OPS Proposes Standards for Direct Assessment of Gas and Hazardous Liquid Pipelines

On October 21, the Department of Transportation’s Office of Pipeline Safety issued a Notice of Proposed Rulemaking that would require pipeline operators to meet certain standards if they use direct assessment to evaluate the threat of corrosion on onshore natural gas, hazardous liquid, and carbon dioxide pipelines. This proposal would extend the standards already applicable to gas transmission lines located in high consequence areas (HCA) to onshore natural gas pipelines not located in HCAs and to hazardous liquid and carbon dioxide pipelines.

The Pipeline Safety Improvement Act of 2002 required the DOT to issue regulations prescribing standards for inspecting pipeline facilities by direct assessment, which has been done for gas pipeline operators located in HCAs. To fulfill the second part of Congress’s directive, the instant rulemaking expands the use of those standards to onshore gas pipelines not located in HCAs and to hazardous liquid and carbon dioxide pipelines. Direct assessment is one of three methods used for testing pipeline integrity – the other two being internal inspection and pressure testing.

Proposed Standards for Direct Assessment

The proposed regulations would require that operators of onshore pipelines that elect to use direct assessment do so in compliance with the standards recently adopted (68 Fed. Reg. 69778, December 15, 2003) for application to gas transmission lines in HCAs. Direct assessment is a process that provides a systematic framework for an operator’s review of certain threats. The regulations include standards for using direct assessment to evaluate the threats of external corrosion, internal corrosion, and stress corrosion cracking.

The standard regarding external corrosion direct assessment requires operators to: (1) integrate data on physical characteristics and operating history; (2) conduct indirect aboveground inspections; (3) directly examine pipe surfaces; and (4) evaluate the effectiveness of the assessment process.

Under the proposed standard for direct assessment of internal corrosion, operators would be required to: (1) predict locations where electrolytes might accumulate in normally dry-gas pipelines; (2) examine those locations; and (3) validate the assessment process.

The proposed standard for direct assessment of stress corrosion cracking would require operators to: (1) collect data relevant to stress-corrosion cracking; (2) assess the risk of pipeline segments; and (3) examine and evaluate segments at risk. The one exception to this wider application of direct assessment standards is that the Research and Special Programs Administration (RSPA) does not believe that the direct assessment provisions addressing internal corrosion in pipelines that transport dry gas is suitable for hazardous liquid pipelines. The RSPA notes that, at present, there is no consensus standard available for the direct assessment of internal corrosion in hazardous liquid pipelines.

Public Comment

The RSPA invites comments on the questions of: (1) how many operators plan to use direct assessment, other than to meet the transmission integrity management rules; and (2) the average paperwork burden of complying with the proposed rulemaking in hours and cost per hour.