Line Stopping the City of Houston’s Large Diameter Transmission Line for Valve Replacement

A new 72-in. butterfly valve (BFV), replacement of an 84-in. BFV and 84-in. BFV seat replacement were planned to be installed by the City of Houston (City) to improve operational flexibility at a major interconnection serving the Houston Central Business District and the entire west side of Houston. To perform the work, segments of the 72- and 84-in. water lines were required to be isolated and dewatered to accomplish the proposed work. The limits of the shutdown extended past existing interconnections coming off the 84- and 72-in. water lines. An interconnection between the 72- and a 60-in. water line was required to be in service at Emancipation Ave. and Bell St. to maintain the water supply to Downtown Districts. A 72-in. temporary line stop valve was proposed to keep the interconnection in service to meet the water demands and prevent major city-wide impacts to the water system. The 72-in. line stop installation required two attempts to properly insert and stop flow adequately. On the first installation attempt the wings on the folding head needed machining to allow the full circumference to touch the inside diameter of the water line and plug the line. With the line stop installed, the Contractor successfully installed the 72-in. BFV, replaced the 84-inch BFV and internal valve seat with no interruption to the water supply.