Sewer Materials, Shapes, Patterns of Collection System and Appurtenances | SpringerLink
Connections for Ventilation and Venting as well as Lamp Holes | unitracc.com
File:Stone Lamp Hole.JPG - Wikimedia Commons
Sewer Appurtenances In a sewerage system along with pipe lines a number of other structures /devices installations are essential. These devices are provided. - ppt download