Development of the “Gray-Buster-Advance Lining” method for renovation of gray cast-iron pipes

The Gray-Buster-Advance Lining (GBA) method for the renovation of gray cast-iron pipes has been developed. In general, gray cast-iron pipes installed in the past are prone to be broken by ground subsidence. The breakage of these pipes must be prevented in order to reduce the risk of gas leak accidents. This GBA method can form a thick synthetic resin membrane inside the pipes without the need for excavation, and can make the pipes as robust as new pipes.In addition, a remarkable feature of this method is that re-connection work of branching lateral pipes is not needed because blocking of branch points by the resin membrane can be avoided by blowing air from the end of the service lateral pipe during the resin lining process. Therefore, the construction cost for digging, filling and re-paving can be reduced compared with conventional methods such as the pipe-in-pipe method.In this paper, the characteristics and procedure of the GBA method and advantageous points compared with conventional methods are described.