The Client

Mark Edwards is the repair supervisor for Grand Strand Sewer & Water Authority, a utility that serves approximately 90,000 customers in Horry, Marion, and Georgetown counties in South Carolina and Columbus county in North Carolina. The area’s water and sewer infrastructure contains a wide variety of pipes made from PVC, ductile iron, steel and asbestos-cement (AC) in many sizes. The pipes also differ considerably in age with some of them dating back 60 years or more.

The Situation

In early 2017, Edwards was alerted to an AC pipe that broke, most likely due to shifting ground cause by cold winter weather. The pipe required a section to be cut out, replaced by PVC pipe and connected with two 8-inch couplings. He needed to join two pipes of differing materials, and needed a coupling that could quickly make the repair.

The Challenge

Edwards wanted to minimize down time to ensure that water service was returned quickly. He also wanted assurances that the repair would be permanent and last in the long-term.

The Solution

Edwards decided to connect the AC pipe with the HYMAX 2 coupling. A new version of the original HYMAX, the HYMAX 2 has a no-tear flip gasket that can be adjusted to fit both larger and smaller pipe outside diameters and ensures an efficient installation.

Edwards used a chain break cutter to cut out the damaged section of pipe, which allowed for it to break cleanly and avoid environmental risks. The HYMAX 2 is a stab-fit coupling which helped enable faster and safer installation of the coupling. With the section cut out, the crew slid on two HYMAX 2 couplings onto the PVC pipe, put in place between the AC pipe, and tightened the couplings quickly with its two top-facing bolts. The entire repair took less than three hours to complete.

The coupling has a working pressure of 260 psi, and meets or exceeds standards AWWA C-219, NSF 61 and NSF 372. The center ring is made of grade A steel with the end ring made of grade C steel. The gaskets are EPDM which is compounded for water and sewage and meets international standards for contact with drinking water. The bridge is made of stainless steel while the coupling is coated with 100% fusion bonded epoxy for enhanced corrosion protection. Nuts and bolts are also made of stainless steel with a rolled thread and go through a unique dry treatment process, Molecular Anti-Galling (MAG), based on embedded zinc. MAG technology eliminates the need to grease bolts and the effects of dirt and sand, preventing galling and enabling repeated bolt tightening.

There were five reasons why Edwards went with the HYMAX 2.

1. HYMAX’s Reputation

After years of experience using different repair couplings, Edwards had found that HYMAX couplings were the most reliable and the easiest to install. “We had a number of experiences with other couplings but we found that HYMAXs just worked the best,” said Edwards. “Some people use the HYMAX’s for exceptional circumstances but we found that the ease of installation and wide-range made it worthwhile to have in standard supply at our warehouse with couplings ranging from 2 to 12 inches.”

2. Easy to install/Increased Safety

The HYMAX2 has only two top-facing bolts to tighten which allowed Edwards’ crew 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 to help minimize safety risks. The HYMAX 2 is also lightweight which further allows for easy installation with minimum manpower.

3. Exceptionally Wide Range

HYMAX 2s have an exceptional range of 1.3 inches and can connect pipes for a variety of different materials. Compared to other couplings, which are range-dedicated and limited to a single pipe size, installers have much greater flexibility to make repairs as they uncover pipes in the ditch.  

4. High Durability

The HYMAX 2 is very durable and offered a long-term repair solution. It can absorb post-installation dynamic pipe deflection of up to 4° on each end to absorb pressure on the pipe due to shifting ground and changing temperatures. The deflection helped reduce the risk of damage and cracking while saving resources on constant future pipe repairs. The patented hydraulically-assisted gasket features two-stage sealing: mechanical sealing that is effective under vacuum or non-pressure; and self-inflated gasket using water pressure.

5. Cost Savings

HYMAX 2 products suit a wide range of pipe diameters, replacing the need to use dedicated products and reducing inventory costs and shelf space. “Maintaining inventory with the right products for the repair is easy when stocking HYMAX couplings,” said Edwards. “If there’s a repair that needs to be made, a HYMAX will take care of it without taking up too much space in our warehouse.”


The HYMAX 2 offered many advantages to help Edwards make the repair. The product’s no-tear flip gasket allows installers to more efficient installations, and easily adjust the gasket’s size as required. The HYMAX 2 is also durable with its dynamic deflection to help absorb stresses caused by shifting ground. With its two top-facing bolts, workers did not have to dig under the pipe to tighten bolts and could be installed fast to minimize time in the ditch to help ensure worker safety. Finally, the capacity of the coupling to fix a wide range of piping materials and outside diameters allowed to minimize inventory space and reduce costs.