By Vince McCaffrey
Mike Strader is the construction and maintenance supervisor for the City of Greensboro, North Carolina (population roughly 295,000). The city’s water infrastructure is made up of 1,500 miles of public water mains with 33,000 valves and 15,000 hydrants. Most of the pipes are constructed with cast iron, ductile iron and PVC.
The utility discovered a leak on a lead joint on a water main that was feeding into a water tower. A section of pipe needed to be cut out and the utility discovered it was made of cast iron and installed nearly 100 years ago. Its outside diameter was 26.3 in. and neither a solid sleeve nor dresser coupling would fit to connect to the smaller sized ductile iron pipe. To avoid disrupting water service, the water tower would need to be reconnected within 48 hours.
The utility chose to use a 24-in. HYMAX long-body (18 in.) coupling which could connect the unusually sized 26.3-in. cast iron pipe and the 24-in. ductile iron pipe. While the coupling was on its way, the utility cut out the section of pipe to enable quick installation for when the coupling arrived. The long-body coupling offered more wiggle room to adjust the fitting compared to the standard-length version, and was installed within 30 minutes with only four top-facing bolts to tighten.
“The HYMAX large diameter (HLD) was much easier to connect compared to a sleeve, given there are only four bolts to tighten,” said Strader. “We were lucky to find a coupling that had the range to connect the two sizes of pipe. Without this long-body coupling, we would have had to get a customized solution which could have easily taken four to six weeks to arrive.”
There were four main benefits to using the HLD.
The unique design features of the large diameter coupling enabled the City of Greensboro to connect the 100-year-old cast iron pipe and the ductile iron pipe within the required time.
Exceptionally Wide Range Connects Different Sized Pipes
HLDs have an exceptional range of 2.1 in. which can connect pipes for a variety of different materials. Compared to other couplings, which are range-dedicated and limited to a single pipe size, the utility had the flexibility to connect the 26.3-in. cast iron pipe to the ductile iron piping. Other couplings don’t have as much leeway with deviation in size or if the shape of the pipe isn’t perfectly round. The coupling was installed easily despite the different sizes of connecting pipe and can even connect to oval-shaped pipes with a strong, secure fit.
Speedy Installation with Only Four Top-facing Bolts to Tighten
Compared to as many as 14 bolts in other 24-in. couplings, the HYMAX coupling has only four top-facing bolts to tighten. This enabled the utility to install the coupling quickly without digging under the pipe for space to tighten the bolts. With fewer bolts to tighten, crews spend less time in the ditch which helps to minimize safety risks.
“Getting under the pipe to tighten bolts is hard because there is less leverage to tighten bolts compared to being on your feet,” said Strader. “That’s less wear and tear on workers’ bodies too.”
Ease of Installation with One-piece, Stab-on Design
HYMAX couplings have a one-piece, stab-on design which is simpler to install compared to other large couplings which require assembling many different parts. The chances of complications occurring are higher when more parts are involved and can lead to delays and complications such as losing bolts in the mud. The long-body version of the coupling (18 in.) also offered more flexibility to adjust the fitting than the standard length (11.6 in.).
The long-body coupling offered more wiggle room to adjust the fitting compared to the standard-length version, and was installed within 30 minutes with only four top-facing bolts to tighten.
Durable, Dynamic Deflection Minimizes Breakage
This large diameter coupling is durable and offers a long-term repair solution. It can absorb post-installation dynamic pipe deflection of up to 4 degrees on each end to absorb pressure on the pipe due to shifting ground and changing temperatures. The deflection will help reduce the risk of damage and cracking while saving resources on future pipe repairs.
These unique design features of the large diameter coupling enabled the City of Greensboro to connect the hundred-year-old cast iron pipe and the ductile iron pipe within the required time.
“It was great that we were able to make the repair quickly without the need for a customized part,” said Strader. “We know that this connection will last over the long haul, and we’ve since stocked our warehouse with HYMAX HLDs to give us the flexibility to quickly repair large pipes, regardless of its size or material composition.”
Vince McCaffrey is HYMAX territory sales manager for Mueller. He serves several U.S. Mid-Atlantic states and previously worked for Master Meter where he also served extensively in the mid-Atlantic region.
