QP is required to check and confirm that there are no other lateral connections to the sewers/common sanitary drain-lines/drain-lines which are to be abandoned. The QP shall submit a plan to PUB, Building Plan Division (BPD) showing the sewerage system to be discontinued or closed up for approval.
The sewer proposed to be abandoned shall not be sealed off until the new sewer has been completely inspected and certified fit for use and the flow diversion work is completed. PUB’s approval shall be obtained before carrying out the sealing works.
QP shall arrange with Mr Muhd Nabil Raus (Muhd_Nabil_Mohd_Raus@pub.gov.sg) or Mr Qin Yihuai (QIN_Yihuai@pub.gov.sg) of PUB’s Network Management Branch (NMB) (6380 9800) to witness the sealing/grouting work. No demolition or grouting of abandoned sewers/pumping mains/inspection chambers/manholes or other sewerage facilities shall be carried out without PUB’s approval.
Where existing manholes/inspection chambers are to be abandoned, all openings, including those of backdrops/tumbling bays, shall be sealed and made watertight with 225mm thick brickwork rendered with cement mortar.
The top 600mm, or a depth required by the relevant Authority, of the abandoned chambers and manholes shall be removed and the remaining chambers/manholes shall be filled with well compacted approved soil.
The frames and covers of abandoned inspection chambers/manholes are to be removed.
Pipes of all sizes within road reserve and pipes of diameter 300mm and above elsewhere shall be filled/grouted with cement grout or approved materials.
The ends of abandoned drain-lines/public sewers shall be sealed and made watertight with 225mm thick brickwork rendered with cement mortar.
The Developer/QP is required to reflect the actual manner of abandoning the sewers/pipes and manholes/chambers in the as-built drawings, including indicating the locations of all watertight seals and submit the drawing to PUB (BPD).
Precautionary measures are to be taken to prevent cement grout from entering the sewers which would still be in use.
The safety procedures/requirements for working in a confined space are to be complied with.
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