At least through the 2024 PHMSA inspection forms, the hazardous liquids IMP questions had a section of facilities (see definition far below) integrity management questions whereas the gas transmission IMP questions did not. PHMSA still expected that gas transmission operators would address facilities integrity management. Since the code does not specify separate treatment of gas transmission facilities, many operators include them with the line pipe IMP. However, some operators with several gas transmission facilities create a separate facilities integrity management plan. Some of the advantages of this approach per the attached PHMSA collaborative paper on pipeline risk modeling include:
- The concentration of complex equipment at facilities can result in a higher likelihood of failure due to threats like equipment failure and incorrect operation (as shown in historical incident data).
- Equipment failure can be a more significant threat for facilities. Factors such as vibration, excessive and varying temperatures, start-ups and shut-downs, wear, design and construction errors, and other aging/cycling effects affect motive equipment like compressors and pumps and can cause failures of equipment or associated piping.
- Because of the complexity of most pipeline facilities, their failures represent a higher likelihood of service interruption. Standard designs and regulations for facilities include alarms systems, emergency shut-down systems (ESD), site grading for control of lost product, and facility evacuation planning. Most operators employ reliability engineering practices and predictive maintenance schemes to manage facility risk. These factors should be included in the inputs of the facility risk model, as appropriate.
- Facilities that are above ground may be more susceptible than buried assets to some outside force damage threats.
- The operator’s analysis should consider the difference between risks for manned and unmanned facilities.
| Term | Definition | Source |
| Facility | Portions of a pipeline system other than line pipe: includes compressor units, metering stations, regulator stations, delivery stations, holders, fabricated assemblies, and underground storage facilities (gas); and pumping units, fabricated assemblies associated with pumping units, metering and delivery stations and fabricated assemblies therein, breakout tanks, and underground storage facilities (liquid). | 49 CFR Part 192.3
49 CFR Part 195.2 |
Memo: From Attached Pipeline Risk Modeling Technical Information Document 2-1-2020
To support improved facility operation, operators sometimes perform facility reliability analyses. The data and models for such analyses may be used as the basis for facility risk assessments, if they are augmented to include evaluation of consequences to receptors (e.g., human safety and environmental protection) both on and off the facility site. Operators may use tools often applied to analyze the failure of facilities, such as HAZOP, FMEAs, fault trees, LOPA, or “bow-tie” analysis, as a starting point, expanding the analysis to consider failures that have offsite consequences and evaluating the risk of those failures. Operators may also be able to apply the data sets developed for risk assessment for those other tools and analyses.
Wikipedia has a good description of these failure of facilities analysis tools:
- HAZOP: Hazard and operability study – Wikipedia
- FMEAS: Failure mode and effects analysis – Wikipedia
- Fault Trees: Fault tree analysis – Wikipedia
- LOPA: Layers of protection analysis – Wikipedia
- Bow Tie: Bow-tie diagram – Wikipedia
SMEs have told me the above analyses may yield a better description of facility risk than line pipe risk models for facilities.