Technical requirements for sewerage

5. Structures and fittings

5.1 Maintenance holes

5.1.1 General

Maintenance holes are provided so that access to a sewerage system, for investigations, clearance of blockages and maintenance purposes, can be obtained.

They are necessary at locations:

• where there is a high risk of blockage (e.g. changes in direction, changes in grade, changes in size of pipe and changes in level);
• where junction structures are required to combine flows (e.g. with other sewers and with service ties DN150 and larger);
• at shallow points in the system (to form an emergency overflow relief path in times of acute hydraulic overload or blockage of the pipe system); and
• at regular intervals, for access.

Maintenance holes should be of a size and shape that provides reasonable access for personnel and equipment to flow channels, with a minimal likelihood of problems.

5.1.2 Materials and construction methods

Maintenance holes should be constructed so that they are structurally sound and do not permit ingress of water through the walls or joints. Maintenance holes should be resistant to erosion and corrosion.

The following construction methods have been approved:

1. In-situ concrete — the most common method of construction. The concrete is to have adequate cement content and be well compacted and cured.

   The shape of the maintenance holes can be either standard circular or of special shapes and sizes suitable for larger pipes and junctions. Special approval from ACTEW will be required for the use of non-circular shaped maintenance holes for sewers less than DN450.

2. Pre-cast concrete — maintenance holes utilising pre-cast concrete units have significantly more joints and therefore special care is required to ensure the joints do not form entry paths for tree roots and/or infiltration.

   Pre-cast maintenance holes shall be in accordance with Standard Drawing Nos. WSS 057 and WSS 058. Make-up neck rings are to be selected so that the neck length does not exceed 200mm.

   Pre-cast concrete maintenance holes shall be limited to a depth of 6.0 metres.

3. Other materials — where other materials such as Polyethylene (PE) or Glass Reinforced Plastics (GRP) are considered viable, written approval for their use in designs shall be sought from ACTEW.

   Where cast in-situ or pre-cast concrete maintenance holes are used, concrete shall be made with Type "SR" sulphate resisting cement having a tri-calcium aluminate content not exceeding 5%, or Type "LH" low heat cement to AS 3972.

   Standard maintenance holes will be provided with a step-iron access. Mild steel step-irons will be hot dip galvanised or be coated with an approved anti-corrosion agent.

5.1.3 Location

Access to maintenance holes may be required at any time of day or night, consequently they should be located where maintenance staff with machinery can obtain direct access at all times. Preference should be given to locating maintenance holes in public land rather than in leased properties. Unnecessary maintenance holes are to be avoided.

In roadway services maintenance holes should be located in positions where a measure of safety for maintenance staff is provided. Maintenance holes located in pavements are also likely to be covered over by re-sheeting of pavements during road maintenance. In conclusion, it is preferable not to locate maintenance holes in road pavements.

Maintenance holes must not be located in pavements at road intersections and roundabouts. Maintenance holes in road pavements shall have covers located in the middle of the slowest lane of traffic.

The preferred location of maintenance holes in roads is:

• within roadside verges;
• in footpaths;
• within median strips;
• in the centre of the slowest lane;
• maintenance holes must not be located in pavements at road intersections or roundabouts.

Where practicable, maintenance holes or shafts should not be located within driveways or on cycleways.

Maintenance holes also provide overflow points for sewage. Consequently, they should be located so that any overflow will be contained within acceptable flow paths such as road reserves or other public land.

5.1.4 Maximum spacing on straight sewers

General access is maintained on long sewers by providing intermediate maintenance holes. Maximum maintenance hole spacing is dependent on whether entry into the pipeline is possible. For pipelines of less than DN600 the maximum spacing is dependent on the type of equipment available to maintenance crews.

Acceptable maximum maintenance hole spacings are presented in Table 3-11.

Table 3-11
Maximum maintenance hole spacing — straight sewers

Pipe size (DN)	Maximum maintenance hole spacing (m)
150 to 450	100
525 to 900	150
1050 to 1650	300
1800 and larger	500

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5.1.5 Spacing on curves

It is considered that curved alignments will require more maintenance than straight alignments. Visual inspection from maintenance hole to maintenance hole is generally not possible. As a consequence closer maintenance hole spacing is required on these alignments.

Acceptable maintenance hole spacing on curved sewers shall be in accordance with Table 3-12. Maintenance holes shall be located on tangent points where the curve does not form a true tangent to the preceding or following straight.

Table 3-12
Maximum maintenance hole spacing — curved sewers

Pipe size (DN)	Maximum maintenance hole spacing (m)
150 to 450	80
525 to 900	100
1050 to 1650	300
1800 and larger	500

Notes

1. The combination of a single straight length and a single curve is acceptable. For purposes of maximum lengths between maintenance holes Table 3-12 shall apply.

5.1.6 Fall through maintenance holes

The fall through a maintenance hole is defined as the difference between the invert levels of the inlet and outlet pipes, measured at the inside face of the maintenance hole wall. Invert levels shall in all cases be at the inside face of the maintenance hole wall. Acceptable falls through maintenance holes are:

1. For DN150 sewers:
   1. For maintenance hole deflections less than 90º:
      • 30mm minimum;
      • 100mm maximum.
   2. For maintenance hole deflections 90º or greater:
      • 80mm minimum;
      • 100mm maximum.
2. For DN225 or DN300 sewers:
   • 30mm minimum;
   • 100mm maximum.
3. For sewers DN375 and larger:
   • Sufficient to maintain smooth laminar flow.

Irrespective of the above requirements, the grade shall not be reduced through the maintenance hole.

5.1.7 DN1050 Maintenance hole: Standard Drawing No. WSS 052

DN1050 maintenance holes shall be in accordance with Standard Drawing No. WSS 052.

DN1050 maintenance holes shall be used when:

• the outlet sewer diameter is DN450 or less; and
• the maintenance hole depth is less than or equal to 6.0 metres.

A minimum neck height of 100mm and a maximum neck height of 200mm is also required for ease of access.

Where maintenance holes are to be located in roadways the neck height shall be 200mm to allow for possible future level adjustment.

A permanent system for descending into the maintenance hole is to be provided. This will normally consist of step irons located over the outlet pipe.

The internal diameter of a DN1050 maintenance hole may not, in some instances, comply with channel radius requirements (Clause 5.1.11 (ii)), in which case either a DN1200 maintenance hole (Clause 5.1.8) or a special maintenance hole (Clause 5.1.9) will be required.

5.1.8 DN1200 Maintenance hole: Standard Drawing No. WSS 053

DN1200 maintenance holes shall be in accordance with Standard Drawing No. WSS 053.

DN1200 maintenance holes shall be used when either:

• the sewer size is in the range DN525 to DN675; or
• the sewer depth is in the range 6.0m — 8.0m; or
• where a larger structure is required to accommodate working space requirements as per Clause 5.1.11 (iii).
• in situations where a special maintenance structure (Clause 5.1.9) is not warranted.

Sewer maintenance holes for these situations need to be larger in diameter, compared to the DN1050 maintenance hole, to provide better access and more working room for specialised equipment.

DN1200 maintenance holes shall have a minimum wall thickness as shown in Table 3-13.

Table 3-13
Minimum wall thickness — DN1200 maintenance holes

Depth range (mm)	Minimum wall thickness (mm)
0 to 6.0	150
6.0 to 8.0	225

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5.1.9 Special maintenance holes

Where the outlet pipe diameter is greater than 675mm, the depth is greater than 8.0 metres, or channel radius requirements (Clause 5.1.11 (ii)) cannot be accommodated by either the DN1050 or DN1200 maintenance holes, then either a large diameter maintenance hole or a special chambered maintenance hole shall be used.

1. Large diameter maintenance holes: DN1500 to DN1800

   Large diameter maintenance holes shall generally be DN1500 to DN1800 unless prior approval has been given to use other sizes.

   The configuration of large diameter maintenance holes shall be based on the ladder or step-irons being placed above the benching rather than over the outlet pipe (refer Clause 5.1.11 (iii) for details). The appropriate diameter of the structure can be determined by sketching out the angles and junction flow requirements.

   Large diameter maintenance holes will require a reinforced concrete flat-top cover, and access shall be through a short neck section. Class D, sealed (gastight) solid-top metal access covers shall be provided.

   Large diameter maintenance structures will incorporate the above features and shall be shown in detail on the design drawings for ACTEW approval.

2. Special chambered maintenance structures

   The configuration of special chambered maintenance structures shall be based on the ladder or step-irons being placed above the benching rather than over the outlet pipe (refer to Clause 5.1.11 (iii) for details).

   The appropriate inside dimensions of the maintenance hole can be determined by sketching out the angles and junction flow requirements. The minimum structure length shall be 1.5 metres. For sewers DN675 or larger the structure shall be provided with handgrips above the PDWF to facilitate safe access into the benching channel.

   Special chambered maintenance structures will require a reinforced concrete flat-top cover, and access shall be through a short neck section. Class D, sealed (gastight) solid top metal access covers shall be provided.

   Special chambered maintenance holes will incorporate the above features and shall be shown in detail on the design drawings for ACTEW approval.

5.1.10 Ladders and landings for deep maintenance holes or structures

For maintenance holes deeper than 6.0 metres, ladders and intermediate landings shall be required. The minimum headroom to the underside of all landings shall be sufficient to permit maintenance personnel to stand erect under the landing. Generally, the minimum acceptable headroom will be 2.1 metres. The level of the top face of each landing shall be shown on the detailed design drawings. Ladders and landings shall be stainless steel as shown on Standard Drawing No. WSS 002. Alternative corrosion resistant materials will be considered provided details are submitted to ACTEW for written approval.

5.1.11 Benching

1. Depth of benching

   To minimise stranding, hydrogen sulphide generation, and hydraulic losses through the maintenance hole, a channel is to be formed within the maintenance hole base to provide a smooth flow transition.

   For sewers up to and including DN375, the bench shall be up to the obvert level of the inlet pipe. The maximum depth of benching in these small diameter sewers shall be 400mm.

   For DN450 sewers, the bench shall be to a minimum depth of 400mm.

   For sewers larger than DN450 the trench shall be at the mid height of the highest incoming pipe + 100mm, or to a depth of 400mm, whichever is greater. Where benching depth exceeds 600mm and space allows, a step-down shall be provided in the benching. The step shall:

   • be 225mm x 225mm in plan;
   • self-drain into the sewer at 2%;
   • be at least 400mm above the invert;
   • be located on the inside of the curve, near the hand-holds.

   For pre-cast concrete maintenance holes, the bench shall be 100mm above the incoming pipe to allow for an effective seal against infiltration.

2. Radius of benching

   Changes in direction at a maintenance hole or special chamber shall be accommodated entirely within the structure. This shall be achieved by a curved channel of uniform radius.

   A desirable minimum internal benching radius is 2.5 times the nominal diameter (DN). Benching curves on Standard Drawing No. WSS 062 have been selected to minimise hydraulic losses and to allow access by CCTV equipment. Parameters for intermediate angles can be interpolated from these drawings.

   (refer also Standard Drawing Nos. WSS 052 and WSS 053).

3. Minimum working space

   A minimum clearance of 375mm benching space, both in front of or next to the step-iron or ladder access, and 225mm on the opposite side of the channel, is required to provide adequate working space. This will generally require offsetting the centre of the structure to the sewer pipes. For offsets on commonly found configurations refer to Standard Drawing No. WSS 062. For non-standard configurations, details of the offset layout shall be submitted in Design Submission 2 (as per Clause 5.1.12).

5.1.12 Offset of maintenance hole centreline

To accommodate a change of direction at maintenance holes, to meet benching and maintenance space requirements, it is required that maintenance holes be "offset" . The key criteria to be accommodated are outlined in Clause 5.1.11.

Maintenance hole offset requirements for standard pipe configurations in DN1050 and DN1200 maintenance holes are shown on Standard Drawing No. WSS 062.

Details of the offset layout shall be submitted in Design Submission 2.

For non-standard configurations this will include a 1:20 scale plan of each maintenance hole showing:

• internal diameter;
• channel benching and invert centre lines;
• offsets necessary to position the maintenance hole in relation to the pipeline intersection point;
• step-irons or ladders;
• external drops;
• platforms (if any), and clearance beneath and above the platform.

5.1.13 Junction maintenance holes

Maintenance holes are to be constructed where sewers, or property ties of DN150 or larger, form a junction with a main sewer. The maintenance hole junctions are to be designed to provide a smooth flow transition from the branch sewer, and to maintain a free air path through the maintenance hole for all flows less than the PDWF. The designer shall ensure that deep flows up to the PWWF in the major line do not result in surcharging of the branch line.

Inlet and outlet pipes must be set at levels relative to each other such that flows do not stagnate in any of the connected pipes. Channel benching on all branch sewers shall be graded to ensure smooth flow transition from inlets to outlet.

These requirements should be achieved using Table 3-14 and Table 3-15. When utilising Table 3-14, note must be taken of data in Table 3-15 which takes precedence for minimum falls across maintenance holes.

Table 3-14
Branch-to-main sewer connections

Notes

1. OL = pipes connected obvert level to obvert level.
2. CL = pipes connected centreline to centreline.

Where both sewers are larger than DN300, the design of junction angles shall incorporate sound hydraulic principles to limit turbulence and hydrogen sulphide emissions. A suggested method of "balanced lateral momentum" is given in The Control of Sulphides in Sewerage Systems (Reference 10.3). ACTEW may request to review these calculations and sketch layouts during Design Submission 2.

Table 3-15
Difference between branch and main sewer invert levels at maintenance holes

(1) Both sewers with similar hydraulic loads. (2) Branch sewer collecting 5 or less residential dwellings.

Notes

1. The minimum fall in Table 3-15 shall be defined as the difference between the branch inlet invert level and the maintenance hole outlet invert level, measured at the inside face of the maintenance hole.

5.1.14 Vertical drops

1. Drop pipe configurations

   Generally, drops are used to connect shallow branches to deep mains or to avoid other underground services. Major changes in level are achieved by using a vertical drop pipe integrated with the maintenance hole structure (normally external to the main chamber). The requirements for the design of the drop are:

   • the pipe shall not be liable to blockage at either the top or the base;
   • easy to maintain (ie. clearing of any blockage);
   • ability to convey flows without splashing or undue turbulence; and
   • not to be intrusive on the working space in the maintenance hole.

   Vertical drops are usually achieved through the use of a DN1050 or DN1200 (Standard Drawing Nos. WSS 052 and WSS 053) maintenance hole with external vertical drop.

   The limitations on the arrangement are:

   • the drop pipe is restricted to a maximum size of DN375 (refer also (b) below);
   • the invert level of the inlet pipe shall be at least 675mm below the bottom of the tapered cone.

   Sewers should be graded out to avoid drops not in accordance with the above. See Standard Drawing Nos. WSS 052 and WSS 053 for drop details.

   1. DN100 to DN375 incoming high level sewer

      Drop pipes are to be as shown on Standard Drawing Nos. WSS 052 and WSS 053. The minimum fall between the invert level at the base of the drop and the outlet pipe shall be 50mm.

   2. DN450 and larger incoming high level sewers

      Drops for sewers larger than DN375 shall be designed as special structures, such as vortex drops, to ensure satisfactory dissipation of energy.

2. Pipe support to branch lines

   The inlet pipes for maintenance holes with vertical drops are laid over a section of backfill. Consequently, they have a tendency to fracture when settlement of the backfill occurs. To limit this problem special attention shall be given to ensure adequate compaction under the inlet pipe. In addition the pipes are to be designed to allow for some settlement.

   The first section of the inlet pipe upstream of the maintenance hole shall be constructed from DICL, with two 600mm lengths of standard pipe added immediately thereafter. The ductile iron pipe shall be long enough to span the backfill section.

5.1.15 Standard covers

Sewer maintenance holes are to have standard size reinforced concrete seating rings and lids. This is so that they can be readily identified, opened using currently available maintenance lifting gear, and be readily replaced from existing stock while ensuring compatibility between lid and ring.

Only Class B (AS 4198) concrete covers and matching surrounds are to be used. These covers are to meet dimensions nominated in Standard Drawing No. WSS 058. Class B covers and surrounds shall be used in all applications other than those itemised under Clause 5.1.16.

For seating ring and surround fixing requirements in standard cover applications refer to Standard Drawing No. WSS 053.

 

5.1.16 Metal access covers

The covers of sewer maintenance holes which are subject to:

• internal surcharge loading; or
• are within 100 metres of the receiving point of pumped flows; or
• are subject to external vehicle loads; or
• are installed in areas lower than the expected 100 Year ARI flood level; or
• are installed in poorly ventilated areas; or
• are installed on sewers greater than DN300; or
• are installed in areas which are mowed using tractor mowers; or
• are installed in areas likely to experience ponding due to lack of drainage;

shall be Class B, C or D in accordance with AS 3996.

These covers and surrounds shall be specified as SEALED (watertight and gastight) solid top, and be used as follows:

1. Maintenance holes in pavements:
   • Road carriageways (Class D);
   • Public car parks or residential driveways (Class D);
   • Driveways in industrial areas (Class D generally, but higher may be required in some circumstances, e.g. airports etc.);
   • Paved pedestrian city areas (Class C);
2. Maintenance holes on sewers larger than DN300, or deeper than 6.0 metres, or those which receive pumped flows (Class B minimum, Class D when subject to traffic loading);
3. Maintenance holes may require bolt-down locking to resist internal surcharges, in this case stainless steel bolts are to be used to secure the cover to the seating ring. The seating ring is to be structurally secured to the maintenance hole chamber. This is required for:
   • Maintenance holes at the bottom of steep (supercritical flow) sections (Class B minimum, Class D if trafficable);
   • Maintenance holes with cover levels below the 100 Year ARI flood level (Class D).
4. Areas which are mowed using tractor mowers (Class C minimum, if area is likely to serve as car parking Class D).

Cast-iron covers shall be "GATIC" , or of an "approved equivalent" type, so that they can be readily interchanged from existing or new stock if damaged.

For seating ring and surround fixing requirements in metal access cover applications refer to Standard Drawing No. WSS 053.

 

5.1.17 Maintenance hole cover levels

Maintenance hole cover levels shall be designed to ensure that the cover can be easily located by maintenance personnel while not creating a hazard.

It is preferred that maintenance hole covers be located above the 100 Year ARI flood level. No cover shall be lower than the 2 Year ARI flood level. Covers can be located between the 2 Year and 100 Year ARI levels provided:

1. The maintenance hole cover and surround are bolted down to withstand internal surcharge pressure and external water drag (refer to Type 5 fixing detail on Standard Drawing No. WSS 053).
2. Dry vehicular access is available up to the maintenance hole for all flood events smaller than 2 Year ARI.

Covers and surrounds must be graded to:

• maintain surface tolerances suitable in maintaining driving comfort;
• minimise transfer of horizontal dynamic wheel loads to the maintenance hole;
• prevent pedestrian trip and slip hazards;
• maintain ease of location.

Maintenance holes located beneath finished surfaces are generally not permitted. In situations where sewers cross playing fields or golf fairways the designer should discuss the alignment issues with ACTEW during Design Submission 1.

Steeply sloping covers are unsatisfactory for maintenance reasons. Where finished surfaces have slopes greater than 1 in 8 the cover, and an adjacent area sufficient to lay the removed cover, shall be no steeper than 1 in 8.

Acceptable finished cover levels shall be:

1. paved areas — flush with finished surface;
2. footpaths and bicycle tracks — flush with finished surface;
3. plantations already established and grassed — 25mm above surface (see note 1);
4. elsewhere — 75mm above surface to allow for topsoil and grassing (see note 1).

Notes

1. To remove trip hazards and to reduce horizontal forces on the cover, fill should be placed and compacted around the raised surround and graded down to the natural surface at a slope of 1 in 10.

5.1.18 Surface clearance to covers.

To maintain accessibility a minimum horizontal clearance of 1.0 metre from the edge of the cover in any direction must be assured. No major tree planting or structures are permitted in this zone (refer also to Clause 2.3).

5.1.19 Maintenance holes receiving pumped flows

Maintenance holes receiving pumped flows via a rising main are frequently subjected to hydrogen sulphide corrosion and therefore require special consideration.

For receiving maintenance holes less than 6.0 metres deep the receiving structure shall be designed to minimise turbulence, and shall be located adjacent to the receiving gravity main (refer Standard Drawing No. WSS 055). The short gravity pipe between the receiving maintenance hole and the gravity main shall be designed to (1) minimise turbulence within the gravity pipe, and (2) prevent gravity flows entering the rising main. This section of the sewerage system shall be of a material not subject to hydrogen sulphide corrosion (refer to Clause 7.2).

Ventilation should also be incorporated into receiving maintenance holes and the first maintenance hole immediately downstream. Receiving maintenance holes are to be internally coated with approved epoxy.

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5.2 Sewer maintenance shafts

Maintenance shafts permit maintenance and monitoring equipment to be inserted into the mains but do not allow maintenance personnel access. These maintenance shafts are typically of size DN225, are vertical, and are enlarged at the base to cater for long objects entering the sewer. The top of the shaft has a rubber ring sealed cap. A conventional cover is placed on top to protect the shaft from surface loads. Maintenance shafts offer four key benefits:

1. they are substantially cheaper than maintenance holes;
2. they reduce the safety risks associated with conventional maintenance holes;
3. they involve less excavation impact;
4. they are more resistant to groundwater infiltration.

Maintenance shafts can be used in lieu of maintenance holes within the following constraints:

• only ACTEW approved shaft products will be installed as per Standard Drawing No. WSS 061;
• shafts shall only be used on DN150 and DN225 mains;
• the maximum spacing between conventional maintenance holes shall not exceed 160 metres, the distance between a maintenance shaft and the nearest maintenance hole shall not exceed 80 metres;
• maintenance shafts shall not be used at sewer main branch junctions but may be used to accept property connections;
• maintenance shafts shall not receive pumped flows;
• the maximum sewer deflection shall be limited to 55°, this represents the sum of the deflection through the shaft and one or two external bends. The maximum deflection through the shaft chamber must not exceed 45°;
• the maintenance shaft cap shall not be bolted or screwed down of relief should the sewer surcharge. The cap must always be above the 100 Year ARI flood level;
• a maximum of two bends can be used outside the shaft chamber, one at the inlet and one at the outlet. The bends and shaft must deflect in the same direction;
• the fall of the maintenance shaft is fixed at between 2% and 3%, and the access shaft must always be installed vertically. To eliminate undue turbulence in the shaft chamber, and to assure join deflections are not exceeded, maintenance shafts shall not be used if the grade of the upstream or downstream sewer exceeds 5%;
• pipe connection to the shaft shall be made using rubber ring connectors or where material allows by means of solvent welding. If reducers are required they shall be eccentric tapered reducers.

5.3 Other special structures

The design of other sewerage structures such as siphons, vortex drops etc. are not covered in this document and shall be referred to ACTEW for detail requirements.

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6. Service connections

6.1 Lease drainage

The sewerage system shall be designed so that waterborne wastes can be efficiently removed from each lease. The design should allow for probable site earth works consistent with the nature of likely site development, for example the creation of large level areas for industrial or commercial buildings.

Increasing the depth of sewers external to leases at extra public cost in order to permit gravity drainage of basement fixtures within specific leases is not normally permitted. Basements will be required to be serviced by sullage pumps to prevent risk of backflow and flooding from external mains.

For design of service ties see Clause 6.2.

An acceptable design shall provide service connection ties to suit the individual needs.

6.2 Service ties (house connections)

A sewerage service tie is to be provided for each leased block (see Clause 6.1).

6.2.1 Depth of tie

A service tie is required to serve the entire leased block. However, where building restrictions do not permit part of the block to be developed (e.g. setback distances from the front building line), then depths may make allowance for this limitation.

In calculating the depth requirements, the designer should be familiar with the various requirements for grade, depth and special structures provided for in the Water and Sewerage Regulations 2001 (Reference 10.1) and AS/NZS 3500.

Allowance should be made for any possible earthworks that may occur during the development of the site (e.g. providing driveways and/or a level area for buildings). For industrial blocks, where considerable earthworks are normal practice, this allowance is particularly important.

An acceptable design will have the following minimum depths of tie:

• for residential blocks: calculated on the basis of a minimum cover of 600mm and a maximum possible length of house drain at a grade of 1 in 60;
• for industrial and commercial blocks: calculated on the basis that the whole of the building zone is excavated to the lowest level of the building zone, and with minimum cover, lengths and grade as above. Where the effect of providing the excavation requirement involves substantial lowering of the sewer (e.g. greater than 1 metre for more than 500 metres downstream), the matter shall be referred to ACTEW for resolution;
• 750mm of cover if located in road reserves, or 600mm of cover if located within blocks.

The maximum permissible depth of a sewer tie is 2.5 metres.

6.2.2 Location

A service tie connecting to a sewer outside the leased block should generally be at right angles to the sewer. Where a service is to a maintenance hole or "dead-end" , the service shall be at an angle between 90° and 180° from the downstream sewer to ensure a smooth flow of entry into the main line.

Service ties shall be located clear of driveways and retaining walls unless specifically approved by ACTEW.

Where the sewer is located outside the leased block, the tie shall terminate just inside the property line.

Where possible, the tie should generally be located on the sewer at 1.0 metre from the lowest corner of the property. However, it is permissible to locate the tie at a position other than the lowest corner of a residential block provided that.

• no more than fourteen (14) residential dwellings, and
• no non-residential leases,

are serviced upstream of that block. In such circumstances, particular attention must be paid to the requirements of Clause 6.2.1 regarding the maximum permissible depth of a sewer tie, and also to the requirements of Clauses 4.2 and 6.2.1 relating to the servicing of an entire lease.

The upstream end of any "dead end" sewer shall extend to at least 1.0 metre past the block boundary to accommodate a service tie (for "dead ends" refer to Clause 3.3).

Where practical, a service tie should discharge directly into a maintenance hole in lieu of a separate branch connection to a sewer.

Service tie locations shall be as per Standard Drawing No. WSS 054. The tape shall be nominally 75mm wide and coloured "cream" to AS 2700 in accordance with AS 2648.

No more than three (3) consecutive service ties on a reticulation main are permitted to cross a roadway unless specifically approved by ACTEW.

6.2.3 Size of tie

Sewer service ties are normally DN100 rubber ring jointed or solvent welded pipes. For multiple dwellings a single tie is to be provided per property. In certain circumstances a larger connection might be required for a large or special site e.g. commercial and industrial sites. In such cases the tie should be sized to cater for the hydraulic requirements in accordance with the Water and Sewerage Regulations 2001 (Reference 10.1) and AS/NZS 3500. If the service tie is DN150 or larger it shall be connected to a sewer maintenance hole.

6.2.4 Grade

The service tie shall have a minimum grade of 2.0%, generally a maximum grade of 100%, and terminate in a sealed pipe socket.

For ties to deep sewers, 45° jump-ups or buried vertical risers may be used (refer to Standard Drawing No. WSS 054).

6.2.5 Connection of DN100 Service Ties

Service tie connections into sewers of DN150 to DN300 may be by the means of a 60° rubber ring jointed slope junction, a 30° bend, and a length of pipe (refer to Standard Drawing No. WSS 054 for details). The pipe length is to be sufficient to extend to at least the property boundary, and to a maximum of 600mm within the property. The end of the service is to be sealed.

Service tie connections into DN375 to DN600 sewers are to be directly into maintenance holes. Where additional maintenance holes are required to comply with this arrangement, or the sewer is deep, a parallel, shallower "pick-up" sewer may be advantageous.

6.2.6 Buried Vertical Riser (BVR)

On deep sewers that are near boundaries it may be necessary to use a BVR. These are to be noted on drawings and constructed as per Standard Drawing No. WSS 054.

It is absolutely critical that BVR's are installed on a compacted trench base with suitable concrete support.

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7. Design criteria for small pump stations and rising mains

7.1 Small pump stations

7.1.1 General considerations

ACTEW has a preference for gravity sewerage systems because of the ease of operation and the minimisation of hydrogen sulphide corrosion of the sewers. For systems that will be owned and operated by ACTEW, sewage pumping should only be adopted where shown on ACTEW's Sewerage Strategy Plans, or after discussion and agreement with ACTEW regarding the economics of pumping versus other alternatives.

The design of pump stations is heavily influenced by the locality. There is no single set of standards that can apply to all locations. Standard Drawing No. WSS 055 has been prepared to provide basic guidelines in the design of each station. It is recommended that the agent consult ACTEW at the earliest possible time to quantify site specific issues relating to proposed sewer pump stations.

Sewage pumping may be appropriate:

• where sewerage facilities are required to serve developments that cannot drain to existing or proposed gravity systems;
• to prevent excessive depth of sewer lines in flat terrain (not generally the case in Canberra);
• to provide surcharge relief on overload sewerage systems by transfer to a different catchment;
• to lift sewage into a sewage treatment plant.

The following general requirements are for small neighbourhood pump stations intended to be owned and operated by ACTEW, and which handle PWWF's up to about 50 litres per second. The more detailed aspects of station design should be discussed with ACTEW at an appropriate stage during design.

For stations larger than 50 litres per second, design requirements will normally be specified in an ACTEW brief tailored to the individual project.

Where a proposed pump station is associated with a single specific lease, and the station and rising main are to remain the responsibility of the lessee, ACTEW's main concern will be to ensure that the design and operation of the station and rising main are such as to prevent hazardous conditions, corrosion, or odour problems within the receiving ACTEW system.

7.1.2 Station catchment and siting

The station location and duty shall be based on the service areas shown on ACTEW's Sewerage Strategy Plans using flow estimating procedures as set out in Clause 3.1.1.

The siting and depth shall be chosen to command the service areas by gravity while allowing adequate incoming grades. In determining station depth, it is important that the constraints governing wet well depth be clearly identified, and excessive depth be avoided. Measures such as concrete encasement of gravity sewers under roadways and floodways to reduce depth of cover, and in appropriate cases relaxation of "slime control" criteria for critical sewers (refer Clause 3.1.3 (i)), should be used.

Station siting shall provide optimum integration of the station with adjacent land uses, landscaping, all weather access, hardstand areas for maintenance vehicles, and satisfactory overflow arrangements. Minimum turning radii around the station and access tracks shall be suitable for an 8.8 metre service vehicle as per Austroads Standards Australia — AS HB72. The vehicle must be able to be reversed or driven to enable parking (with the rear or side of the vehicle next to the well). Access track grades steeper than 2% shall be cement stabilised, and tracks steeper than 5% must be sealed. In areas where the station is at the end of a dead-end access, the hardstand must allow for the truck to be turned around within the pavement area.

Security fencing shall enclose the key components. Appropriate warning signs shall be visible.

Designers should be aware that the noise of mechanical equipment may cause irritation to adjacent residents. Keep stations well away from adjacent residential development and/or provide appropriate soundproofing. Covers and vents that are prone to flooding or are required for station access during floods shall be above the 100 year ARI flood level of any adjacent waterway or pond. Siting should attempt to minimise pump station, gravity and rising main costs, and ensure economic and timely availability of power supply, telephone and town water connections necessary for commissioning and operation.

7.1.3 Design objectives

The overall objectives for sewage pump station design are as follows:

• safe working conditions for operations and maintenance personnel;
• ease of accessibility and operation;
• long term reliability;
• minimum capital, and operating and maintenance costs of the station, gravity mains and rising mains;
• unobtrusive location;
• energy efficiency.

With the exception of temporary facilities intended to be superseded within a few years, station components shall be designed for the following design lives:

• Civil works — 100 years;
• Electrical and mechanical equipment — 15 to 25 years.

Works shall make appropriate provision for initial and foreseeable future design loadings. The economics of staging, temporary cut-off walls or curtailments, initial use of reduced impeller sizes, or planned upgrading of the pump capacity should be considered.

For ease of maintenance, and in minimising stores inventories, equipment should be of standard types. The equipment should be interchangeable with, or preferably identical to equipment incorporated into existing ACTEW stations. Designs incorporating new or unusual equipment require the prior approval of ACTEW.

7.1.4 Station arrangement and services

For stations up to 50 L/s capacity, unless there are good reasons to the contrary and prior written agreement from ACTEW is obtained, a single wet well configuration with submersible centrifugal pumps should be adopted. Valves and meters shall be housed in isolated chambers at shallower levels.

These stations should be oriented such that the incoming line is perpendicular to the axis of the pumps. The valve chamber shall be integral with the wet well, and located on the side opposite the incoming sewer for cast in-situ construction. For pre-cast wet wells, the valve pit is located adjacent to the wet well. Switch and control gear shall be located such that access to the wet well or valve pit does not interfere with the operation of the station.

Water supply shall be provided for washdown purposes and shall terminate in a 25mm quick coupler connection. To prevent cross-contamination of the town supply, an approved backflow preventer shall be fitted in accordance with the Water and Sewerage Regulations 2001 (Reference 10.1) and AS/NZS 3500. A telephone connection is required for telemetry of remote alarms.

Power supply, switching, control, and telemetry equipment should be located in a vandal-proof, above ground, painted metal kiosk.

Permanently installed lifting equipment is not required for individual loads less than 500kg. For heavier loads, permanent lifting facilities (such as gantries or booms) shall be provided.

Adequately drained hardstand areas shall be provided, and shall be of a size sufficient for two service vehicles. Access covers to wet well and valve pit(s) shall be arranged either to prevent vehicle access, or designed for vehicle loadings.

Excessive flows, blockages, and operational failure of the pump may occur, dictating the need to provide an overflow for incoming sewage. The overflow pipe can be located in the collection maintenance hole, with the invert level located above the obvert level of the incoming sewer pipe. Suitable means of disposal of the flow from the overflow pipe is generally site specific, and shall be discussed with ACTEW and the Environment ACT at an early stage in the design. In general, overflows shall not be permitted to enter leases, and should be collected by the stormwater drainage network as soon as practicable. The overflow pipe outlet shall be arranged to prevent stormwater from entering the sewer system up to the 100 Year ARI flood level of any adjacent watercourse or waterbody.

In general all components of the station which require manual handling shall be designed to conform with the ACT Standard and Code of Practice on Material Handling (Reference 10.14).

7.1.5 Station capacity and pumping units

Pump configurations should be:

• two fixed speed pumps each sized for PWWF; or
• three pumps each sized for 50% of PWWF; or
• two variable speed pumps each capable of PWWF.

Pumps and motors shall be sized to handle the full range of flows and delivery heads expected to be encountered (including wet well levels varying between minimum operating and "flood" levels). Flood levels shall be calculated as the maximum level in the wet well to which incoming sewage can surcharge (including due to flooding of any adjacent watercourse). Units shall be selected for optimum efficiency under the most commonly expected average flow conditions. Motors shall be non-overloading for free discharge. Details on the preferred pumps should be obtained from ACTEW prior to the start of the final design.

Impellers shall be of the "non-clog" type capable of passing DN75.

Each pump shall be provided with a re-circulation flush valve, which mixes the sludge that accumulates at the base of the pumps. Details on the preferred flush valves should be obtained from ACTEW prior to the start of the final design.

7.1.6 Station inlet

Pump stations shall be provided with a single inlet pipe. Sewage from additional pipes may enter the station via the collection maintenance hole located adjacent to the station.

Provision for isolating the station from incoming gravity flows is required to permit maintenance or other works to be undertaken. This is usually achieved via a penstock (or knife-gate valve) located on the end of the inlet pipe within the station. The penstock shall be operable from the surface via an extension spindle manufactured from a non-corrosive material (preferably stainless steel 316L).

7.1.7 Wet well

All structures to be designed to accommodate appropriate structural loads as outlined in AS 3735 and AS 1170. The station will be provided with appropriate brackets to enable erection of safety equipment over the well. Details are to be obtained from ACTEW prior to design taking place.

The volume of the wet well is a function of the incoming sewage flow rates and the pump capacity. Where feasible, the wet well volume between switching levels shall be sufficient to limit pump starts, under any conditions, to 12 per hour.

The active volume of the wet well may be determined from the following formula:

• WV = (900 x Qp)/S

where:

WV = wet well volume (L)

Qp = pump capacity (L/s)

S = number of starts per hour

Switching levels shall be as follows:

1. Bottom water level (BWL)

   The BWL is to be set as low as possible (to minimise dead storage), while still maintaining sufficient submergence to provide adequate suction head at the pump inlet, and to prevent any vortex actions. For small pumps the BWL may be set approximately one quarter of the way up the motor housing. For larger pumps the manufacturer will need to be consulted.

2. Top water level (TWL)

   The TWL is defined by the volume between this level and the BWL (required to limit pump starts to the maximum permitted number per hour). The duty pumps are switched on at this level.

3. Maximum top water level (MTWL)

   The MTWL is set 150mm below the invert level of the incoming sewer pipe. The standby pumps are switched on at this level.

The shape of the wet well shall incorporate the following features:

• benching of the base of the wet well (to direct flow to the pump suction);
• adequate (but not excessive) clearance between the pump inlet and the base of the wet well (to enable removal of solids and to provide efficient pump operation);
• reduction in the plan area of the wet well below the minimum water level needed for pump operation (to optimise pump efficiency);
• sufficient area to install machinery to the tolerances required by the pump manufacturer (to enable the operation of level regulators and permit access via ladders);
• access to the wet wells of pump stations is required for cleaning, removal of obstructions and maintenance or replacement of pumps and level regulators. Consideration shall be given to maintenance access to the bottom of the wet well. Means of access shall include movable ladder extensions with suitable brackets for extensions as required (refer to Standard Drawing No. WSS 023), and ladders permanently fixed within the wet well. Where ladders are used, these shall be manufactured from a non-corrosive material, preferably stainless steel 316L. The maximum length of any ladder is to be 6.0 metres, with landings required at 6.0 metre intervals for deeper wells. A vertical clearance of 2.1 metres shall be provided beneath each landing.

Openings shall be provided in the concrete roofs of pump stations (designed to facilitate the installation and removal of pumps). The covers fitted to a pump station shall be sealed (gastight) metal covers, Class B (Class D if trafficable). Elsewhere covers shall be made from aluminium.

Plate covers shall be hinged, and a post (or similar) provided to rest the opened covers. Covers shall be light enough to be lifted by one person. The top of the structure shall have no projections that constitute a trip hazard. All locks and hinges shall be recessed.

The wet well will be provided with an automatic well washing system. The wash cycle is to parallel each pump cycle. Details on the preferred well washing systems should be obtained from ACTEW prior to design taking place.

The well shall be painted with grease repelling epoxy.

7.1.8 Pipework

Pipework shall be designed to suit the pumping units and to comply with the following:

• reflux valves shall be provided on the discharge side of each pump;
• isolating valves shall be provided on suction lines (on the discharge side of each pump downstream of the reflux valve), on any cross connections, to permit operation of any one pump independently of other(s) removed for maintenance, and on the rising main(s) immediately downstream of the junctions of discharge lines from the individual pumps;
• dismantling joints shall be provided to permit piecework within the station to be removed consistently with normal maintenance requirements;
• pipework shall be sized to give a minimum velocity of 1.0 metre per second. Maximum velocities shall be arranged to prevent undue abrasion of pipe linings or excessive headloss;
• a drainage line shall be provided allowing sewage within the rising main to be emptied into the pump station (to facilitate maintenance on the rising main).

7.1.9 Mechanical equipment

All parts shall be accessible for maintenance and replacement. Allowance shall be made in the design of equipment for wear and tear, including that due to pumping of abrasive solids. Provision shall be made for any necessary adjustments.

7.1.10 Electrical equipment

All pump stations are to be equipped with the following:

• electricity supply meter: records the energy consumption of the total pump station;
• power supply unit: this distributes power to all the control and starter units, with power generally being 3 phase 415 volts. The features of the unit are the main switch, voltmeter, phase failure relay LED, and circuit breakers;
• common auto control unit: this unit houses all the control equipment for the automatic operation of the station. Components within this unit include the duty selector switch, top water level override button, maximum top water level override button, and the flood level indicating light;
• motor starter units: these units control each pump and house all of the motor protection equipment and alarm lights. The components include the control selector switch, thermal overload indicating light, thermistor LED, seal failure light, seal failure reset button, ammeter, hours run meter, and the number of starts meter;
• an hours run meter and ammeter for each pump;
• telemetering unit;
• programmable logic controller (PLC) to ACTEW specification;
• auxiliary board: includes a twin 10 ampere general purpose outlet and a light switch to turn on the internal fluorescent tube.

The programming of the PLC's will be carried out by ACTEW at the developers expense prior to the handover, the developer needing to make the necessary arrangements with ACTEW for this to occur.

7.1.11 Flow metering

Flow metering requirements shall be obtained from ACTEW prior to commencing design.

7.1.12 Protection and alarms

Protection and alarm requirements shall be obtained and verified by ACTEW prior to commencing design. At most locations ACTEW will request that a security system be installed.

In environmentally sensitive locations the Environment ACT may require that emergency storage and or backup generators be provided adjacent to the pump station.

If storage or generators are considered necessary, the degree of protection required will be determined by the locality of the station and the nature of the receiving water body. Some guidelines on integration of storage tanks to pump stations is provided on Standard Drawing No. WSS 055. Storage structures introduce maintenance constraints, ACTEW should be consulted during the planning and design to assure that the technology implemented complies with ACTEW's operating and maintenance capability.

7.1.13 Ventilation

For small wet well pump stations with submersible pumps, natural ventilation of the wet well using ash-down vents is generally adequate, however, such ventilation may not be appropriate for sites where public access is likely. In such localities tall mechanised vents will need to be constructed to ensure gasses are adequately dispersed. In very sensitive areas such as public parks, and sites in close proximity to residential leases, odour scrubbing may need to be considered.

Stations or tanks deeper than 6.0 metres, or those that exceed a total internal volume of 50m3, will be fitted with a DN375 PVC pipe attached to the wall of the station. This pipe will extend from beneath the cover slab surface of the station to 200mm above the MTWL. A DN400 metal cover will be constructed directly above the DN375 conduit, a second DN600 metal cover being provided on the opposite side of the station. This system will be used in conjunction with a portable fan to force out gasses that may have accumulated at the base of the structure (prior to entry).

7.1.14 Public safety and security

The pump station and surrounds are to be designed to avoid hazard to the public and to resist vandalism. This would include consideration of:

• gently sloping banks around the station;
• concealed electrical cables;
• high standard of locking doors etc;
• fencing of the station site, if appropriate;
• provision of intruder alarms on cabinets or buildings;
• use of anti-graffiti paint for above ground components.

7.1.15 Operation and maintenance manuals

Draft operation and maintenance manuals for the pump station are required to be produced and presented by the developer to ACTEW at least three weeks prior to the handover date. ACTEW will examine these draft manuals and comment on their suitability within two weeks. The draft manuals are to include (but not be limited to) final wiring diagrams, a final ladder diagram, and final PLC software (on floppy disk). Final manuals are to be presented at handover.

7.2 Rising mains

Rising mains are to be designed to minimise septicity of sewage while in traverse, and to ensure ease of operation and maintenance of the main.

To minimise septicity, sizing shall be determined by minimum velocity requirements that will limit both slime growth and the detention time of the sewage in the pipe. In general, rising main velocities between l and 3 meters per second are acceptable.

To minimise potential operations and maintenance problems the smallest possible diameter pipe shall be used, with a minimum size of DN80 for carrying raw sewage and DN50 for carrying septic tank effluent. Rising mains shall be graded so as to be continuously rising. In the terminal (discharge) region the vertical alignment of the pipe should be designed to minimise the length of a partly full pipe between pumping cycles (refer to Clause 5.1.19). If such grading is not practical, automatic air valves and manually operated scour valves may be required. In such cases, proposals should be discussed with ACTEW at an early stage in the design.

Corrosion and rupture resistant pipe materials shall be used for the rising main. Rising mains shall be located outside leased land to protect lessees from the effects of possible pipe rupture.

The rising main, up to the discharge maintenance hole, is considered an integral part of the pump station. It is therefore required to be handed over at the same time as the pump station.

Issues relating to high septicity, due to long retention periods during early stages of development, shall be resolved using hydrogen sulphide control principles as set out in the document entitled Hydrogen Sulphide Control Manual — Septicity, Corrosion and Odour Control in Sewerage Systems (Reference 10.13).

Refer to Standard Drawing No. WSS 055 for a typical rising main connection to gravity sewer.

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8. Standards covering sewerage 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 ACTEW's Standards. Any queries are to be referred to the Manager, Water and Sewerage Assets.

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

8.1	Materials — DICL pipes fittings
AS 1646	Elastometric Seals for Waterworks Purposes (1992)
AS 2280	Ductile Iron Pressure Pipes and Fittings (1995)
8.2	Materials — PVC pipes
AS/NZS 1260	PVC Pipes and Fittings for Drain, Waste and Vent Applications (1996)
AS/NZS 1477	PVC Pipes and Fittings for Pressure Applications (1996)
AS/NZS 4441(Int)	Oriented PVC (OPVC) Pipes for Pressure Applications (1996)
8.3	Materials — PE pipes
AS/NZS 4130	Polyethylene (PE) Pipes, Pressure Applications (1997)
8.4	Materials — VC pipes
AS 1741	Vitrified Clay Pipes and Fittings with Flexible Joints — Sewer Quality (1991)
8.5	Materials — Steel pipes and specials
AS 1646	Elastometric Seals for Waterworks Purposes (1992)
AS 1830	Iron Castings — Grey Cast Iron (1986)
AS 3996	Metal Access Covers, Road Grates and Frames (1992)
AS 4087	Metallic Flanges for Waterworks Purposes (1996)
8.6	Materials — Concrete pipes and specials
AS 4058	Precast Concrete Pipes (Pressure and Non-pressure) (1992)
AS 4198	Precast Concrete Access Chambers for Sewerage Applications (1994)
8.7	Materials — Pipes (specials)
AS 3518	Part 1 (AS 3518.1) — Acrylonitrile Butadiene Styrene (ABS) Pipes and Fittings for Pressure Applications — Pipes (1988)
AS 3571	Glass Filament Reinforced Thermosetting Plastics Pipes (GRP) — Polyester Based — Water Supply, Sewerage and Drainage Applications (1989)
8.8	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 1657	Fixed Platforms, Walkways, Stairways and Ladders — Design, Construction and Installations (1992)
AS 2032	Code of Practice for Installation of UPVC Pipe Systems (1977)
AS 2200	Design Charts for Water Supply and Sewerage (1978)
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-Detectable Tape (1995)
AS 2700	Colour Standards for General Purposes (1996)
AS/NZS 3500	National Plumbing and Drainage Code (Part 0 to Part 4.2 inclusive)
AS 3571	Glass Filament Reinforced Thermosetting Plastics Pipes (GRP) — Polyester Based — Water Supply, Sewerage and Drainage Applications (1989)
AS 3600	Concrete Structures (1994)
AS 3725	Loads on Buried Concrete Pipes (1989)
AS 3735	Concrete Structures for Retaining Liquids (1991)
AS 3855	Suitability of Plumbing and Water Distribution Systems Products for Contact with Potable Water (1994)
AS 3972	Portland and Blended Cements (1997)
AS 4060	Loads on Buried Vitrified Clay Pipes (1992)
AS HB72	Design Vehicles and Turning Path Templates (1995)

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9. Standard drawings

Road verge drawings — drawing Nos. SEP4 — 01 to 06, chapter 4 (road verges) (Reference 10.15)

WSS 001 —	Design Symbols and Notation
WSS 002 —	Access Ladder and Staggered Step Iron Details
WSS 052 —	DN1050 Cast In-situ Maintenance Hole
WSS 053 —	DN1200 — 1500 Cast In-situ Maintenance Holes
WSS 054 —	Typical House Connections (Service Ties)
WSS 055 —	Typical Minor Neighbourhood Sewage Pump Station and Rising Main
WSS 056 —	Standard Bedding Details for Sewer Mains DN100 — DN300
WSS 057 —	Precast Concrete Maintenance Hole Components
WSS 058 —	Class B Concrete Maintenance Hole Cover and Surround
WSS 061 —	Sewer Maintenance Shaft (SMS) and Rodding Points Typical Arrangement
WSS 062 —	Standard Offsets for Simple Maintenance Hole Configurations

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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	Metropolitan Water Sewerage and Drainage Board, Sydney (1979), "Design of Separate Sewerage Systems" .
10.3	Thistlethwayte, D.K.B. (Ed.) (1972), "The Control of Sulphides in Sewerage Systems" , Butterworths, Sydney.
10.4	Boston Society of Civil Engineering (1942), "Minimum Velocities for Sewers" , Journal, Post Soc C E, Vol 29 No 4, October.
10.5	Public Works Department, NSW (1984), "Manual of Practice — Sewer Design" , Sydney.
10.6	Public Works Department, NSW (1986), "Manual of Practice — Sewage Pump Station Design" , Sydney.
10.7	Melbourne and Metropolitan Board of Works (1970), "Colombo Plan Lectures — Sewerage Design" , Melbourne.
10.8	Commonwealth Department of Works (1972), "Notes for Guidance in the Design of Hydraulic Services" .
10.9	CSIRO: Engineering and Building Section (1984), "The Invasion of Sanitary Drains by Plant Roots: Prevention and Cure" , Technical Record 503, Sydney.
10.10	Commonwealth Department of Works (1973), "Review of Sewer Standards" , ACT Region Internal Report.
10.11	Committee on Uniformity of Plumbing and Drainage Regulations in New South Wales (1987), "New South Wales Code of Practice — House Drainage" .
10.12	Totalcare document, ACT Public Works "Basic Specification — Roads, Hydraulic Services and Landscape" , Edition No 1 (July 1991) as amended (including in particular Corrigendum No 1 to Volume 1, 11 December 1992) plus the associated "Users Guide for the Basic Specification" .
10.13	Major Urban Water Authorities of Australia: Technological Standing Committee on Hydrogen Sulphide Corrosion in Sewerage Works (MMBW-1990), "Hydrogen Sulphide Control Manual — Septicity, Corrosion and Odour Control in Sewerage Systems" .
10.14	'ACT Standard and Code of Practice on Manual Handling" , Second Edition 1993.
10.15	Roads and Transport Section, ACT Department of Urban Services, "Standard Engineering Practice — Roads and Bridges" , Draft No 5, 5 November 1995.

11. List of appendices

Appendix 3-1 — Peak dry weather flow (PDWF)

Appendix 3-2 — Peak infiltration / inflow (PII)

Appendix 3-3 — Most probable peak dry weather flow (Qdmp)

Appendix 3-4A: Pipe capacities — DN150

Appendix 3-4B: Pipe capacities — DN225

Appendix 3-4C: Pipe capacities — DN300

Appendix 3-4D: Pipe capacities — DN375

Appendix 3-4E: Pipe capacities — DN450

Appendix 3-4F: Pipe capacities — DN525

Appendix 3-4G: Pipe capacities — DN600

Appendix 3-4H: Pipe capacities — DN675

Appendix 3-4I: Pipe capacities — DN750

Appendix 3-4J: Pipe capacities — DN825

Appendix 3-5 — Minimum grades and proportional hydraulic data

12. List of figures

Figure 3.1 — Peak dry weather flow (PDWF)

Figure 3.2 — Peak infiltration / inflow (PII)

Figure 3.3 — Most probable peak dry weather flow (Qdmp)

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