Tested for deflection
It is very difficult to look at a composite access cover and know how it will perform over time and under repeated heavy wheel loads.
Many composite access covers look similar, yet perform differently, some leaking or even breaking after cyclical loading. Like any highly engineered product, the cleverness is hidden inside. Composite covers are no different.
The simplest way to measure this is by level of deflection.
Here Fibrelite test its and a competitor’s cover.
Excessive deflection indicates a lack of stiffness and potentially leads to fatigue and premature failure in manhole covers.
Repeated deflection beyond the elastic limit results in permanent deformation. Permanent deformation presents safety issues with rain water pooling on the manhole cover, the cover no longer seating correctly within the frame and ultimately failure.
