This document is the 2' x 2' & 2' x 3' Curb Inlet Structure Specifications Detail. It explains engineered surface drainage products.

In general, PVC surface drainage inlets shall be of the curb inlet structure type as indicated by the drawings and plan. The ductile iron frame, grate and hood is integral to the surface drainage inlet and shall be provided by the same manufacturer.

Materials shall be manufactured from PVC pipe stock, utilizing a thermo-molding process to reform the pipe stock to the configuration. The drainage pipe connection stubs will be manufactured from PVC pipe stock and formed to provide a watertight connection. The joint tightness shall conform to ASTM D3212. The flexible elastometric seals shall conform to ASTM F477. The pipe bell spigot is to be joined to the main body. The raw materials used to manufacture the pipe stock, main body and pipe stubs shall conform to ASTM D1784.

The grate, frame and hood for all curb inlet structures shall be ductile iron and made with a round bottom flange that closely matches the diameter of the PVC basin body. The grate, frame and hood shall be capable of supporting H-20 wheel loading for traffic areas. The hood section will have a solid back and be adjustable. The metal used in the manufacture of the castings shall conform to ASTM A536 grade 70-50-05 for ductile iron.

Installation shall use the specified PVC surface drainage inlet using conventional flexible pipe backfill materials and procedures. The backfill is crushed stone or other granular material. Bedding and backfill shall be packed uniformly. The curb inlet structure body will be cut during final grade. No brick, stone or concrete will be required to set grate to final height. For H-20 load rates installations, a concrete ring will be poured under the grate, hood and frame. The concrete slab must be designed per local soil conditions, traffic load and other factors.