It is billing time at the city of Evans, Colo., water department. For the past 14 years, Randy, an Evans technician, has devoted days out of every...
Recently in New Orleans, Louisiana, more than two miles of host water transmission main were found to need renewal, especially one portion that required immediate action.
Hobas centrifugally cast, fiberglass-reinforced, polymer mortar (CCFRPM) pipe, approved by the National Sanitation Foundation (NSF) for potable water, made the emergency repair easy and now carries drinking water to New Orleans residents. The recently completed Emergency Water Main Repair project utilized 1,000 feet of 36-inch SN46, PN100 pipe, installed by sliplining an existing 48-inch cast iron line that was nearly 100 years old.
The Sewerage and Water Board of New Orleans chose Hobas pressure pipe for several reasons, including their successful experience on several previous projects in which they had used Hobas Pipe to slipline sewers. Other reasons included Hobas Pipes inherent corrosion resistance and superior flow capacity.
The contractor, Boh Brothers Construction Co. of New Orleans, installed the liner pipes in 10-foot sections. They inserted the entire 1,000 feet by pulling with a winch and cable system from the far end, while also pushing with a backhoe from the insertion point. The pipe sections were assembled with the Hobas gasket-sealed, push-together FWC couplings. The 36-inch OD liner pipe was reconnected at both ends to the 48-inch cast iron pipe using steel reducers with Dresser-style joint seals.
To complete the installation, the contractor filled the residual annular space between the host pipe and liner with 50 pcf grout, placed in one lift. But first, they first filled the 36-inch liner pipe with water to avoid flotation.
The successful installation was confirmed when the new liner pipes passed a three hour, 100 psi pressure test with zero leakage. This achievement convinced the New Orleans Board to include Hobas Pipe in the renewal plans for the remainder of this ancient, cast-iron water main.