a) Two pipe system
In this system two pipes are provided. One pipe collects the foul soil and lavatory wastes, where as the second pipe collects the waste water from kitchen, bath rooms, house washings, rain water etc. The soil pipes are directly connected to the drain, whereas the waste pipes are connected through the trapped gully. All the traps used in this system are fully ventilated.
b) One pipe system
In this system only one pipe is provided which collects both the soil waste as well as waste from the building. The main pipe is directly connected to the drainage system. In multi – storeyed buildings the lavatory blocks of various floors are so placed and arranged that the waste water discharged from the different units can be carried through common vertical stacks. Connected through short branch drains. All the traps are fully ventilated, but all the gully traps and waste pipes are completely dispensed with.
c) Single stack system
This system is similar to the single pipe system, the only difference being that no ventilation is provided even in the traps too.
d) Single stack partially ventilated system
This is a via media between the one pipe system and the single stack system. In this system only one pipe is provided to collect all types of waste water. A relief vent pipe is provided which ventilated only the traps of water closets.
Choice of system
The two pipe system of plumbing is safer than other systems of plumbing. It provides an ideal solution where it is not possible to fix the fixtures closely.
The one pipe system is economical as all types of waste waters are collected in a common sewer line to the place of disposal.
The single stack system, which also serves as a ventilating pipe is being used now a days. This system can be used for buildings upto five storeys for buildings with 100 mm dia stack. Not more than two toilet units can discharge into the single stack ast each floor.
