USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #PI-21-0004

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Pacific Gas and Electric Company

Individual Name: Ms. Christine Cowsert

Location State: CA Country: US

View the Interpretation Document

Response text:

Ms. Christine Cowsert
VP, Gas Asset Mgmt. & System Operations
Pacific Gas and Electric Company
6121 Bollinger Canyon Road
San Ramon, CA 64583

Dear Ms. Cowsert:

In a letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA), dated April 28, 2021, you requested an interpretation of 49 Code of Federal Regulations (CFR) Part 192. Specifically, you requested an interpretation of 49 CFR § 192.939.

You asked when must an assessment of a newly activated threat be completed in an existing high consequence area (HCA) if the threat is newly activated during the reassessment period provided by 49 CFR § 192.939. You stated your concern is that when a newly activated threat becomes active shortly before the conclusion of a scheduled reassessment cycle, an integrity assessment for the covered segment would not be complete if not all threats present at the start of the next scheduled reassessment cycle have been assessed. In addition, you mentioned your discussion with the California Public Utilities Commission (CPUC) and their interpretation of the applicability of the regulations, and provided examples and excerpts of the regulations as appendices.

PHMSA agrees with the CPUC's assessment that 49 CFR § 192.939 does not have an exception for newly discovered threats within existing HCAs if they are discovered within an assessment cycle. Therefore, a pipeline operator must assess a newly activated threat on a covered segment within the same assessment cycle as other threats that were previously identified through risk assessment under 49 CFR § 192.917(a) regardless of when the threat becomes active. PHMSA recognizes that an operator may not be able to comply with the requirements stated in 49 CFR § 192.939 in limited instances, in which case PHMSA may allow a waiver from a reassessment interval required by 49 CFR § 192.939 if the waiver would not be inconsistent with pipeline safety. Those limited instances include where an operator cannot obtain the internal inspection tools within the required reassessment period, and where the operator cannot maintain local product supply if it conducts the reassessment within the required interval. Section 192.943 describes how to seek a waiver if one of these conditions applies.

The below referenced 49 CFR Part 192 sections should help give clarity on the need to take prompt action to address a newly identified threat to a HCA:

  • Section 192.917 combines the threat identification process in 49 CFR § 192.917(a), the data gathering and integration process in 49 CFR § 192.917(b), and § 192.917(c) specifies "an operator must conduct a risk assessment that follows ASME/ANSI B31.8S, section 5, and considers the identified threats for each covered segment. An operator must use the risk assessment to prioritize the covered segments for the baseline and continual reassessments (§§ 192.919, 192.921, and 192.937), and to determine what additional preventive and mitigative measures are needed for the covered segment."
  • Section 192.933(a) requires "an operator to take prompt action to address all anomalous conditions the operator discovers through the integrity assessment. In addressing all conditions, an operator must evaluate all anomalous conditions and remediate those that could reduce a pipelines integrity. An operator must be able to demonstrate that the remediation of the condition will ensure the condition is unlikely to pose a threat to the integrity of the pipeline until the next reassessment of the covered segment."
  • Section 192.933(a)(1) requires a temporary pressure reduction "if an operator is unable to respond within the time limits for certain conditions specified in this section, the operator must temporarily reduce the operating pressure of the pipeline or take other action that ensures the safety of the covered segment."
  • Section 192.933(c) requires "an operator must complete remediation of a condition according to a schedule prioritizing the conditions for evaluation and remediation. Unless a special requirement for remediating certain conditions applies, as provided in paragraph (d) of this section, an operator must follow the schedule in ASME/ANSI B31.8S (incorporated by reference, see § 192.7), section 7, Figure 4. If an operator cannot meet the schedule for any condition, the operator must explain the reasons why it cannot meet the schedule and how the changed schedule will not jeopardize public safety."
  • Section 192.937(b) specifies "an operator must conduct a periodic evaluation as frequently as needed to assure the integrity of each covered segment. The periodic evaluation must be based on a data integration and risk assessment of the entire pipeline as specified in § 192.917." For all gas transmission pipelines, other than plastic transmission pipelines, 49 CFR § 192.937(b) requires "the evaluation must consider the past and present integrity assessment results, data integration and risk assessment information (§ 192.917), and decisions about remediation (§ 192.933) and additional preventative and mitigative actions (§ 192.935). An operator must use the results from this evaluation to identify the threats specific to each covered segment and the risk represented by these threats."

Furthermore, if an operator requests a Waiver as noted in 49 CFR § 192.943, PHMSA would determine during the Wavier evaluation process, as required in 49 CFR § 190.341, if the request for an assessment extension is consistent with pipeline safety.

If we can be of further assistance, please contact Tewabe Asebe at 202-366-5523.


John A. Gale
Director, Office of Standards
and Rulemaking

Regulation Sections

Section Subject
192.939 What are the required reassessment intervals?