The gas is also odorized, i.e. a smell is injected into the gas, so that its presence can be detected. It is then drawn out during the cold weather months when it's needed. A compressor station increases gas pressure to move it into storage or through transmission lines. When necessary, pipelines are suspended in the air across canals or attached to bridges. Regulators reduce the pressure of the gas entering the distribution system.
Valves can safely isolate smaller areas during construction and emergencies.
Individual services connect the distribution system to the customer. This document is also available as a 85k file in Adobe Acrobat's .pdf format. If you don't have the free Adobe Acrobat Reader, follow this link to find download information about the freeware version for the type of computer that you work on.