Assessment of Free Water Flow at a Gas Pipeline Dead Leg/Lateral InterfaceX. He K. Supak R. Owston S. Stothoff and K. DasSouthwest Research Institute®In the oil and gas pipeline industry one way to achieve continued flow while replacing a section of pipe is to introduce a stopple and insert a bypass. However this process creates two flow?dead legs which are segments of the original pipeline typically several pipe diameters long with capped terminations. With the implementation of the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) Rule 49 CFR 192.476 Internal Corrosion Control: Design and Construction of Transmission Line a concern arose with respect to the possibility that any liquid water that might exist within the dry gas pipeline might be collected in the flow?dead leg pipe segments and cause internal corrosion compromising operations and public safety. The PHMSA Rule requires the pipeline operator to minimize the number of dead ends to reduce the risk for liquids to collect in the line. Both experimental flow testing and computational fluid dynamics simulation of liquid and gas two phases were conducted to evaluate free water division in the dead leg and lateral path. This paper will focus on presenting the results from experimental testing which demonstrates there is a maximum liquid flow rate bypassing the dead leg and flowing down the lateral path at a given gas flow rate. In the event water enters the dead leg the experimental testing shows that complete liquid removal is not possible even with high gas sweep rates with droplets remaining as well in the inlet and lateral path.