Key Build Stage 1 Drainage
|
Traditional drainage checks |
Evidence |
Frequency |
|---|---|---|
|
Verification of pipe material |
Ticket |
All sources |
|
Verification of precast concrete units |
Ticket |
All sources |
|
Verification of surface water covers & frames |
Ticket |
All sources |
|
Verification of bedding material |
Ticket |
All sources |
|
Verification of backing material |
Ticket |
All sources |
|
Inspection of pipe bedding |
Visual |
All lengths |
|
Inspection of line and level of laid pipes |
Visual |
All lengths |
|
Inspection of backfill (Type 1/Type 3) and compaction |
Visual |
All lengths |
|
Verification of protection method of any pipework. |
Visual |
All lengths |
|
Check dimensions of any highway drain |
Visual |
All lengths |
|
Air tests on pipelines |
Testing |
Each length between chambers |
|
Sustainable drainage checks |
Evidence |
Frequency |
|---|---|---|
|
Verification of type B sub-base material |
Ticket |
All sources |
|
Verification of geotextile |
Ticket |
All sources |
|
Verification of grass seed & turf species |
Ticket |
All sources |
|
Confirm air voids ratio for sub-base -permeable paving |
Ticket |
One sample |
|
Check SuDS dimensions / profile on site |
Visual |
All lengths |
|
Check sub-base depth & width in SuDS filter strip |
Visual |
As required |
|
Check correct erosion & scour protection on outlet pipes |
Visual |
As required |
|
Check top soil depth |
Visual |
All lengths |
|
Confirm check dam locations |
Visual |
As required |
|
Check sub-base depth |
Visual |
All lengths |
|
Laying and lapping of geotextile – ensuring overhang runs up the back of the back of the kerb race |
Visual |
All lengths |
|
Groundwater levels are in accordance with the approved design |
Visual |
As required |