Appendix I — Work-as-Executed Survey
Generally the following information needs to be recorded:
- Pipeline Details
For sewers, the nominal size, material, class, location, length between inside faces of maintenance holes, and the invert levels at the upstream and downstream inside faces of maintenance holes. Similar information is required for water mains.
- Maintenance Holes, Valves and Associated Structures
The location, type, material and size of all maintenance holes, valves, hydrants, pits and associated structures including the invert levels of sewers at the upstream and downstream faces of maintenance holes (also the window sill level on the inlet pipe if the maintenance hole has an external drop), and cover levels.
This information should be provided to the following accuracy:
- +/- 200mm in plan (for water mains and sewers)
- +/- 10mm in level (for sewers less than one per cent grade)
- +/- 20mm in level (for sewers greater than one per cent grade).
Appendix J — Water Supply Inspection Checklist
The following items are usually checked during all Icon Water inspections. This list is only intended as a guide checklist, it is not exhaustive:
- alignment of mains (distance from kerb to all hydrants and stop valves is recorded on marked up drawings);
- cover over the main (check at hydrants, valves and at random other locations if problem is suspected);
- hydrant heads are at the correct depth;
- hydrants and valves are in the correct locations;
- all hydrants and valves have been installed correctly and are clearly marked;
- every property has a service in the correct location and all services have water meters fitted;
- stopcocks are installed at the correct depth and are fitted with a properly sized clean access pipe;
- valve covers, hydrant covers, and pits are installed or constructed properly (for example, are finished at correct height above ground and are properly drained);
- all pits have drainage outlet pipes and headwalls;
- where visible, anchor blocks are of appropriate size and bear on undisturbed ground;
- all flow and/or pressure control devices are properly installed and are able to carry out their intended function once set up during commissioning (e.g. pressure reducing valves installed facing the correct way and fitted with tapped-in pressure gauges);
- any temporary works called for under the contract have been completed in accordance with the drawings;
- damage to any part of the works being inspected (e.g. markers, covers);
- all airvalves and scours have been installed in accordance with the approved drawings.
Appendix K — Sewer Inspection Checklist
The following items are usually checked during all Icon Water inspections. This check list is intended as a guide only, it is not exhaustive.
Confirm that the visible parts of the sewerage system have been constructed to:
- Function in accordance with design intent, by:
- Maintenance hole channels having the correct width and depth, the sidelines into the main channel being curved in accordance with standard drawings;
- Sewers being of the correct size and showing no evidence of ponding.
- Be of acceptable quality, viz.:
- Maintenance hole walls are solid and have smooth, plastered inner walls, where the benching is solid and not drummy;
- Flexible joints have been installed on pipes connecting to maintenance holes;
- Sewer lines are clean and straight (where appropriate);
- Curved sewer lines can be flushed through with a proving ball;
- Trench or scour stops are installed on pipes laid on grades 5 to 15per cent, and scour stops are installed on grades exceeding 15per cent;
- Foundations for maintenance holes constructed on existing sewers are examined before the base is poured;
- No bandage joints (compo joints) are constructed on new sewers;
- All stubs out of maintenance holes are sealed with discs;
- Air tests are carried out on sewers and service ties;
- All broken or damaged sewers are re-tested;
- Pre-cast maintenance holes are identified by a manufacturer's stamp;
- External drops for DN100 house connections use DN150 drop junctions;
- Pre-cast maintenance hole components are primed in the factory ready for jointing;
- No mixture of pre-cast and cast in-situ concrete exists above the base level of maintenance holes;
- Covers not fitting the rebates are replaced.
- Minimise potential hazards to maintenance personnel or public, viz.:
- Cover levels are flush with pavements, 25mm above surface in landscaped areas and 75mm above surface elsewhere. The area surrounding the maintenance hole is filled and graded evenly to the top of the seating ring;
- Heavy duty covers are provided where required (see Icon Water's Water Supply and Sewerage Standards Part 3, Clause 5.1.16);
- Maintenance hole step-irons are solidly fixed, on downstream side, in line and correctly spaced;
- Deep maintenance holes (over 6.0 metres) are DN1200, have ladders in lieu of step-irons and have landings.
- Be readily maintainable, viz.:
- Have clear access to the maintenance hole cover;
- Have a maximum slope of 1 in 10 on maintenance hole covers and provide space to rest the removed cover;
- Have maintenance hole necks between 100mm and 200mm in height.
- Connect neatly to the existing system, viz.:
- No damage has occurred to the existing system in the connection.