Amit_ugcivil
Civil/Environmental
- Sep 27, 2018
- 2
4.5 Line Sizing
4.5.1 Gravity flow piping shall be sized to maintain a minimum flow velocity of 0.9 meters per second (3 feet per second) at the peak flow rate under full flow condition. In no case, the size shall be less than the general requirement stated in para 4.2.29.
Above clause stated In Aramco Design Standard:
1. 0.9m/s velocity shall be maintained considering pipe is flowing full.
2. Actual flow from upstream catchment area generates very much less flow.
3. Hence the for actual flow corresponding actual velocity is much less than velocity @ flowing full.
4.In case of actual velocity is used to satisfy for Vmin=0.9m/s, the pipe slope shall be 1:43
5. Where as for same pipe for Vfull = 0.9m/s the slope is 1:134
My Interpretation is to achieve economy in design the Sewer is designed considering Full Flow(ref 4.5.1) for Vfull = 0.9m/s minimum.
Theoretically the actual flow shall be flowing below 0.9m/s.
please reply is my interpretation is correct:
a) Sewer shall be designed for flowing full Vmin =0.9m/s
or
b) Sewer shall be designed for Actual flow velocity to be at Minimum = 0.9m/s
regards
4.5.1 Gravity flow piping shall be sized to maintain a minimum flow velocity of 0.9 meters per second (3 feet per second) at the peak flow rate under full flow condition. In no case, the size shall be less than the general requirement stated in para 4.2.29.
Above clause stated In Aramco Design Standard:
1. 0.9m/s velocity shall be maintained considering pipe is flowing full.
2. Actual flow from upstream catchment area generates very much less flow.
3. Hence the for actual flow corresponding actual velocity is much less than velocity @ flowing full.
4.In case of actual velocity is used to satisfy for Vmin=0.9m/s, the pipe slope shall be 1:43
5. Where as for same pipe for Vfull = 0.9m/s the slope is 1:134
My Interpretation is to achieve economy in design the Sewer is designed considering Full Flow(ref 4.5.1) for Vfull = 0.9m/s minimum.
Theoretically the actual flow shall be flowing below 0.9m/s.
please reply is my interpretation is correct:
a) Sewer shall be designed for flowing full Vmin =0.9m/s
or
b) Sewer shall be designed for Actual flow velocity to be at Minimum = 0.9m/s
regards