Sewers
Definitions.—A sewer is a conduit or pipe intended for the passage of sewage, waste, and rain water.
A House Sewer is the branch sewer extending from a point two feet outside of the outer wall of the building to its connection with the street sewer, etc.
Materials.—The materials from which sewers are manufactured is earthenware "vitrified pipes."
Iron is used only for pipes of small diameter; and as most of the sewers are of greater diameter than six inches, they are made of other material than iron.
Cement and brick sewers are frequently used, and, when properly constructed, are efficient, although the inner surface of such pipes is rough, which causes adherence of sewage matter.
The most common material of which sewers are manufactured is earthenware, "vitrified pipes."
"Vitrified pipes are manufactured from some kind of clay, and are salt-glazed inside. Good vitrified pipe must be circular and true in section, of a uniform thickness, perfectly straight, and free from cracks or other defects; they must be hard, tough, not porous, and have a highly smooth surface. The thicknesses of vitrified pipes are as follows:
| 4 inches diameter | 1/2 inch thick |
| 6 " " | 1/16 " " |
| 8 " " | 3/4 " " |
| 12 " " | 1 " " |
The pipes are made in two- and three-foot lengths, with spigot, and socket ends." (Gerhardt.)