Technical requirements for water supply

 

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  • 1 General design considerations

    1.1 Objectives

    The key objective of Icon Water's water supply system is to provide safe, potable, adequate, reliable, efficient and effective water supply facilities for the urban areas in the ACT. This service is to be provided in an economically and environmentally sustainable manner.

    Specific aims are:

    1. providing headworks (dams, transmission and treatment facilities) with sufficient capacity to supply total assessed demand and environmental flows through periods of drought, equivalent to the worst on record (on the basis of records since 1912);
    2. providing adequate distribution facilities (bulk supply mains, pump stations, service reservoirs, distribution and reticulation systems) which meet assessed peak hour demands, and exhibit a low probability of water shortages during prolonged periods of high demand. Reliability criteria also requires maintenance of at least a limited supply under breakdown conditions. The exception being within small local areas isolated to effect repairs;
    3. providing a level of fire fighting capability from Icon Water's mains adequate in relation to the current ACT Fire Brigade recommendations as set out in this document;
    4. maintaining a safe, potable, adequate and reliable water supply to all consumers.

    This part of Icon Water's Water Supply and Sewerage Standards (Part 2) covers the design of water supply distribution and reticulation systems downstream of service reservoirs. It provides a brief general background on design aspects but does not cover the planning and design of dams, treatment plants, pump stations, service reservoirs or bulk supply mains. The design of these latter elements requires a detailed knowledge of the system, and a specialised and specific design approach based on the state of technical knowledge at the time the particular facility is required. Such design would normally be based on a Water Supply functional brief.

    The reticulation design must be compatible with the overall strategy plan. When designing for final delivery to customers, the actual reticulation layout shall be designed for, and take into account water quality, pressure, flowrate, and staging and supply security, so that Icon Water's ability to comply with regulatory and customer agreements is not compromised. Hydraulic calculations performed by the designer shall be submitted to Icon Water in support of the design.

    1.2 Maintenance aspects

    1.2.1 General

    Icon Water's Water Supply System is to be designed with due regard to the continuing maintenance requirements after the works have been constructed. A system that can be easily and economically maintained is essential.

    1.2.2 Special Equipment

    The purchase of special maintenance equipment and plant requires considerable lead times, special approvals and funding. As a consequence, no design incorporating the need for special or unusual equipment should be prepared without the prior written approval of Icon Water.

    This requirement also extends to the need to use special techniques or hired equipment. To ensure that maintenance personnel can respond and overcome operational problems consistent with service objectives, it is essential that maintenance of the system is not dependent on non-standard techniques or equipment.

  • 2 Location of water mains

    2.1 Environmental and heritage considerations

    The environmental impact of the project shall consider the relevant Environmental Protection Acts listed in Part 1, General Design Standards (Clause 5).

    2.2 Alignment

    Standard alignments for water supply mains in the nature strip are shown on Road Verge Drawings - Drawing Nos. SEP4 - 01 to 06, Chapter 4 (Road Verges) (Reference 10.5). Special alignments may be used where necessary, however, these are always subject to the provision that the alignment is not already reserved for another service. Easements across privately leased land should be avoided.

    2.3 Pipe deflection

    Deviation of a pipeline around an obstruction can be achieved by deflection at pipe joints or in combination with bends or connectors. The deflection angle permitted at a flexible joint shall be in accordance with the manufacturer's recommendation. For laying PVC or PE pipes on curves, minimum radii are to be as per manufacturer's recommendations. If deflection of joints does not provide the necessary deviation, bends and other fittings shall be employed.

    2.4 Landscape requirements

    A requirement of the design process is to produce a landscape survey of the proposed area of construction to assess the effect of the project on shrubs and trees. Trees to be retained should be identified, marked and methods of protection determined. Vegetation such as mature trees and other natural habitat for fauna shall not be removed unnecessarily.

    Backfilling of trenches shall be arranged to provide topsoil at the surface of the trench, and shall be such that no depressions are left along pipe alignments after settlement of the soil. Special care is required in restoration of highly visible sites and existing pavements.

    2.5 Pipelines in easements

    Water mains that are located anywhere other than in the road reserve of a dedicated public road shall be located within an appropriately sized water supply easement subject to Icon Water's approval. For general information on easements refer to Part 1, General Design Standards (Clause 3.2).

    2.6 Locating buried mains

    Tracer wire shall be used for all non-metallic water mains for the purpose of locating buried mains (by passing a signal through the wire, which can then be picked up by the detector). PVC coated copper wire (1mm) shall be taped to the non-metallic main in a continuous length. For further details refer to Clause 6.7 and Standard Drawing No. WSS 020. At every hydrant, sufficient slack shall be left to enable the wire to be brought up to the surface within each hydrant surround, wound three times around, and taped to the hydrant immediately below the hydrant head.

    Marking tape to AS 2648 shall be laid in a continuous length on top of the pipe embedment material, 150mm above all water mains. For details of underground marking tape requirements refer to Standard Drawing No. WSS 020.

    2.7 Provision of branches for future connection

    Many branches provided for future development turn out to be either the wrong size, in the wrong place, or not eventually required. Temporary end caps on such branches are often not satisfactorily anchored, and become a liability if the branch is not subsequently used. To avoid this, the following is required:

    • branches for future development shall not be provided unless the alignment and diameter of the future connecting mains are confidently known, and the extension is to occur within a short time span (less than 12 months);
    • to avoid anchorage problems and future shut downs of the main, a flanged branch with a stop valve is preferred to a branch with an end cap. Valves shall be blank flanged. Where an end cap is necessary a full and adequate thrust block shall be provided;
    • where a branch is proposed to be laid across a road, the section across the road should be end capped at both ends rather than connected at one end initially (to avoid future road openings). If the pipes are not to be connected within 24 months, consideration should be given to charging it via a DN20 service connection and then flushing periodically.
  • 3 Hydraulic design

    Network analyses of the water reticulation system under development shall be undertaken by the designer to ensure that an adequate and safe water supply is available to all consumers connected to the system for all defined modes of operation. The system under development shall be in accordance with the hydraulic design parameters mentioned below.

    3.1 Water supply master plan

    The design of the water reticulation network including pipe layout and sizes, fire risk categories, zone boundaries, and valving to meet breakdown requirements shall be shown on a Water Supply Master Plan, details of which are included in the Asset Creation Approval Processes (Appendix C). The design criteria used in preparing Water Supply Master Plans are briefly explained in the following clauses.

    3.2 Peak hour demand

    The peak hour demand for Icon Water's overall system generally occurs on summer evenings, when residential sprinkler use is high. This evening peak hour demand depends on the 'per-hectare' maximum hourly rate for various land use types and the percentage of this rate used during the evening peak hour. Maximum hourly rates are regularly reviewed, with the current rates and their relative evening peak hour percentages shown in Table 2-1.

    3.3 Fire demands

    Pipe sizes on master plans are designed to allow for fire fighting flows recommended by the ACT Fire Brigade, and are shown in Table 2-2, at one frontage concurrently with peak hour demands (but not breakdown).

    Pipework in areas designated 'medium density', with no other description, are sized for fire risk TYPE F6. For cases where doubt exists as to the fire risk type, reference should be made to the ACT Fire Brigade.

    Hydrant types and layouts specified in Table 2-3 are provided as recommended by the ACT Fire Brigade to ensure that the required fire flow is available from hydrants, within 150 metres of the fireground, during peak hour demands. Residual pressures in Icon Water's mains are specified in Clause 3.5.3. For areas of fire risk types F1, F2 and F3, hydrant type and layout should be ascertained from Icon Water. This will permit advantages to be taken in those areas where an Icon Water main residual pressure is higher than the minimum 10 metres head, resulting in rationalisation and savings. Supplementary hydrants may be required for private fire services on some projects.

    Where fire fighting flows higher than those tabulated are required within private firefighting systems, or where a guaranteed flow is required even under breakdown conditions, additional private storage tanks and/or booster pumping may be required. In certain circumstances direct boosting from Icon Water's mains may be permitted, however, details of any such proposal must be submitted for checking and approval by Icon Water to ensure that there is no adverse effect on the adjacent public system.

    Under the provisions of the Fire Sprinkler Code (AS 2118), distribution layouts are not specifically arranged to provide two independent full capacity feeds to blocks requiring a fire sprinkler supply with high reliability. However, this level of protection is often either available, or can be provided at a moderate extra cost to the leaseholder through minor changes to the system layout.

    Distribution layouts and fire flow risks assume that fire sprinkler demands and internal fire hydrant demands are included in the fire flows listed in Table 2-2. Hence, if these demands are concurrent, the fire flows available from Icon Water's main system are reduced accordingly.

    Table 2-1
    Maximum hourly rates and evening peak hour percentages


    Land use Maximum hourly rate (L/S/net hectare) Evening peak hour percentage (of max hourly rate) Comments

    Standard detached housing

    1.5

    100

    Based on block area

    Group housing and duplex

    1.5

    100

    Based on block area

    Low rise flats

    1.5

    100

    Based on block area

    High rise flats

    1.5

    100

    Based on floor area

    Suburban hotels or clubs

    1.5

    100

    Based on site area

    Neighbourhood and District centres

    1.1

    75

    Based on site area

    Town or City centres

    1.8

    60

    Based on site area

    Office buildings less than three-storey

    1.0

    60

    Based on site area including parking

    Office buildings threestorey or more

    1.8

    60

    Based on floor area

    Sports centres

    1.5

    100

    Based on site area

    Schools

    l.9

    60

    Based on site area

    Hospitals, Nursing Homes

    1.7

    100

    Based on site area

    Other Institutional

    0.9

    50

    Based on site area

    Light Industrial

    0.9

    60

    Based on site area

    Playing fields: automatic night watering

    3.5

    43

    Based on irrigated area. Figures assume 38 mm/wk over 30 hours

    Future development, details unknown

    1.5
    or
    1.05

    100

    100

    Based on block area

    Based on gross area which includes local streets, walkways, but excludes arterial roads, floodways and all other non-consuming areas



    Table 2-2
    Fire risk types and flows as recommended by the ACT Fire Brigade


    Fire Risk Development Minimum Water Requirement
    TYPE F1 Town Centres, Major Shopping Areas 200 L/s
    TYPE F2 Major Industry, Major Hospitals, Major Office Development 150 L/s
    TYPE F3 Large Offices, Large Educational Establishments, Very Large Shopping Areas 100 L/s
    TYPE F4 Light Industry, Large Institutions, Large Places of Public Assembly, Large Shopping Centres, Schools, Colleges (unless classified F3), Group Centres, Higher Risk Residential Areas individually classified F4 60 L/s
    TYPE F5 Minor Shopping Areas, Small Institutions, Small Places of Public Assembly, Medium Density Housing, Duplex, Flats and Dwelling Units more than one selfcontained unit high unless individually classified F4 45 L/s
    TYPE F6 Detached Housing, Medium Density Housing, Duplex, Flats and Dwelling Units not more than one self-contained unit high 25 L/s


    Table 2-3
    Fire risk types and hydrant layouts as recommended by the ACT Fire Brigade


    Fire risk classification (refer Clause 3.3) Fire fighting water requirement Hydrant provision
    TYPE F1
    TYPE F2
    TYPE F3
    200 L/s
    150 L/s
    100 L/s
    One high capacity hydrant as close as possible to the end of each cul-de-sac and at 135m intervals along the main interspersed with standard hydrants at 45m intervals (see Clause 3.3).
    TYPE F4 60 L/s Three standard hydrants together as close as possible to the end of each cul-de-sac and single standard hydrants at 60m intervals along mains.
    TYPE F5 45 L/s Two standard hydrants together as close as possible to the end of each cul-de-sac and single standard hydrants at 60m intervals along mains.
    TYPE F6 25 L/s One standard hydrant as close as possible to the end of each cul-de-sac on DN100 or larger mains and at 90m intervals along mains. For reticulation mains smaller than DN100 (Clause 3.9, Standard Drawing No. WSS 026), one standard fire hydrant on the DN100 main just prior to tapering down to DN63 PE pipe and one standard hydrant at the end of the DN63 PE pipe for mains flushing purposes. If there are no other fire hydrants within 150m of the end of the cul-de-sac, then two hydrants together shall be provided just prior to tapering down.
    UNTYPED Unspecified One standard hydrant at 180m intervals along roads in which a main is located and where no fire risk other than vehicle fires is apparent. A hydrant connected by a hydrant bend shall be provided at the end of mains.

    3.4 System reliability

    All elements of Icon Water's water supply system should be planned and detailed to ensure as high a level of reliability as is reasonable. Features incorporated into a system layout to enhance reliability include the following:

    • for critical mechanical equipment, a standby capacity sufficient enough to maintain full capacity with any one element out of service;
    • for distribution systems downstream of reservoirs, a 'looped' rather than 'branched' layout is generally used to provide more than one supply route on distribution systems. Valving is arranged as described in Clause 5.4. These valving arrangements help to limit the area needing to be shut down when isolating and repairing any section of main;
    • for all reservoirs, either duplicate tanks or pressure regulated bypass arrangements to maintain a rate of supply to the distribution system equivalent to at least the design bulk supply rate (if the reservoir is out of service);
    • emergency storage in reservoirs, which in addition to providing a reserve for fire fighting, can be used to maintain a distribution supply for limited periods during bulk supply interruptions. Inter-zone connections or other arrangements can usually be made to maintain some supply. In some extreme cases, it may be necessary to contact consumers and request sparing the use of water until repairs can be completed. The limited periods referred to above, for maintaining supply, range from a few hours during prolonged high demand (in summer) to a few days during low demands in winter.

    3.5 Pressure requirements

    3.5.1 Maximum pressures

    Pressure zoning is arranged wherever possible to limit the maximum static pressure at any point to 75 metres head. In special cases this is relaxed to 90 metres head.

    There are two areas within the ACT where maximum static heads over 100 metres currently exist:

    • the Woden town centre area below contour 587 metres AHD could experience a maximum static head in excess of 100 metres up to 107 metres;
    • the North Canberra area, which comprises the City, Acton, Braddon, Turner, Reid, Lyneham, Dickson and Downer below contour 575 metres AHD, could experience a maximum static head in excess of 100 metres and up to 115 metres.

    All pipework shall be designed for the field test pressure as defined in Clause 3.5.4, for the following reasons:

    1. to allow for the use of inter-zone connections during emergencies;
    2. to allow for waterhammer;
    3. to allow for standardisation of equipment and flexibility of use.

    3.5.2 Minimum pressures under peak hour demands

    Pipework is sized to ensure, during peak hour demands, that the minimum residual pressures at Icon Water's mains are as follows:

    • for domestic development not exceeding two storeys in height: the equivalent of 20 metres head over the highest point on the block.
    • for domestic development exceeding two stories and for shopping, commercial and industrial: the equivalent of 30 metres head over the highest point on the block.

    For very large blocks such as institutional campuses, an extra allowance of 5 metres head for every 1000 metres distance, between the main and the most critical point on the block (with regard to either elevation or distance from the main), is permitted.

    Stated residuals are to be achieved with service reservoirs at half capacity and an allowance for reservoir outlet losses of 1.5 metres. The system should be checked to ensure that the same residuals can be achieved at 50% peak hour demands with any one element out of service.

    3.5.3 Minimum pressures during firefighting

    Pipe sizes should be checked to ensure that, while drawing the specified fire fighting flow at points within 150 metres of the fireground (concurrently with peak hour demands), residual pressures at Icon Water's mains do not fall below the equivalent of 10 metres head. This residual is to be achieved with reservoirs at half capacity and an allowance for reservoir outlet losses of 1.5 metres. No performance criteria are set down for combined fire flows and breakdowns.

    3.5.4 Field test pressures

    Pipework shall be designed for a hydrostatic field test pressure as follows:

    • for reticulation pipework, unless a higher test pressure is specified on Water Supply Master Plans, the equivalent of 140 metres head of water at the lowest point within the developed area of the zone;
    • for other pipework, a test pressure as specified by Icon Water, but not less than the equivalent of 140 metres head of water at the lowest point of the newly constructed works.

    It should be noted that a pressure test is intended to detect leakage at operating pressures which may actually be experienced during the life of the pipework, and not as a test of ultimate pressure capacity. In the design of thrust blocks suitable safety factors shall be incorporated.

    3.6 Headloss

    As a guide for economic designs, pressure zoning of the reticulation systems should be based on a headloss of 5m/km radially from the reservoir. This often approximates to maximum headlosses of 3m/km along distribution mains.

    3.7 Pipe roughness

    Reticulation mains are to be sized to provide the minimum heads (specified above) using the Colebrook-White equation. A pipe roughness value (k) of 0.3mm averaged over the life of the main is to be used when no allowance is made for valves and fittings. A pipe roughness value (k) of 0.15mm should be used if specific allowances have been made for valves and fittings.

    3.8 Design velocity

    Ideally, the velocity in water mains should range between 0.5m/s and 2.0m/s. However, under extreme conditions (e.g. fire flows in high fire risk areas) velocities up to 5m/s are acceptable. Very low velocities in pipes cause water quality problems due to long detention times and should be avoided if possible. Minimum diameters and lengths of main should be constructed consistent with meeting the required demands on the network. Generally, dead end mains with tapered diameters below DN100 should be used in cul-de-sacs.

    3.9 Minimum sizes of mains

    Sizes shall be determined by network analysis, with special attention to be given to the specification of fire flow capacity.

    The minimum size of reticulation mains shall be DN100 for fire risk classification F6, namely residential development, and DN150 for fire risk classifications F1 to F5, namely industrial, commercial, medium density, and residential etc. (Table 2-2). Reticulation mains smaller than DN100 may be used in locations (e.g. small cul-de-sacs - Standard Drawing No. WSS 026) where only consumer connections are required. These locations could otherwise experience reduced water quality due to long detention times or sediment build-up.

    3.10 Length of DN100 mains

    Head losses in small mains, under fire demand conditions, are such that long lengths are unsatisfactory. In residential areas mains should be laid out to restrict lengths of DN100 main, especially on single ended feeds.

  • 4 Structural design

    4.1 General detailing requirements for pipelines

    As mentioned in the introduction, there is a demonstrated need to construct systems in a standard configuration using tried and proven methods and materials. Within the ACT, any deviation from normal practice has the propensity to increase stock holdings for spare parts, and create additional maintenance costs by way of labour charges. Any deviation from standard practice will require the specific approval of Icon Water. A submission detailing the proposals, in full, must be made to include an economic and long term benefit analysis, and the covering life cycle costs. The costs of burst mains can quickly erode cost differentials of the initial costs in pipe networks. Unless otherwise noted, the current version of Australian Standards shall apply.

    4.2 Pipe materials and diameters

    Unless specifically approved otherwise by Icon Water, pipes for water supply shall be selected from the following approved materials:

    • ductile iron, cement lined and rubber ring jointed, produced in standard lengths of 5.5 metres to AS 2280, having sizes of DN100, 150, 225, 300, 375, 450, 500, 600 and 750. For pipes up to DN300 an approved seal coating on the internal cement mortar lining is applied to reduce leaching; above DN300 the need for a coating will be determined by Icon Water. Class K9 shall be used for general application including direct tapping, and class K12 where additional structural capability is required;
    • PVC Class 16 to AS/NZS 1477 Series 2, having sizes of DN100, 150, 225, 300 and 375. Direct tapping is not permitted;
    • modified PVC (PVC-M) Class 16 to AS/NZS 4765 (Int) Series 2, having sizes DN100, 150, 225, 300, 375 and 450. Direct tapping is not permitted;
    • molecular Oriented PVC (PVC-O) Class 16 to AS/NZS 4441 (Int) Series 2, having sizes DN100, 150, 225, 300 and 375. Direct tapping is not permitted;
    • for sizes above DN750, steel pipe to AS 1579, cement mortar lined to AS 1281, and externally coated with fusion bonded polyethylene;
    • PE, pressure class PN16, to AS/NZS 4130 having size DN63. Direct tapping not permitted.

    If a change in pipe material is to occur within the area covered by a particular project submission the extent of the different materials used must be clearly delineated on the design submission drawings.

    Use of other pipe materials may be approved in special cases.

    Metal pipes and spigots of metal fittings shall not be inserted into PVC or PE sockets. Metal fittings to be connected to PVC or PE pipes are to be socketed fittings only.

    4.3 Corrosion protection of pipes

    1. Internal lining: All ductile iron and steel pipes, fittings and specials shall be cement mortar lined (factory installed) or epoxy lined unless special conditions (i.e. excessive velocity) or factors (i.e. weight considerations) exist which prohibit a lining of this type. In these special cases ductile iron and steel pipes, fittings, valves and specials are generally lined with a high build solventless epoxy paint system approved for use in potable water supplies;
    2. Polyethyl ene wrapping: In addition to the factory applied coating, all ductile iron pipes and fittings of size DN225 and larger shall be protected upon pipelaying with an overwrapping of green polyethylene sleeving or sheet. Details of this overwrap shall be to the requirements of AS 3680. Special attention shall be paid to wrapping details at house connections where the ductile iron pipe manufacturers recommendations should be followed;
    3. Welded or flanged joint protection: Welded joints in buried steel pipelines shall be externally protected with a joint protection system acceptable to Icon Water. Buried flanged joints in steel or ductile iron pipelines (prior to polyethylene overwrap) shall be similarly protected;
    4. Cathodic protection: Buried steel pipelines, whether flanged or welded, may require induced current or sacrificial anode type cathodic protection. Reference should be made to Icon Water for guidance.

    4.4 Cover over pipelines

    The minimum cover to water mains shall normally be 750mm in roadways or traffic areas and 600mm elsewhere. The minimum cover to water services shall be 450mm in roadways or traffic areas and 375mm elsewhere. Provision shall be made for transient loads such as construction equipment where cover is reduced during the construction phase.

    Repairs on pipelines laid at excessive depths are difficult and costly, and often result in the pipeline being out of service for an unacceptably long period. All reasonable steps shall be taken to avoid exceeding a trench depth of 1.5 metres. Concurrence of Icon Water must be obtained where works propose a greater trench depth than this. The maximum depth of a service pipe shall be 1.5 metres.

    Refer also to Standard Drawing No. WSS 012 for details on cover over pipelines.

    4.5 Insufficient cover over pipelines

    A pipeline shall be lowered when cover is removed from existing pipelines for new works (such as roads). If this is physically impossible then consideration shall be given to protection by a suitably designed reinforced concrete relieving slab; extending at least 500mm into natural ground beyond existing pipe trench lines. This slab shall be segmented by construction joints into maximum l.0 metre long easily removed segments, and separated from the pipe obvert by no less than 25mm of granular or compressible material. Notwithstanding, specific concurrence of Icon Water must be obtained.

    4.6 Thrust blocks

    Thrust or anchor blocks of plain or reinforced concrete, which have been designed to resist unbalanced hydraulic forces, shall be provided at all bends, tees, tapers, in-line stop valves and dead ends. Wherever applicable, thrust blocks shall be sized in accordance with Standard Drawing Nos. WSS 013 and WSS 014.

    Appropriate geotechnical advice should be sought by designers to determine allowable bearing pressures to be used. Thrust or anchor blocks not covered on Standard Drawing Nos. WSS 013 and WSS 014 shall be designed for the appropriate allowable bearing pressure in either mass or reinforced concrete.

    Restrained joints (Tyton-Lok or approved equivalent), as an alternative to concrete thrust or anchor blocks, can be considered for use with ductile iron pipes and fittings, DN100 to DN300, in accordance with Standard Drawing No. WSS 025. However as there is currently no approved repair fitting for these mains specific Icon Water approval will be required in each instance.

    4.7 Trench and scour stops

    To limit the scouring effect arising from water flow within the pipe bedding material, and also to anchor the pipe, special bedding, trench stops and scour stops may be required in accordance with Standard Drawing No. WSS 012. Scour stops shall be provided along inclined mains where the slope is 5 to 30%. Trench stops can be regarded as an alternative to scour stops and may be provided along inclined mains where the slope is 5 to 15%. To enable easy location, trench and scour stops shall be placed at intervals of equal length with spacing not exceeding that which is specified on Standard Drawing No. WSS 012.

    4.8 Flanges

    Flanges shall conform to AS 4087. Unless otherwise noted, the flange table should be Figure B5 (which is Table C compatible).

    4.9 Alternative pipelaying methods

    Icon Water may at times approve the use of alternative pipelaying technology such as thrust boring, directional boring, or pipe bursting. Where such methods are envisaged to be used Icon Water should be consulted for appropriate standards and specifications.

  • 5 Structures and fittings

    5.1 Sectioning valves

    Sectioning valves are required to isolate mains, thus enabling the system to be shut down or sectioned off for connections, repair, maintenance, dewatering, zoning or when acting as scour valves. Sectioning (stop or sluice) valves will normally be resilient seated or metal wedge gate type. Resilient seated valves shall not be used in situations where frequent operation against high unbalanced heads, high velocities or cavitation are experienced (such as in a scour or bypass). To close a valve, the spindle will turn anticlockwise, as viewed, when facing the spindle cap. These valves shall conform to AS 2638 Class 14, flanged at both ends, with coatings in accordance with AS/NZS 4158.

    5.2 Valve size

    The nominal size of a valve may be reduced below the nominal size of a pipe line providing the reduction in size does not significantly reduce the hydraulic capacity of the main. Such intentions must be identified at the Design Submission stage of the works.

    5.3 Butterfly valves

    The use of butterfly type isolating valves may be permitted for sizes DN500 and greater, provided that:

    • the valves are located in a properly constructed chamber allowing manual access;
    • the chamber is permanently connected to the stormwater drainage system or drained to the natural surface;
    • the valve is fitted with a handwheel and a position indicator that can be viewed from street level.

    Such intentions must be identified at the Design Submission stage of the works.

    The use of butterfly valves in place of gate valves may be particularly useful for larger diameter mains, where excavation to achieve the required cover over gate valves is difficult.

    5.4 Valving layout

    Valve layouts shall be arranged so that the area which must be shut down to repair any section of main is limited. It is deemed that not more than 5 locations of valves will require visiting when isolating any section of pipework. A location is defined as a valve complex, which contains one or more valves within a circle of 10 metre radius. Valves are also required to be installed so that the maximum number of houses in any closure is:

    • 40 Houses for DN100 and DN150 mains;
    • 50 Houses for DN225 mains;
    • 100 Houses for mains larger than DN225.

    Stop valves are required on all branches that branch from a main of larger size and are normally installed next to the flange on the branch tee. The only exception is for DN100 branches off DN150 mains where stop valves are not mandatory. Stop valves shall never be located under road pavements, and shall be clear of sumps, maintenance holes, driveways, etc. Except where impractical, valves on branches shall be bolted to a flanged branch.

    Where a main is located within an easement on privately leased land, repairs to a burst main may take longer than usual (due to access problems). For mains within easements, a stop valve shall be provided at each end of the easement, outside the property boundary, with no service connections between the two valves.

    5.5 Valve boxes for buried valves

    All sluice valves larger than DN450 shall be installed in a valve box to allow maintenance to be undertaken. Construction of the valve box chamber should be in accordance with Standard Drawing No. WSS 019.

    5.6 Pressure zone boundary valves

    Pressure zone boundary valves shall be installed in a paired configuration with a standard fire hydrant located between them. Installation in this manner permits the valves to be checked for leakage, and permits flushing of the dead end without interference to consumers. The valve on the low pressure zone side will normally be closed in order for the fire hydrant to be used for firefighting purposes (with the supply coming from the high pressure zone).

    5.7 Reflux valves

    When reflux valves are installed in the reticulation, they are to be installed in conjunction with a sluice valve and fire hydrant as shown on Standard Drawing No. WSS 022. This facility is to allow for easy checking of the reflux valve action.

    5.8 Pressure reducing valves (PRVs)

    When PRVs are installed in the reticulation they shall be installed in conjunction with a downstream isolating valve which is to be located before any services that may be connected to the downstream pipework. The PRV must be fitted with pressure gauges both upstream and downstream of the valve and a standard hydrant shall be placed between the PRV and the downstream isolating valve. These facilities are required to allow for the correct setting of the PRVs.

    5.9 Fire hydrants

    Spring hydrants are installed on a DN80 flanged branch directly from the main. The hydrants shall conform to AS 3952, with coatings in accordance with AS/NZS 4158.

    Large capacity fire hydrants are installed on a DN150 flanged branch connection from the main. The minimum size of main being DN150. These hydrants are above ground hydrants and require siting approval from the ACT Planning Authority and the ACT Fire Brigade. The hydrants can be purchased from Icon Water.

    Fire risk classifications for individual areas are to be as shown on Water Supply Master Plans. Hydrant layouts shall be as shown in Table 2-3.

    Each dead ended main shall terminate in a hydrant bend fitted with a standard spring hydrant. See Standard Drawing Nos. WSS 016 and WSS 026.

    Hydrants shall be located in accordance with AS 2419.1. In addition hydrants shall never be located under road pavements, and shall be clear of sumps, maintenance holes, driveways, etc. For hydrant markers on roads see Standard Drawing No. WSS 027.

    5.10 Air release from mains

    Provision shall be made concerning air release from all high points on water mains. This should normally be achieved in reticulation mains by means of a fire hydrant, a branch, or a service pipe located at the high point. Where this cannot be achieved a DN25 single orifice air valve should be provided.

    On bulk supply mains that have no hydrants, air release shall be achieved through the use of DN80 automatic double orifice air valves. Each air valve assembly shall be installed within a chamber designed to prevent backflow of water into the main, and shall be provided with a separate rising stem gate valve (to isolate the air valve from the main). Refer to Standard Drawing No. WSS 015 for details of air valve assemblies.

    5.11 Scour outlets

    On water mains without hydrants (e.g. generally bulk supply mains), scour (or drain) outlets, with isolating valve control, shall be provided at all low points. Wherever possible, on water mains with hydrants (e.g. reticulation), a hydrant should be located at or near all low points.

    Scour outlets should also be provided on bulk supply mains to assist in the draining of each section of main between sectioning valves.

    For larger mains, the size of the scour should be determined after considering (1) the length of time available for draining the pipe section, and (2) the facilities available to dispose of the flow.

    Refer to Standard Drawing No. WSS 021 for details of Type l and Type 2 scour outlets.

  • 6 Service connections

    All connections and cut-ins of new work to existing mains will be carried out by Icon Water after satisfactory testing, inspection and approval of the new work. Refer to the Asset Creation Approval Processes (Appendix H) for procedures, and to Standard Drawing No. WSS 011 for typical details of connections. End caps and anchors on new work must be left in place after testing. Icon Water will remove these at the time of connection. This procedure reduces the possibility of contamination and flooding of the main.

    6.1 Water supply services

    For new leases and in the redevelopment of existing leases water supply services shall be installed by developers of municipal works. The service shall terminate just inside the front property boundary.

    Water supply services shall be installed as per Standard Drawing Nos. WSS 020 and WSS 028. For domestic services the Developer is responsible for installing the service up to and including the meter cock right angle isolation valve in accordance with Standard Drawing No. WSS 020.

    Each lease, irrespective of size, is entitled to one DN20 or equivalent water service. Where requirements exist for a larger service, these must be clearly shown on development proposals and will be subject to specific approval by Icon Water.

    The extension of water services from just inside the block boundary to inside the lease is subject to inspection and regulation under the Water and Sewerage Regulations 2001 (Reference 10.1).

    6.2 Water meter and connection policy

    The number of water supply connections to a lease shall be:

    • one connection to a single residence or single unit non-residential development;
    • two connections to a residential dual occupancy or two unit residential body corporate, with the meters co-located;
    • one connection to each unit in a multi-unit residential or multi-unit non-residential development where all units have an accessible public street frontage; and
    • one connection only to a multi-unit residential or multi-unit non-residential development where one or more of the units does not have an accessible public street frontage;

    A separate un-metered fire service may be required where metering requirements for a combined domestic and fire service are incompatible or are likely to cause water quality problems.

    When a new water connection is required to replace existing services, the existing services must be disconnected at the developer's cost before the new water connection is provided.

    The number of meters serving a lease shall be:

    • one meter on each connection immediately downstream of Icon Water's isolation valve at the block boundary;
    • one meter for each unit in a multi-unit development (both residential and non-residential);
    • a separate meter for common property water usage.

    Although these requirements are not retrospective, it is Icon Water's policy to permit existing developments to adopt these standards where ever possible, but at Icon Water's discretion.

    The connection protocols for different circumstances are described in Icon Water's Water and Sewerage Service and Installation Rules.

    Developments that are required to install multi-unit metering will have a condition placed on the planning approval.

    The hydraulic designer must ensure that the design of the internal hydraulic systems provides protection against noise, shock wave transfer and cross contamination between the dwellings.

    6.3 Water meter issue and sizing

    Icon Water will determine the size of water meters during design approval. The water meters, including associated couplings and meter boxes (small meter sizes only) will be issued to the customers accredited plumber to be installed within fourteen (14) days.

    6.4 Private fire services

    No above ground Millcock Hydrants will be allowed on fire service mains external to buildings. Hydrants in these locations must be underground spring hydrants.

    A combined fire and domestic service main will be allowed:

    • if the meter for the combined services is only one size greater than that of the domestic service main; or
    • where a detector-check valve type meter sized and approved by Icon Water is fitted; or
    • where an alternative arrangement is approved by Icon Water.

    If this is not the case then separate services will be necessary. Icon Water may require a meter or a detector-check valve type meter on dedicated fire services.

    Small diameter fire hose reels must be served from the metered domestic water supply unless they are at first floor level or above, in which case they can be supplied from the fire service water supply.

    The exceptions to this arrangement are multistorey car parks where all small diameter fire hose reels must be served from a metered supply.

    6.5 Service diameter

    Each lease is normally provided with a minimum DN20 copper or DN25 PE water service. To achieve an economical pipe layout mains may not always be located within easy reach of certain blocks. For these blocks, supply through a DN20 copper or DN25 PE service would be comparatively restricted. To compensate, the service size is increased to DN25 copper or DN32 PE in the following cases:

    • where the main-to-property boundary distance exceeds 16 metres;

    Main tapping, copper riser, right angle valve and meter remain at DN20.

    Larger services for future connection are provided only in the exceptional circumstances described in Clause 2.7.

    6.6 Service materials

    Approved materials for the construction of the main-to-copper riser section of the service shall generally be:

    • brass/gunmetal valves with PE pipe PN16, to AS/NZS 4130 as per Clause 4.2;
    • service Size DN20 to DN80 - Brass/gunmetal valves with copper tube to AS 1432 Class B;
    • service Size DN100 or greater - Cast iron isolating valve on a flanged branch tee with ductile iron pipework to AS 2280 as per Clause 4.2 OR PVC, PVC-M or PVC-O pipe Class 16 as per Clause 4.2.

    All services to be provided with an isolating valve. Stop cocks are not permitted on services greater than DN50.

    Metal pipes and spigots of metal fittings shall not be inserted into PVC or PE sockets. Metal fittings to be connected to PVC or PE pipes are to be socketed fittings only.

    To assist in later detection, all water services shall be located at right angles to the main. Tracer wire (PVC coated 1mm copper wire) shall be taped to the non-metallic water service. One end of the tracer wire shall be wound three times around the copper riser and attached just below the right angle meter cock using a copper or brass clamp. The other end of the tracer wire shall be bared and connected to the mains cock for metallic mains, or to the mains tracer wire on non-metallic mains. Non-detectable marking tape to AS 2648 shall be laid 150mm above all water services. Refer to Standard Drawing No. WSS 020 for details.

    Water services and meters shall be in free ground unencumbered by any surface obstructions such as concrete driveways, padmount transformers, streetlights, communication boxes, mini-pillars and retaining walls etc.

    The location of a service at the centre of a block frontage, or close (100 to 300mm) to the side boundary in the case of narrow frontages (but free from obstructions), will be acceptable to Icon Water. If the owner or a third party needs to place a surface obstruction over the service or meter, then the service and meter shall be relocated at their expense. Services shall be located so as to ensure easy access to the water meter by readers. Supply shall never be from the side or rear property boundary except for battle-axe blocks where the supply of services can be from the rear of the block.

    A service tapping shall never be closer than 1.0 metre from the flushing bend on a dead ended main. Zone valves that are normally closed are also considered as dead end mains.

    At boundaries between water supply pressure zones, care should be taken to ensure that services to individual blocks are connected to pipework serving the appropriate zone, and not to a main passing through the zone.

    New pipelines may utilise pre-tapped connectors for service connections, whereas existing pipelines shall use direct tapping (ductile iron pipe only) or approved tapping saddles (ductile iron and PVC pipe). Each service shall be individually tapped into the main where the minimum spacing between consecutive tappings shall be 1.0 metre. No tapping will be made closer than 300mm to a pipe spigot. DUAL SERVICES ARE NOT TO BE USED. 

  • 7 Irrigation systems

    The design of irrigation systems will generally be in accordance with the ACT Government Service document entitled Design Standards for Urban Infrastructure (Reference 10.4).

    Irrigation systems are regarded as a water service and as such are subject to the normal requirements for plan approval, permits and inspection procedures. Icon Water reserves the right to restrict draw-off rates and operating times when necessary.

    7.1 Irrigation systems

    • Systems irrigating more than 1 hectare should have an instantaneous draw-off not exceeding 3.5 L/s/ha.
    • Systems irrigating less than 1 hectare should have an instantaneous draw-off not exceeding 3.5 L/s.
    • In all cases the total volume of water used should not exceed 76 kL per night, per hectare of net watered area.

    TABLE 2-4
    Irrigation Rates and Times

    Area Application rate conditions Watering depth Time For watering

    Sections of watered area

    Maximum for any period

    10 mm/hr

    1 hr/night

    Net irrigated area

    Standard (use at least an 8 station controller)

    38 mm/wk

    40hrs/wk (l0pm to 6am for 5 days)

    Net irrigated area

    Severe drought

    50 mm/wk

    56hrs/wk (l0pm to 6am for 7 days)

    The above information, together with the pressures, should be noted on the final drawings to be submitted during Design Submission 2.

    7.3 Pressure enquiries Information on the pressure available within a reticulation system is frequently sought for the design of special services, usually fire protection or irrigation. Criteria covering the minimum pressures and flows available at points in a distribution system are given in Clauses 3.2 to 3.5. Even though there is no undertaking to provide higher pressures or flows than these, in many cases higher capacities or better pressures are available, especially outside peak demand periods. Estimates of expected pressures at selected draw-off points will be made by Icon Water in response to a writtenrequest. The request should state the magnitude (L/s) and type of demand (e.g. fire sprinkler, manually controlled irrigation, automatic irrigation), its location, and the period of the day over which draw-off is required. Requests should be forwarded to Icon Water and marked as 'Water Supply Pressure Enquiry'.

    7.4 Installation of pumps in private reticulation No pumps will be allowed to feed directly from Icon Water's mains system without written approval from Icon Water. Direct boosting from Icon Water's mains system is not permitted for residential dwellings. For commercial and industrial properties, direct boosting from Icon Water's mains may be permitted in some circumstances. In such cases the following particulars are required:

    type of pump; duty points; zero head discharge capacity of pump.

    Requests for pump approvals should be forwarded to Icon Water.

    7.5 Cross-connection to toher supplies All pipework, both public and private, shall be arranged so that backflow of water into the system from any source is impossible. For this purpose an air gap equivalent to at least twice the diameter of the discharge pipe shall be provided. This air gap will be positioned between outlets from Icon Water's system and any open storage vessel, or any pipework not containing a municipal water supply. Patented backflow prevention devices may be considered for approval in special circumstances, refer to AS/NZS 3500.

  • 8 Standards covering water supply practice

    Work carried out and testing performed under this clause shall comply with the requirements of the SAA Codes and Standards listed below, to the extent that these are relevant and cannot be overridden by Icon Water's Standards. Any queries are to be referred to the Manager, Water and Sewerage Assets.

    SAA Codes and Standards must include current amendments at the time of use.

    8.1

    Materials - DICL pipes and fittings

    AS 1646

    Elastomeric Seals for Waterworks Purposes (1992)

    AS 2280

    Ductile Iron Pressure Pipes and Fittings (1995)

    AS 3680

    Polyethylene Sleeving for Ductile Iron Pipelines (1989)

    AS 3681

    Guidelines for the Application of Polyethylene Sleeving to Ductile Iron Pipes and Fittings (1989)

    8.2

    Materials — PVC pipes

    AS/NZS 1477

    PVC Pipes and Fittings for Pressure Applications (1996)

    AS/NZS 4441 (Int)

    Molecular Oriented PVC (PVC-O) Pipes for Pressure Applications (1996)

    AS/NZS 4765 (Int)

    Modified PVC (PVC-M) Pipes for Pressure Applications (2000)

    8.3

    Materials — PE pipes

    AS/NZS 4129 (Int)

    Fittings for Polyethylene (PE) Pipes for Pressure Applications (1997)

    AS/NZS 4130

    Polyethylene (PE) Pipes, Pressure Applications (1997)

    AS/NZS 4131

    Polyethylene (PE) Compounds for Pressure Pipes and Fittings (1997)

    WSA 01

    Polyethylene Pipeline Code

    8.4

    Materials — steel pipes and specials

    AS 1281

    Cement Mortar Lining of Steel Pipes and Fittings (1993)

    AS 1548

    Steel Plates for Pressure Equipment (1995)

    AS 1579

    Arc Welded Steel Pipes and Fittings for Water and Waste Water

    AS 1646

    Elastomeric Seals for Waterworks Purposes (1992)

    AS/NZS 3678

    Structural Steel-Hot Rolled Plates, Floorplates and Slabs (1996)

    AS 4087

    Metallic Flanges for Waterworks Purposes (1996)

    AS 4321

    Fusion-Bonded Medium Density Polyethylene Coating and Lining for Pipes and Fittings (1995)

    8.5

    Valves and miscellaneous

    AS 1214

    Hot Dip Galvanised Coatings on Threaded Fasteners (ISO metric coarse thread series) (1983)

    AS 1432

    Copper Tubes for Plumbing, Gasfitting and Drainage Applications (1996)

    AS 1628

    Water Supply — Copper Alloy Gate, Globe or Non-Return Valves (1994)

    AS 2118

    SAA Code for Automatic Fire Sprinkler Systems (1982) (superseded in part by AS 2118.1-1995, AS 2118.9-1995, AS 2118.10-1995 and AS 4118.1-1995 and will remain current)

    AS 2419

    Fire Hydrant Installations, Part 1 (AS 2419.1) - System Design, Installation and Commissioning (1994)

    AS 2528

    Bolts, Studbolts and Nuts for Flanges and other High and Low Temperature Applications (1982)

    AS 2638

    Sluice Valves for Waterworks Purposes (1991)

    AS 3565

    Meters for Cold Potable Water, Part 1 (AS 3565.1) - Volumetric Chamber and Turbine Meters (1998)

    AS 3578

    Cast Iron Non-Return Valves for General Purposes (1991)

    AS 3952

    Water Supply - DN80 Spring Hydrant Valve for General Purposes (1996)

    AS 4020

    Products for use in Contact with Drinking Water (1999)

    AS 4087

    Metallic Flanges for Waterworks Purposes (1996)

    AS/NZS 4158

    Thermal-Bonded Polymeric Coatings on Valves and Fittings for Water Industry Purposes (1996)

    8.6

    Pipelaying and general construction

    AS 1170

    Minimum Design Loads on Structures, Part 1 (AS 1170.1) - Dead and Live Loads and Load Combinations (1989), Part 2 (AS 1170.2) - Wind Loads (1989), Part 3 (AS 1170.3) - Snow Loads (1990), Part 4 (AS 1170.4) - Earthquake Loads (1993)

    AS 1289

    Methods of Testing Soils for Engineering Purposes, Part 0 (AS 1289.0) to Part 7.1.3 (AS 1289.7.1.3) inclusive (various editions)

    AS 1302

    Steel Reinforcing Bars for Concrete (1991)

    AS 1303

    Steel Reinforcing Wire for Concrete (1991)

    AS 1304

    Welded Wire Reinforcing Fabric for Concrete (1991)

    AS/NZS 1462

    Methods of Test for PVC Pipes and Fittings, Part 1 (AS 1462.1) to Part 23 (AS 1462.23) inclusive (various editions)

    AS 1554

    Structural Steel Welding, Part 1 (AS/NZS 1554.1) to Part 6 (AS 1554.6) inclusive (various editions)

    AS 1650

    Hot Dipped Galvanised Coatings on Ferrous Articles (1989) (superseded in part by AS/NZS 4534 - 1998 but remains current)

    AS 1657

    Fixed Platforms, Walkways, Stairways and Ladders - Design, Construction and Installation (1992)

    AS 2032

    Code of Practice for Installation of UPVC Pipe Systems (1977)

    AS 2033

    Installation of Polyethylene Pipe Systems (1980)

    AS/NZS 2566

    Plastics Pipelaying Design (1982) (superseded by AS/NZS 2566.1 - 1998 but is still made available)

    AS 2648

    Part 1 (AS 2648.1) Underground Marking Tape - Non-Detect Tape (1995)

    AS/NZS 3500

    National Plumbing and Drainage Code (Part 0 to Part 4.2 inclusive)

    AS 3600

    Concrete Structures (1994)

    AS 3681

    Guidelines for the Application of Polyethylene Sleeving to Ductile Iron Pipes and Fittings (1989)

    AS 3725

    Loads on Buried Concrete Pipes (1989)

    AS 4100

    Steel Structures (1998)

    AS/NZS 4680

    Hot-Dip Galvanized (Zinc) Coatings on Fabricated Ferrous Articles (1999)

  • 9 Standard drawings

  • 10 References

    10.1 Water and Sewerage Regulations 2001 (ACT) and the Water and Sewerage Act 2000 (ACT) (having replaced the Canberra Sewerage and Water Supply Regulations 1999).

    10.2 Totalcare document, ACT Public Works Basic specification — roads, hydraulic services and landscape, edition number1 (July 1991) as amended (including in particular Corrigendum Number 1 to Volume 1, 11 December 1992) plus the associated Users guide for the basic specification.

    10.3 Icon Water, Water main connections — general conditions and schedule of charges, Current Edition.

    10.4 Territory and Municipal Services Department (2006), Design Standards for Urban Infrastructure: 21 Irrigation.

    10.5 Roads and Transport Section, ACT Department of Urban Services, Standard engineering practice — roads and bridges, draft number 5, 5 November 1995.