Sewage installations - Bypass ventilation
{TODEL
In many cases of bypass ventilation the internal structure of stacks should be changed. This is achieved by modifying stack data: types of pipes inside, declaration of elements on the top, declaration of internal connections, etc.
The type of the stack is indicated in the Data table.

All necessary points should be specified. Some geometrical data (distances between internal connections) have default values, but these may not fit all cases and often require manual correction after observing the 3D model.
The program provides several schemes of bypass ventilation. Please note, that all changes inside the stack can be achieved only by changing stack data (no graphical edition possible). After drawing and connecting a ventilation pipe-run to a sewage pipe-run, manual correction of the elevations may be necessary.
Sample files with different schemes of bypass ventilation you can find in the article Sewage installations - Bypass ventilation TODEL}
| Product | InstalSystem 5 |
| Type of article | SAMPLE PROJECT |
| Source for translation | 2023-08-21 |
Project description
The attached projects present an exemplary solutions for a sewage installation with bypass ventilation.
Schemes A-D are applicable to buildings from 3 to 5 floors (less or equal to 12m in height). Schema E - for the buildings with more than 5 floors (more than 12m in height).
Schema A
- Direct parallel ventilation: vent stack is connected to the sewage stack at the bottom near the stack foot, and at the top to the vent pipe;
- Generate intermediate ventilation connections can be made or not depending on the project features.

2. Schema A.
Schema B
- Indirect parallel ventilation: vent stack is a separate one, and is connected to the branches on each floor. Horizontal ventilation pipes are to be drawn manually, correcting the elevation where necessary;
- Air admittance valve is used as an Element on top of stack for both stacks (Sanitary drainage and Ventilation conduit).

3. Schema B.
Schema С
- Direct parallel ventilation: vent stack is connected to the sewage stack at the bottom near the stack foot and at the top to the vent pipe;
- Generate intermediate ventilation connections are made;
- Connection to the vent stack from each fixture on the first floor and from each sewage branch on the floors above.

4. Schema C.
Schema D
- Air admittance valve is used on the first floor for the most distant fixture;
- Drainage ventilating pipe-run are connected to the sewage stack on the floors above.

5. Schema D.
Schema E
- In high buildings the fixtures on the lowest floors should be connected to the additional sewage pipe in the stack;
- The additional sewage pipe should be connected to the sewage collector at least 2 m from the base of the stack;
- Generate intermediate ventilation connections is declared as well;
- The connection of the additional stack to the main stack is made by the means of a "vent loop".

6. Schema E.
Files to download and project information
Bypass ventilation Schema A, isproj
Bypass ventilation Schema B, isproj
Bypass ventilation Schema C, isproj
Bypass ventilation Schema D, isproj
Bypass ventilation Schema E, isproj