use rate adjustments to incentivize pipeline rehabilitation, repair and replacement programs,
- Strengthen pipeline safety inspections, accident investigations and enforcement actions, and
- Install interior/home methane gas alarms.
Owners and operators are further reminded of their responsibilities under 49 CFR 192.617 to establish procedures for analyzing incidents and failures to determine the causes of the failure and to minimize the possibility of a recurrence.
Finally, the advisory bulletin notes that the Department of Transportation, in accordance with the Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011, will continue to monitor the progress made by operators to implement plans of safe management and replacement of cast iron gas pipelines and identify the total miles of cast iron pipelines in the United States.