PHMSA Proposes Increased Pressure in Low-Risk Gas Pipelines
The Pipeline and Hazardous Materials Safety Administration proposed a rule today that would increase the maximum allowable operating pressure in some gas transmission pipelines above what its regulations currently allow. The action reflects improved pipeline materials, assessment tools, and maintenance practices that "have significantly reduced the risk of failure in steel pipeline fabricated and installed over the last twenty-five years," the agency said in the rule.
PHMSA said it wants to limit the change to pipelines that pose a low safety risk based on location, materials, and construction. The agency is accepting comments through May 12 (reference Docket ID PHMSA-2005-23447 and submit them via www.regulations.gov.
The current standards for calculating maximum allowable operating pressure of gas transmission pipelines were adopted in 1970 in the original federal pipeline safety regulations. "Almost all risk controls on gas transmission pipelines have been strengthened in the intervening years," according to the rule, "beginning with the introduction of improved manufacturing, metallurgy, testing, and assessment tools and standards. Pipe manufactured and tested to modern standards is far less likely to contain defects that can grow to failure over time than pipe manufactured and installed a generation ago. Likewise, modern maintenance practices, if consistently followed, significantly reduce the risk that corrosion, or other defects affecting pipeline integrity, will develop in installed pipelines. Most recently, operators' development and implementation of integrity management programs have increased understanding about the condition of pipelines and of how to reduce pipeline risks."
Since mid-2006, PHMSA has granted a few special permits on a case-by-case basis to operate pipline segments at higher pressures. In response, PHMSA studied the operating history of lines already operated at higher stress levels in Canada and Britain. Today's proposed rule will put in place a process for managing the life cycle of pipelines operating at a higher stress level. The rule says the life cycle management "goes beyond the operations and maintenance practices, including integrity management, to address steel production, pipeline manufacture, pipeline design, and installation."