The pipeline transportation of natural gas in the Northern Tier Region occurs in gathering, transmission, and distribution pipelines. These lines are both inter and intra-state pipelines.
Examples of gathering lines are pipelines that run through the gas fields, the gas gathering area, perhaps 6” in diameter to as much as 30” in diameter. These lines are high pressure pipelines. A high pressure line is generally any line that is in excess of 100 psi. The lines in the gathering fields presently are running at pressures of 1,000 psi or more. The specified pipeline of choice is generally that of 1,440 MAOP [maximum allowable operating pressure] in the gathering fields. Generally, pipelines are pressure tested to pressures in excess of the MAOP to ensure safety and operability. A gathering line may be of less than one mile in length to thirty or more miles and is travels a route to the nearest transmission line.
Examples of transmission lines in the Northern Tier Region are the Tennessee and Marc 1 Hub pipelines. The Transco operates to our south, and gas from both gathering lines and the Marc 1 Hub pipeline is routed to south to the Transco pipeline. These transmission lines are 24” diameter and greater.