Setting a Higher Standard for Composite…

Setting a Higher Standard for Composite Manhole Covers

The pop-up problem

Municipalities across the U.S. are increasingly choosing composite covers for their lighter weight and corrosion resistance, according to CAP. Those advantages are clear, but real-world stresses such as heavy loads, long-term vibration and thermal cycles can still lead to instability when design falls short.

In iron, U.S. standards already define what’s acceptable. For composites, there is still no domestic equivalent. By contrast, Europe and Australia have established dedicated standards that account for composite behavior. CAP’s approach is to align with global benchmarks, enabling municipalities to move forward with confidence, knowing their infrastructure meets proven, predictable performance expectations.

How CAP prevents pop-ups

CAP covers are engineered to address the root causes of instability through four key design features:

Center of gravity. Thicker bases — up to four and a half inches in some models — lower the center of gravity, improving ground contact and reducing lift risk compared to thinner, surface-level designs.

Deflection. CAP covers deflect less than 1/2-inch at 50,000 pounds. Some designs start bending at only 16,000 pounds. Reducing deflection eliminates the trampoline effect before it starts.

Warp resistance. Thermoset resin naturally shrinks as it cures. Without ribbing, shrinkage can cause distortion right out of the mold. Internal ribbing reinforces the structure like an I-beam, keeping surfaces flat under both heat and heavy loads.

Hardware. Bolts with 15 full threads — five times more than some imports — provide maximum grip, keeping covers secure even after years of vibration and traffic stress.

These design features demonstrate what future composite standards should require. By applying global best practices and showing what durable, safe performance looks like in the field, CAP is helping move the industry toward U.S. guidelines that emphasize safety, longevity and public trust.

Four engineering details, and one consistent result: a cover that stays put. By engineering for stability, CAP is helping municipalities protect infrastructure today while shaping the stronger, smarter standards of tomorrow.

Composite Access Products services the infrastructure with composite utility access covers. Molded in the company’s McAllen, Texas, plant, CAP’s fast cycle times, with low production costs, allow for affordable, high-quality composite covers competitive to current iron alternatives.