Pipeline transport in order to avoid melting the frozen ground by hot petroleum which would result in sinking the pipeline in the ground. Maintenance of pipelines includes checking cathodic protection levels for the proper range, surveillance for construction, erosion, or leaks by foot, land vehicle, boat, or air, and running cleaning pigs, when there is anything carried in the pipeline that is corrosive. US pipeline maintenance rules are covered in Code of Federal Regulations(CFR) sections, 49 CFR 192 for natural gas pipelines, and 49 CFR 195 for petroleum liquid pipelines. In the US, onshore and offshore pipelines used to transport oil and
CLH Pipeline System the WW2 cross-Pennine pipeline was found to be badly corroded and in the 1950s a new pipeline was built from the Stanlow area to the Humber. New storage depots were built on this pipeline and a third new import facility was constructed on the Humber. The first commercial usage of the system was immediately after the war to supply a depot on the River Severn from Avonmouth. In the early 1950s some aviation fuel was pumped from Avonmouth to a depot on the Thames to supply Heathrow airport by road tanker from there. Esso also used the network to pump