Manhole – Concentric Cone

Manholes –Manholes are cylindrical hollow concrete structures typically installed vertically below grade. Manholes are an assembly of various components and are then capped at street level with a round cast iron cover.  They are placed at vault openings or pipe junctions and provide maintenance and inspection access to underground piping systems.

Manhole Concentric Cone Components –Concentric cones are typically used with larger diameter manholes and allow for a reduction from a larger diameter to a smaller diameter to match a cast iron cover size. The smaller diameter top opening of the cone is centered on the larger diameter bottom of the cone. Concentric cones are available in a variety of sizes.

Manhole components include:

• Base Unit
• Riser Sections
• Concentric/Eccentric/Slab Tops
• Grade Rings
• Cast Iron Ring/Cover