Gravity Sewer Systems
A  Building Drainage Drainage system As no two projects are the same in terms of local conditions and drainage requirements, no standard formula can be given for building drainage design. Certain general key principles do, however, apply to the design of drainage systems as a whole.
The purpose of the drainage fill (see Figure 5.9.6) is to convey water to the drainage pipes. For the system to function, it is essential that the drainage fill forms a continuous layer in direct contact with the drainage pipes. The drainage system is designed to function by gravity.
Drainage systems for building foundations comprise a filter layer and/or filter fabric, drainage gravel and drains.
The system can be supplemented with watertight structures and materials that improve drainage efficiency.
The purpose of the filter layer is to maintain drain function by preventing fine material from entering the drain.
Drainage around buildings
Figure 5.9.6 Uponor Drainage Systems
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