Infrastructure Development Code

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The following shall also be considered as part of the design process:

  1. DS-7.9.1 Manholes and Chambers for Control Valves and Bulk Flow Meters.
  2. DS-7.9.2 Special Measures for Pumping and Storage.
  3. DS-7.9.3 Trenchless Pipe Installation.
  4. DS-7.9.4 Rural.
  5. DS-7.9.5 Easements.

DS-7.9.1 Manholes and Chambers for Control Valves and Bulk Flow Meters

Drawing Ref: T722, T741, T742, T743, T744

Chambers are required for control valves (generally pressure reducing valves and bulk water meters) and shall be specifically designed. Designers are encouraged to discuss their design with Council prior to completing the detailed design of a chamber. Designs shall consider the following parameters: 

  1. Fittings
    1. Spacing between valves, fittings, upstream and downstream faces of bulk meters shall be allowed for in accordance with the manufacturers’ recommendations. As a minimum, 5 diameters upstream and 2 diameters downstream of bulk meter flange faces shall be straight pipe lengths.
    2. Sufficient clearance and appropriate fittings shall be allowed for to facilitate installation, access to bolts and dismantling and removal of equipment, including sufficient clearance from the face of the chamber to flanges.
    3. Space for practical access and maintenance between the fittings and the chamber sides/floor shall be allowed for.
    4. Reducers and isolating valves shall be installed outside of the chamber. Anchors for thrust and/or movement prevention shall also be constructed outside the chamber in accordance with T722.
    5. All flush joints shall to be sealed to ensure water tightness. 
  2. Chamber
    1. Chambers housing control valves (with or without bulk meters) shall have a full opening access. 
    2. Chambers housing bulk meters may have a standard cast iron 600mm Ø manhole lid where the chamber will be infrequently accessed. Should the operation of this chamber require frequent access, Council shall be contacted for advice. 
    3. Galvanised mild steel supports shall be designed to provide vertical support for the infrastructure. Please refer to T741.
    4. Access steps shall be per AM-5.4.4.
    5. Where chambers are situated in free draining soils and not at risk of high water tables, drainage of the chamber shall be provided for.
    6. The chamber pipe interfaces shall be sealed to prevent water/moisture ingress. Chamber joints are to be sealed.
    7. Chambers situated where there is risk of surface inflow of water shall have a double sealed cast iron lid installed to prevent water ingress. A localised sump may also be necessary and requires discussion with Council on a case by case basis.
    8.  Refer to Table 7.6: MH/Chamber Sizing for guidance on selecting the appropriate chamber size.

 Table 7.6: MH/Chamber Sizing

Type of Infrastructure Nominal Diameter of Infrastructure Chamber Diameter Lid Diameter
Bulk Meter (BM) < 200mm 1050mm Ø 600mm Ø
Bulk Meter (BM) >200mm 1200mm Ø 600mm Ø
Pressure Reducing Valve (PVR) <200mm 1200mm Ø 1200mm x 1200mm
Pressure Reducing Valve (PVR) >200mm 1500mm Ø 1200mm x 1200mm

Combo

(BM + PRV)

80mm / 80mm 1200mm Ø 1200mm x 1200mm

Combo

(BM + PRV)

100mm / 10mm 1200mm Ø 1200mm x 1200mm

Combo

(BM + PRV)

150mm / 150mm 1500mm Ø 1200mm x 1200mm

Combo

(BM + PRV)

200mm / 200mm 1650mm Ø 1200mm x 1200mm

Combo

(BM + PRV)

>200mm / 200mm Specific Design Specific Design
  1. For further guidance regarding the sizing of chambers, refer to T741.
  2. Operation and maintenance shall be considered including confined space access and mitigation of risk to maintenance personnel.
  3. Bulk meters and control valves that are required to be linked to telemetry, shall include ducting and support for cables entering (and being fastened to) the chamber without compromising the chambers requirement to be watertight or the ability to access it.

DS-7.9.2 Special Measures for Pumping and Storage

Approval is required from Council before undertaking detailed design. Detailed design shall be required at the time of Development Works Approval. Where no Development Works Approval is required, then Council approval shall be obtained at a time required by Council before construction of the system.

DS-7.9.3 Trenchless Technology

The following shall apply:

  1. Trenchless technology may be preferred or required for alignments passing through or under:
    1. Environmentally sensitive areas.
    2. Built-up or congested areas to minimise disruption and reinstatement.
    3. Railway and major road crossings.
    4. Significant vegetation.
    5. Vehicle crossings.
  2. DS-7.5.3 Water Main Pipe Requirements specifies the minimum pipe classifications for trenchless installations however, designers shall still satisfy the following:
    1. The pipe material chosen shall have a tensile strength that exceeds the expected pull force. This could vary with ground conditions, contours, bends etc.
    2. Other factors such as the depth of pipe installation and expected load or trafficking over the pipe shall be factors of the design
    3. Trenchless installation does not provide the same quality of compaction as open cut installation therefore the ground support on the pipe wall can be less than compacted open cut installations. This shall be considered when confirming the pipe classification.
    4. The design pipe classification shall be confirmed within the design documentation and meet the requirements of AS/NZS 2566 Part 1.
Explanatory Note:
Council has set a minimum of “one pipe class up” for trenchless installation compared to open cut installations. This is the starting point for trenchless pipe selection but may still be inappropriate due to ground conditions that affect compaction strength, reduced ground support for the pipe, the “pull” strength required and / or scraping and scratching of the external wall of the pipe. 
  1. Designs shall confirm the position of all underground utilities and obstructions. No damage to other utilities, structures or similar shall be permitted.  

Refer to CS-13 Trenchless Technology for information on trenchless technology installation.

DS-7.9.4 Rural

The following shall apply:

  1. Where Council has not provided supply to meet either fire fighting or residential supply needs, a suitable supply of potable water shall be provided.
  2. Storage shall also be provided to meet the fire fighting capacity requirements for the relative activity as per PAS4509. For a residential dwelling this means a minimum on site storage requirement of a minimum of 40,000 litres storage, installation of a toby connection and all weather access.
  3. Where principal or trunk watermains are laid "across country" or not parallel to boundary lines, the location of the watermain is to be marked by H4 treated timber or concrete valve/hydrant posts, painted white, without the H or V mark.
Explanatory Note:
Council is not required to provide potable water to meet residential supply or fire fighting requirements outside of the urban water supply catchment. In these locations, should reticulation be available, connection may be made but no guarantee is provided about the adequacy of supply.

DS-7.9.5 Easements

Please refer to:

  1. DS-1.22 Easements.
  2. DS-1.22.9 Easements: Water Supply.

Definitions in this section

Council

Design

Designer

Development works approval