SUPPLEMENTARY INFORMATION:

Background

Pipeline risk models are foundational to the assessment of operational pipeline risk. federal pipeline safety integrity management (IM) regulations require pipeline operators to use risk assessments. PHMSA's integrity management regulations (49 CFR part 192, subpart O and subpart P; 49 CFR195.452) require the continual evaluation of threats to pipelines, and evaluation of methods to minimize the likelihood of a release as well as address the consequences of potential releases. Risk models are a primary tool pipeline operators use as part of this evaluation process and are generally referred to as a “risk analysis” or “risk assessment.” A risk model is a set of algorithms or rules that use available information and data relationships to perform a risk assessment. The risk model is a simplified representation of a pipeline system and represents the relation of important risk factors.

To meet integrity management standards, a risk modeling approach must be able to adequately characterize all pipeline integrity threats and consequences concurrently, as well as be able to evaluate the impact of various measures on reducing risk.

In September 2015, PHMSA hosted a public workshop on risk modeling where various comments were presented and discussed with interested stakeholders. Information regarding the previous public workshop can be found at Docket No. PHMSA-2015-0139. Following the public workshop, PHMSA organized a risk modeling work group (RMWG) to gather information regarding state-of-the-art pipeline risk modeling methods and tools; the use of those methods and tools; and the ( printed page 60490) resulting data in operator IM programs. In February 2020, PHMSA issued the resulting report, “Pipeline Risk Modeling, Overview of Methods and Tools for Improved Implementation,” which presented several conclusions:

• The overriding principle in employing any type of risk model/assessment is that it supports risk management decisions to reduce risks.
• While different risk model types have different capabilities for evaluating risk reduction actions, the quantitative system model or probabilistic models are more versatile and provide greater capabilities to provide risk insights and support decision making. Such models are not necessarily more complex nor need more data than other types of risk models.
• Pipeline operators should take ongoing actions to improve and update data quality and completeness over time. However, the type of risk model to employ in pipeline risk analyses should not depend primarily on the perceived initial quality and completeness of input data because all models utilize the available data. Instead, operators should select the best model approach and then populate the model with the best information currently available on risk factors or threats for each pipeline segment and improve that data over time.
• It is important for risk models to include modeling of incorrect operations, which includes human interactions and human performance, that are significant to the likelihood of failure or have a significant effect on consequences of a failure (e.g., inappropriate controller restart of pumps, realistic emergency response time scenarios, design, and construction human errors, etc.).
• It is important for pipeline risk models to include the potential effects of how threats interact in ways that can increase risk. Therefore, when a risk analysis involves multiple threats, the effects of “interactive threats” or dependencies on likelihood of failure should be clearly evaluated.
• Varying levels of sophistication are possible in the analysis of the consequences of a failure. However, it is important to consider an applicable range of scenarios (even if they do not have a high probability of occurrence) to capture the full spectrum of possible consequences.
• The characteristics of pipeline facilities that affect risk may be significantly different than those of line pipe, but the same basic risk assessment principles apply and the same types of models may be applied.

In addition, section 119 of the Protecting Our Infrastructure of Pipelines and Enhancing Safety (PIPES) Act of 2020 directed PHMSA to commission a study to assess regulatory standards and criteria for deciding when automatic and remote-control shutoff valves should be installed on existing hazardous liquid and gas transmission pipelines in high consequence areas (HCAs). The National Academies of Sciences, Engineering, and Medicine (NASEM) conducted the study of potential methodologies for the installation of automatic or remote-controlled shut-off valves and released its findings in February 2024. The study included several recommendations, one of which suggested PHMSA “further the pipeline industry's use of quantitative models for IM risk analysis as well as sound and consistent methods for establishing the benefits of safety measure.” The recommendation specifically includes recommendations to:

• Require the use of quantitative risk modeling by all pipeline operators for their IM programs, except when an operator can make a compelling justification for the use of another risk assessment method.
• Provide the pipeline industry with practitioner-oriented technical guidance for conducting state-of-the-art pipeline risk analyses using quantitative models and for estimating the benefits of alternative risk reduction measures, including public safety benefits and interests.
• Encourage recognized standard-setting organizations, such as the American Society of Mechanical Engineers and American Petroleum Institute, to enhance their standards for hazardous liquid and gas transmission pipelines by including more technical guidance for using quantitative risk models and for obtaining the data needed to develop them.

The 2024 Risk Modeling Public Workshop will provide an opportunity to discuss advances in risk modeling approaches and methodologies for pipeline and non-pipeline systems, as well as practical ways that pipeline operators have adopted and/or adapted methodologies to enhance the risk analyses of their systems.

PHMSA believes that risk models need to evolve in such a way as to be more versatile, thus leading to improved implementation to further reduce the risk of pipeline integrity threats to the public, property, and the environment. PHMSA is particularly interested in improvements to pipeline risk models, and what operators have adopted and/or adapted to risk models as part of the risk analyses of their systems.

Public Workshop and Request for Comments

To this end, PHMSA will hold the 2024 Risk Modeling Public Workshop to discuss and receive public feedback on recent advancements and improvements in risk analyses and risk models. PHMSA invites the public to comment and submit research abstracts on engineering and technical modeling considerations related to advancements in pipeline risk models, as well as risk modeling methodologies used in non-pipeline applications, and practical ways that operators can adopt and/or adapt such methods to the risk analyses of their systems. PHMSA will review all submitted abstracts and may choose to select abstracts for presentation during the workshop.

To be considered for presentation, authors must submit abstracts of 250 words or less to Docket No. PHMSA-2024-0043 by July 30, 2024. If selected, PHMSA will notify the author of their selection by August 30, 2024. Each author of a selected abstract will then provide a short presentation to be used during the workshop. This will be due by September 30, 2024.

Specific examples of applications are encouraged. PHMSA is interested in engineering and technical modeling considerations, including, but not limited to, the following:

• Quantitative system and probabilistic risk approaches;
• Treatment of human performance, including both likelihood and consequence aspects;
• Consideration of threats and their interactions in risk assessments;
• Modeling challenges associated with the transportation of hydrogen, hydrogen blends, or carbon dioxide;
• Identification, evaluation, and comparison of preventive measures and mitigative measures;
• Cost/benefit analysis for risk reduction options; and
• Continual evaluation of integrity and general risk management decision making.

PHMSA is not always able to publish a notice in the Federal Register quickly enough to provide timely notification of last-minute changes that impact scheduled workshops. Therefore, individuals should check the workshop website listed in the ADDRESSES section of this notice or contact Lee Cooper by phone at 202-913-3171 or by email at Lee.Cooper@dot.gov, regarding any possible changes. PHMSA invites public participation and public comment on the topics addressed in this public ( printed page 60491) workshop. Please review the ADDRESSES section of this notice for information on how to submit written comments.

89 FR 60489