Hydroelectric Penstocks and other water conveyance facilities are typically situated in rural, montane regions where the altitude is optimized to increase head pressure. Inspecting these assets creates innate access and safety concerns due to the rapid sectional altitude changes associated with the penstock location. Historically, operators and engineers walk the steep sections of penstocks with the aid of ropes or make-shift ladders in order to comply with the requirements for inspections and to perform routine checks on expansion joints, foundations and coating integrity. The visual inspections are mandatory but can be accomplished much safer with the use of an Unmanned Aerial System (UAS) and associated Unmanned Aerial Vehicle (UAV).
As a part of the Dam Safety Surveillance and Monitoring Program, owners of Penstocks and Water Conveyance Facilities are required by the Federal Energy Regulatory Commission to create a “Visual Inspection Plan” that outlines the regular inspection intervals for these assets. These guidelines are found in Chapter 14.1 Dam Safety Surveillance and Monitoring Program of the Engineering Guidelines for the Evaluation of Hydropower Projects and are required to be included with the Annual DSSMR Submittal. For more information, please refer to the FERC website regarding the DSSMR. Additionally, inspection intervals may be outlined in the FERC License associated with the forebay and powerhouse.
The FERC is also in the process of developing engineering guidelines that will focus specifically on operation, maintenance, inspection and potential failure mode analysis specific to penstocks and water conveyance facilities. The new guidelines will be found in Chapter 12 of the Engineering Guidelines for the Evaluation of Hydropower Projects.
Inspecting pipelines and related assets connected to the underside of bridges may have been logistically impossible until now. Pipelines that run beside or under bridges cannot be inspected by manual means, and conventional aircraft either are not allowed to fly low enough to see the pipelines or cannot maneuver close enough to get a good view of the asset.
During construction, natural gas pipelines are initially permitted and regulated by the FERC and then oversight is transferred to the Department of Transportation’s Pipeline and Hazardous Material Safety Administration (PHMSA) The PHMSA is responsible for regulating and ensuring safe pipelines across the United States for both industrial and retail customers. The regulations can be found under 49CFR186 et. Seq.
Between 2002 and 2015, 1,138 Compliance enforcement actions have been initiated by the PHMSA against public and private gas pipeline operators across the United States. Through certification by OPS, the state inspects and enforces the pipeline safety regulations for all intrastate hazardous liquid pipelines and for intrastate gas pipelines that are public utilities in California. This work is performed respectively by the California Public Utilities Commission (CPUC) for gas pipelines and by the California Office of the State Fire Marshal (OSFM) for hazardous liquid pipelines.
The CPUC ensures that the state’s natural gas and liquid petroleum gas (LPG) pipeline systems are designed, constructed, operated, and maintained according to safety standards set by the CPUC and the federal government. An inspection report must be filed annually by operators on DOT Form PHMSA F 7000-1.1
Patrolling is a routine inspection of the distribution system. It can be done by walking along the pipeline and observing factors affecting safety of operation (e.g. missing or ineffective meter supports, excessive load on any pipeline component, use of the gas piping for electrical grounding, obstructions in regulator vent, etc.). The gas distribution mains in places or structures where anticipated physical movement or external loading could cause failure or leakage, must be patrolled at least two times each calendar year, but at intervals not exceeding 7-1/2 months. Records of patrolling must be maintained [49 CFR §192.721].