9 CFR Parts 192 and 195, Docket No. PHMSA-2005-22642
New rules proposed by the PHMSA would help prevent internal pipeline corrosion, one of the leading causes of incidents in gas transmission pipelines for the past five years.
PHMSA – 2005-22642 would add a new section to subpart I—Requirements for Corrosion Control in 49 CFR part 192. The new section, § 192.476, would require an operator to address internal corrosion risk when designing and constructing gas transmission pipelines.
Proposed paragraph (a) provides a performance test for internal corrosion prevention measures in design and construction. The test is whether the design and construction choices include measures to reduce the risk that liquid will collect inside the pipe. The proposed rule would require an operator to use measures that include, at the least, arrangement to avoid collection of liquids and the use of effective liquid removal equipment.
If an operator is unable to avoid low spots, an operator would explain why and identify the alternative measures to reduce the risk. There may be cases in which the design avoids low spots, but during construction the operator finds that it cannot avoid low spots. In this case, the operator would document the ‘‘as built’’ condition and the alternative measures used.
Proposed paragraph (b) provides a performance test for design and construction measures to check any internal corrosion that occurs. The test is whether the design and construction choices include measures to reduce the risk of internal corrosion. The design must allow for use of corrosion detection equipment.
These design and construction requirements would apply to all new construction and to replaced pipe and components.
With one limited exception, application to replaced pipe would be the same as the rule on designing to allow the passage of instrumented internal inspection tools (pigs). PHMSA clarified the meaning of replaced pipe in the final rule published in the Federal Register on June 28, 2004 (69 FR 36024). The exception occurs when replaced pipe changes the physical features of an existing downstream pipeline. Proposed paragraph (c) clarifies that an operator must consider the impact of line changes on internal corrosion risks and plan for these.
Proposed paragraph (c) would not require an operator to rebuild the downstream pipeline to remove low points, but would require an operator to consider whether it should install liquid removal equipment or tools to monitor corrosion. After analysis, an operator may decide O&M; measures would adequately address the impacts of the changes upstream.
Paragraph (d) would require an operator to record the decisions it makes about internal corrosion control when designing and constructing pipelines. The operator would have to explain its reasons for the decisions and justify variance. For example, if an operator did not use equipment to remove liquids in designing a pipeline, the operator would have to explain why the use of the equipment would be impracticable. Recording reasons for decisions fosters better decisionmaking and will provide needed information about safety features of the line in the future.
Anyone interested in filing written comments on the rule proposed in this document must do so by Feb. 13, 2006. Identify the docket number, PHMSA–2005–22642, at the beginning of your comments. You can make comments on the DOT website at http://dms.dot.gov or send hardcopy comments to Docket Management System: U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL–401, Washington, DC 20590– 0001.
For more information, contact Barbara Betsock by phone at (202) 366– 4361 or by fax at (202) 366–4566, or by e-mail at barbara.betsock@dot.gov.