Following are the four main systems adopted in plumbing of drainage work in a building.

1. Single stack system

2. One pipe system

3. One pipe system partially ventilated

4. Two pipe system

1. Single stack system

In single stack system a single vertical soil pipe is fixed and all the waste matter from baths, kitchen, water closet etc. its discharge into it.

This pipe is addition also act as vent pipe.

This system is economical, but it effectiveness entirely depend upon the water seal.

Therefore the water seal in traps should not be less than 75mm.

2. One pipe system

In this system a separate vent pipe is added in addition to waste collection pipe hence tis method is more effective than the single stack system.

The vent pipe provides ventilation to the water seals of the entire trap.

The main pipe is directly connected to the drainage system.

If this system is provided in multi-storeyed building the WC block of various floor are placed one over the other.

Advantages of one pipe system

1. The system is intermediate arrangement between the one pipe system and single stack system.

2. In this system there is one soil pipe and all the waster matter from water closets, bath, sink etc. is discharge in this pipe.

   

3. One pipe system partially ventilated

The system is and intermediate arrangement between the one pipe system and single stack system.

In this system there is one soil pipe and all the waster matter from water closets, bath, sink etc. is discharge in this pipe.

The vent pipe provided ventilation only to trap of water closets.

4. Two pipe system

In this system two set up of pipe are laid.

One pipe i.e. soil pipe is connected to the soil fixture such as urinal and water closets.

Another pipe i.e. waste water pipe is used to collect the waste matter from bath kitchen etc.

The soil pipe and waste pipe provided with separate vent pipe.

It will require four vent pipe and hence it become costly.