Drainage Designs

Building Down-take pipe design

1. calculate terrace area A = Terrace area (m²)
2. take reference of R = Rainfall intensity (mm/hr)
3. based on surface adopt C = Runoff coefficient
4. Q= (AxRxC) Runoff Quantity in litres per hr 
5. arrive liters/sec = Q/3600.
6. Dia of down-takes
7. CSA of each downtake in sqm [A]
8. No of down-takes
9. Gravity (mt/sec) 9.81
10. Head / height of structure in mts
11. Velocity  [V]  (mt/sec) = Gravity x Height 
12. Q = A x V x 1000 (litres/sec)