- *Provide safe access for maintenance and inspection* – they seal the opening to underground utilities (sewers, storm drains, water lines, telecom/electrical ducts) and can be removed so workers can enter or insert tools/cameras for cleaning, inspection and repairs.
- *Protect people, animals and vehicles* – they stop anyone or anything from falling into the shaft and keep the surface flush with roads/sidewalks to prevent accidents.
- *Bear surface loads* – designed to carry traffic loads (pedestrian up to heavy vehicles/docks/airports) and transfer those forces to the frame and surrounding structure.
- *Contain odors, gases and water* – they help seal sewer/storm systems, reducing smell, stopping harmful gases escaping, and limiting rainwater infiltration that can overload drainage.