The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

How To Design And Install Plumbing

Looped ventilation is not deemed practical and it should be resorted to only when other methods of ventilation are not applicable. It is, however, the best that can be accomplished under certain circumstances and its use should not be too restricted.

Sizing the Looped Vent. Looped vents generally are of the same design as individual vents and are sized in the same manner.

Looped Vent Installation. Fig. 173 illustrates how a lavatory located in the center of a room may be loop-vented. The fixture in the illustration is back-vented. The vent pipe is extended vertically to the partition and reconnected into the main vent a few inches above the top rim of the fixture it serves.

A full size bleeder or drip connection must be made between the waste pipe and the lowest point of the vent line to permit any accumulation of water to drain from the trapped looped vent.

Local Vent. A local vent has no connection with the plumbing system. It may be defined as a conduit or pipe shaft used to convey the foul odors from a fixture or room. It is used to some extent in connection with water closets, and is connected to the fixture at a point below the seat. It terminates at the roof. Fig. 174 illustrates an installation of this kind.

Rooms which have no natural ventilation generally are provided with a local vent. Pipe constructed of sheet metal is used for this purpose.