The city of Charlottesville, Va., has a population of about 48,000, with 15,000 customers served by 183 miles of piping. The pipe sizes range from 2 inches to 18 inches and are made from a range of materials including galvanized iron, ductile iron, cast iron and high-density polyethylene.
In December 2019, the Department of Utilities was going to replace a mechanical T connection that had 2-inch piping connected to it. To address customer complaints related to low water volume and water discoloration, the utility was going to replace the pipes with 6-inch piping. The utility was looking for a fast, easy way to make the new T-connection installation and replacement while minimizing water shutdown time.
Replacing the existing mechanical T connection quickly and having customers’ water service restored with better water flow presented a unique challenge for Jason McIlwee, PE, the utilities engineering manager for the Department of Utilities.
The utility had used HYMAX products for the last 13 years, including the HYMAX GRIP over the last six years. The HYMAX GRIP T was easier and faster to install compared to the mechanical joint T — each end of the T only had one bolt to tighten compared to multiple bolts. McIlwee and his crew were able to replace the 2-inch piping with the 6-inch piping and insert the GRIP T in about an hour compared to several hours with the mechanical T connection. Both pedestrian and road traffic were minimized, and customers could return to regular water service with reduced disruption.
Ease of Installation
The special HYMAX GRIP chain provided a circular restraint around the pipe, unlike typical wedge-style restraints that point-load and weaken the pipe. As the pipe applies axial pressure, the GRIP chain increasingly tightens around the pipe to prevent pullout. The radial closing mechanism also held the pipes tightly in place during installation to give installers full control over the gap between pipes.
The HYMAX GRIP’s universal gripping system restrains metal and plastic pipes and has a transition capability of up to 1.1 inches. It can work with a wide range of pipe diameters, meaning that Charlottesville’s water utility had extra flexibility to use the GRIP for a variety of other pipe sizes that might be in the ground. By using HYMAX GRIPs instead of mechanical joints, the utility could get the job done faster and spend less time in the ditch to minimize their risk.
“Anytime we can minimize worker time in the ditch is a good thing as it makes for a safer work environment,” McIlwee said. “With fewer bolts to tighten, we could install the T faster, get workers out of the ditch and return water service to customers in less time.”
Durability and Flexibility
The product also offered a whole new level of durability. The GRIP is made of highly durable ductile iron and can withstand a working temperature of up to 125°F. HYMAX GRIP meets or exceeds standards AWWA C219, NSF-61 and NSF-372.
The coupling’s dynamic deflection reduced the risk of damage and cracking due to ground shifts. The HYMAX GRIP’s patented gasket effectively transforms the pipe joint into a flexible connection and allows dynamic deflection of up to 4 degrees per side. The product can also adapt to out-of-round pipe shape (up to 0.16 inch) for optimum fit on both ends with its innovative radial closing design and sealing system that can eliminate installation errors. Even if pipes are just a bit out of alignment, the HYMAX GRIP’s dynamic deflection can still allow for the connection, meaning there’s a smaller chance of mistakes during installation. Overall, these features offer the utility a durable solution that would likely reduce future repairs and maintenance.
The GRIP’s nuts and bolts have advanced anti-galling using a unique dry treatment process with Molecular Anti-Galling (MAG) based on embedded zinc to prevent galling and enable repeated bolt tightening. It also eliminates the need for grease, preventing dust and dirt build-up. The HYMAX GRIP’s fusion-bonded epoxy coating also helps insulate against corrosion.
The HYMAX GRIP T allowed the Charlottesville utility to make necessary repairs in less time, meaning that customers could enjoy the benefits of better water flow sooner with less disruption. Interruptions to road and pedestrian traffic were minimized, and utility workers were able to complete the job with a minimized time in the ditch.
“All things considered, the HYMAX GRIP allowed us to provide better service to our clients and to be as efficient as possible in getting the work done,” McIlwee said. “When it comes to water service and safety, time is of the essence and the GRIP helped on both of those counts.” WW
About the Author: Vince McCaffrey is a territory sales manager for HYMAX with nearly 25 years of experience in the water industry.