The purpose of the sanitary system in a building is to supply fresh water into the building and remove waste water from the building.
It is the stack’s duty to collect wastewater from toilets, kitchen and other watering areas and carry the wastewater to the discharge point.
As stacks run vertically in a building, it is also called vertical stack.
So, What are stacks?
What is a Stack of The Sanitary System in a Building?
Stacks are some pipes which are placed vertically in a building for the purpose of removing wastewater from the watering area of a building.
Stacks are normally collect wastewater from the trap and carry the liquid to the discharge point.
We normally use uPVC pipes for stacks. There are some other types of pipes are also used for this purpose.
To successfully discharge water, we use various types of stacks in a building.
So, What are the types of stacks used in a building?
Types of Stacks of Sanitary System in a Building
To successfully discharge waste from toilets, we mainly require three types of the stack in a building – Soil stack, Waste Stack, and Vent Stack.
Besides these, we also need another stack, that is Rainwater Stack.
Let’s discuss all the stacks separately.
Soil stack is used to discharge waste from commode and urinals only. No other wastewater is discharged through this stack.
We normally use 4 inches diameter uPVC pipes as soil stack.
This stack runs vertically near the toilets of a building for the purpose of collecting wastewaters from commode and urinals.
When soil stack is installed, a “Tee” is kept on every floor of the building to connect the stack with the branch pipes of toilets.
A waste stack is also a vertical pipe which is also used to discharge wastewater from toilets and kitchens.
A Waste stack and a Soil stack is the same thing and work the same way. The only difference between two is soil stack discharge wastewater from commode and urinal only whereas, a waste stack discharge wastewater from basins, showers, sinks, etc (without commode and urinals).
A waste stack is also installed vertically along the building near the toilets. We normally use 4 inches diameter uPVC pipes for waste stacks.
While installing a Waste stack, a “Tee” is kept on every floor to connect to the branch pipe of a toilet.
If you have ever tried to pour water from a bottle, you may have seen water can’t be poured easily from the bottle.
This happens because when you try to pour water from the bottle, air needs to enter into the bottle.
The same thing happens when wastewater flows through the Soil stack or Waste stack. If the air won’t flow through the stacks, wastewater flow is interrupted.
To get rid of this situation, a Vent stack is provided connecting both Soil stack and Waste stack.
A Vent stack serves two facilities to the Soil and Waste stack. One is to allow air to the soil and waste stacks and another is to remove odor gas from the stacks.
Rain Water Stack (RWS):
Form the name of this stack, you already get the idea what it is.
A Rainwater stack discharges rainwater from the roof of a building.
This is also a vertical stack which runs vertically along the building allowing rainwater flow freely through it from the roof to discharge point.
We normally use 4 inches diameter uPVC pipes for this purpose.
There is some other rainwater need to be discharged from the building. Such as rainwater from veranda or balcony.
We normally use 2 inches diameter uPVC pipes for removing rainwater from veranda or balcony.
Stacks are an important part of a sanitary system in a building. These need to be properly designed to discharge the wastewater from the building.
As a construction professional, we also need to be careful installing soil, waste and vent stacks in a building. So that, wastewater can flow freely through the stacks.
Share Your Expertise
Which size and type of pipes do you use for sanitary stacks? Please share in the comments below…