Case Study: Unforeseen Shock Hazards from Code Compliance at an Above Ground Pipeline Valve Station

The Code of Federal Regulations (CFR) is a regulatory collection of general and permanent rules of federal agencies. This case study is specific to two sections pertaining to the control of corrosion and electrical protection of underground pipe lines and valve stations. The transportation of hazardous liquids is covered by 49 CFR 195, and the transportation of natural gasses is covered by 49 CFR 192. A method of meeting compliance is with the installation of devices and systems to electrically isolate a cathodically protected pipe line and valve stations from nearby grounded structures and equipment. This case study focuses on an industrial installation where a worker was inadvertently exposed to higher than expected voltages after the installation of the required isolation devices.