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Code of Practice |
10.PUMPED DRAINAGE SYSTEM
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10.1 |
The minimum design and operation criteria for the pumped drainage system shall be as follows:- |
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(a) |
the pumping capacity shall be adequate to cater for immediate discharge of the stormwater ingress of not less than 150 millimetres per hour from the entire source catchment area; i.e: |
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where |
P = pumping capacity (m3/s) |
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I = rainfall intensity (mm/hr) |
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A= catchment area contributing to ingress of stormwater (m2) |
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(b) |
there shall be a complete set of back-up pumping equipment, including back-up pumps, pumping mains, generators and their appurtenances for back-up power supply. |
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(c) |
the pumping installation shall be designed with an automated device to start the pumping operation at times of stormwater ingress, with operational option for manual control to override the automated device whenever desired |
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(d) |
adequate pump sump shall be provided with sufficient storage capacity to cater for the total quantum of inflow from the entire source catchment area over a duration of at least 3 hours or such longer period as may be deemed necessary by the Qualified Person or as required by the Board for the re-activation of the pumping installation in the event of emergency breakdown/repairs or power failure, based on the maximum recorded rainfall given below :- |
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| Duration (hrs) |
3 |
4 |
5 |
6 |
12 |
24 |
| Total Rainfall (mm) |
196.9 |
210.6 |
253.4 |
281.9 |
376.7 |
533.2 | |
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(e) |
the Qualified Person shall formulate and implement a well-regulated procedure for the maintenance, operation and monitoring of the pumped drainage system |
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(f) |
the base of the pump sump shall be designed with a gradient of 1:40 or steeper, and which shall be graded towards the pumps. The pumps shall be located within a small sump pit which should be deeper than the pump sump so that there will be no stagnant water in the pump sump at all times. |
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10.2 |
The criteria specified above are minimum requirements which shall be complied with. Nevertheless, the Qualified Person shall be fully responsible for the complete design of the pumped drainage system, incorporating such additional features or requirements as the Qualified Person may deem necessary to achieve fail-safe protection of the basements, tunnels or underground facilities against flood. |
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10.3 |
The civil and structural components of the pumped drainage system shall be designed and endorsed by a Professional Engineer (Civil) while the mechanical and electrical components shall be designed and endorsed by a Professional Engineer (Mechanical/Electrical). Design computations duly endorsed by the Professional Engineers shall be submitted to the Board for record including the operation sequence and monitoring measures of the pumped drainage system and other relevant information. |
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10.4 |
The developer/owner shall be responsible for the maintenance, operation and monitoring of the pumped drainage system. The Qualified Persons shall liaise with the developer/owner to ensure that a well-established management set-up is operational to undertake this function before applying for the issue of Temporary Occupation Permit and Certificate of Statutory Completion. |
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10.5 |
The Board may in special cases introduce amendments or additional requirements for the design and operation of the pumped drainage systems. | |
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