Across North America, public works departments and municipalities are facing a growing challenge: deteriorating concrete grade rings that allow inflow and infiltration (I&I) into wastewater systems. While concrete rings have been the industry standard for decades, they were never designed to last forever—or to withstand today’s harsh environmental conditions. As systems age and exposure to road salt, chemicals, and hydrogen sulfide increases, concrete rings crack, crumble, and ultimately fail.
PRO-RING adjustable grade rings were developed to solve these long-standing problems. Made from expanded polypropylene (EPP), PRO-RINGs offer a modern alternative to concrete—one that is lighter, stronger, longer-lasting, and far more effective at stopping I&I.
Why Concrete Grade Rings Fail
Concrete grade rings are highly susceptible to environmental and mechanical stress. They can crack during transport, fracture when handled, and deteriorate due to prolonged exposure to road salt, deicing chemicals, and hydrogen sulfide gas. Mortar joints and shims—commonly used to achieve proper elevation—create additional weak points where water can infiltrate.
Once deterioration begins, concrete rings often allow groundwater, stormwater, and snowmelt to enter the collection system. This added flow increases treatment costs, strains wastewater treatment plants, and diverts valuable time and resources toward repeated repairs. With a typical service life of just 5 to 25 years, concrete rings often require multiple replacements over the life of a manhole.
Built to Last: The PRO-RING Advantage
PRO-RINGs are manufactured from expanded polypropylene (EPP), a high-strength, energy-absorbing plastic known for its exceptional durability and strength-to-weight ratio. Unlike concrete, EPP is corrosion resistant and unaffected by road salt, chemicals, or hydrogen sulfide. PRO-RINGs will not crack, crumble, or deteriorate over time—and they can withstand millions of impacts without fracturing.
From a structural standpoint, PRO-RINGs meet or exceed AASHTO HS-25 load requirements and are designed for a 100-year service life. They also meet or exceed ASTM C1244 vacuum testing requirements and ASTM C969 infiltration/exfiltration standards, ensuring a tight, watertight seal that concrete rings simply cannot maintain long term. This durability is backed by a 25-year material warranty, providing confidence well beyond traditional concrete solutions.
Superior Protection Against Inflow and Infiltration
Stopping I&I requires eliminating weak points—and PRO-RINGs do exactly that. Unlike concrete systems that rely on mortar and shims, PRO-RINGs create a continuous, infiltration-proof adjustment system. They will not leak, even as surrounding infrastructure shifts or settles.
By preventing stormwater and groundwater from entering the system, PRO-RINGs help reduce peak wet-weather flows and lower operational costs at wastewater treatment plants. Over time, these reductions translate into significant savings and improved system performance, especially during heavy rain events and snowmelt.
Faster, Lighter, and Safer Installation
One of the most immediate advantages of PRO-RINGs is their weight—or lack of it. PRO-RINGs weigh approximately 1/20th as much as concrete grade rings, making them easy to handle without cranes or other heavy equipment. This significantly reduces labor requirements, installation time, and the risk of worker injuries.
The lightweight design also leads to fewer workers’ compensation claims, lower shipping costs, and reduced equipment purchases, storage, and maintenance. Because no heavy machinery is required, road closure times are shortened—minimizing traffic congestion, reducing emissions from idling vehicles, and improving safety for both workers and the public.
PRO-RINGs are also far less prone to damage. While 10–20% of concrete rings may arrive cracked or break during transport and handling, PRO-RINGs will not fracture if dropped, resulting in less waste and fewer delays on the job site.
Precision, Flexibility, and Long-Term Value
PRO-RINGs allow adjustments to within ¼ inch of the desired final elevation—without mortar, shims, or grinding. They are available in thicknesses ranging from ¾ inch to 6 inches, as well as tapered options, making them highly adaptable to miscalculations or unforeseen field conditions. Unlike concrete, PRO-RINGs have no stacking height limitations, reducing additional construction costs when greater vertical adjustment is required.
From a lifecycle perspective, the value is clear. Over 100 years, a single PRO-RING can replace the need to remove and reinstall 4 to 10 concrete rings. When factoring in labor, equipment, traffic control, and wastewater treatment costs, PRO-RINGs deliver substantial long-term savings.
A Smarter Solution for Today’s Infrastructure
Concrete rings were never intended to withstand modern environmental stressors—or to provide permanent protection against I&I. PRO-RINGs were. Their unmatched durability, corrosion resistance, lightweight design, and watertight performance make them a superior solution for municipalities looking to solve I&I challenges once and for all.
In short, PRO-RINGs are faster to install, lighter to handle, safer for crews, and designed to perform for a full century. To learn more about additional advantages—or to see the benefits firsthand—we invite you to request a free product demonstration. Work directly with our team, experience the PRO-RING system in action, and take a meaningful step toward eliminating inflow and infiltration in your community.