A manhole cover may fit an opening perfectly and still be the wrong cover for the job.
One of the most common specification considerations is the load the cover will be expected to withstand. A cover installed in a pedestrian environment faces very different demands from one positioned near vehicular traffic, along a roadway or within an industrial site.
Understanding load classifications can help specifiers and contractors select a cover that is appropriate for its intended location.
What does a manhole cover load rating mean?
A load rating indicates the level of loading a manhole cover and its associated system are designed to withstand under specified conditions.
Under classification systems such as EN 124, access covers are grouped into different load classes according to their intended application.
The important point is that manhole covers are not selected by dimensions alone. Location, expected traffic and anticipated loading must also be considered.
Understanding common load classes
Three classifications that may be encountered across construction and infrastructure applications are:
B125: Typically associated with lighter-duty applications where loading requirements are lower.
C250: Used for applications requiring greater load capacity and where vehicular loading may need to be considered.
D400: Designed for more demanding applications associated with roadways and regular vehicular traffic.
The correct classification should always be determined according to the project’s specific location, loading conditions, applicable standard and installation requirements.
What happens when a cover is incorrectly specified?
Selecting a cover below the required load classification can expose it to forces beyond those for which it was designed.
Over time, this can increase the risk of:
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- damage or deformation;
- premature deterioration;
- movement or instability;
- increased maintenance;
- potential safety concerns; and
- premature replacement.
Overspecification can also be unnecessary. The objective is not automatically to select the highest available classification, but to specify the appropriate system for the application.
Look beyond the cover itself
The cover is only one part of the installation.
The frame, supporting structure and installation conditions can all influence how the complete system performs. A correctly rated cover cannot compensate for an unsuitable or poorly executed installation.
Specification should therefore consider the complete assembly rather than treating the cover as an isolated component.
Questions to ask before specifying a manhole cover
Before selecting a cover, establish:
- Where will it be installed?
- Will pedestrians, passenger vehicles or heavier vehicles pass over it?
- How frequently will it experience traffic?
- What loads are anticipated?
- What load classification is required?
- What installation conditions must be accommodated?
- Which applicable standards or project specifications must be followed?
- Answering these questions early can help prevent an unsuitable product from reaching the installation stage.
Fiberpol Infrastructure supplies manhole cover solutions across different load classifications for drainage, access and infrastructure applications. Our team can help customers identify solutions based on the intended application and project requirements.
Need help determining which manhole cover is appropriate for your application? Speak with Fiberpol Infrastructure.