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Part C2 Sanitary drainage systemsPart C2 Sanitary drainage systems
Introduction to this Part
This Part sets out the requirements for any part of a sanitary drainage system of a property including from sanitary fixtures, appliances and sanitary plumbing systems from the point of connection to an approved disposal system.
Objectives
C2O1
Objective
2019: CO2
C2O1
Objective
2019: CO2
The Objective of this Part is to—
- safeguard people from illness, injury or loss (including loss of amenity) due to the failure of a sanitary drainage installation; and
- ensure that a sanitary drainage installation is suitable; and
- conserve water and energy; and
- safeguard the environment; and
- safeguard public and private infrastructure; and
- safeguard people from illness caused by the discharge of swimming pool waste water; and
- protect other property from damage caused by the discharge of swimming pool waste water; and
- ensure that a sanitary drainage installation is designed and is capable of being maintained so that throughout its serviceable life it will continue to satisfy Objectives (a) to (g).
Functional Statements
C2F1
Disposal system
2019: CF2.1
C2F1
Disposal system
2019: CF2.1
Sanitary fixtures and sanitary appliances must be provided with an adequate disposal system that does not impact adversely on occupants of the premises, property, the environment or the Network Utility Operator’s infrastructure.
C2F2
Swimming pool wastewater disposal
2019: CF2.2
C2F2
Swimming pool wastewater disposal
2019: CF2.2
Adequate means for the disposal of swimming pool water and drainage is to be provided for each swimming pool.
Performance Requirements
C2P1
Disposal
2019: CP2.1
C2P1
Disposal
2019: CP2.1
A sanitary drainage system must ensure sewage is transferred from a sanitary plumbing system to an approved disposal system.
C2P2
Swimming pool drainage
2019: CP2.2
C2P2
Swimming pool drainage
2019: CP2.2
Swimming pool drainage
A swimming pool must have adequate means of draining the pool in a manner that will not—
- cause illness to people; or
- affect other property.
C2P3
Access
2019: CP2.1
C2P3
Access
2019: CP2.1
C2P4
Ventilation
2019: CP2.1
C2P4
Ventilation
2019: CP2.1
- there is less than a 1% likelihood during the annual peak hour that when any fixture discharges, air pressure at any trap seal exceeds ±375 Pa difference from atmospheric pressure; or
- an equivalent level of safety to human health is achieved as a system complying to (a).
C2P5
Contamination
2019:CP2.1
C2P5
Contamination
2019:CP2.1
C2P6
Uncontrolled discharge
2019: CP2.1
C2P6
Uncontrolled discharge
2019: CP2.1
A sanitary drainage system must avoid blockage and uncontrolled discharge.
C2P7
Damage
2019: CP2.1
C2P7
Damage
2019: CP2.1
Notes
There are no Deemed-to-Satisfy Provisions for sanitary drainage systems to address ground movement.
Where a point of connection to a Network Utility Operator's sewerage system is not available, an on-site wastewater management system must be designed, installed and maintained in accordance with the requirements and agreement of the relevant authority having jurisdiction.
No point of connection
Verification Methods
C2V1
Velocity and liquid-to-air ratio
2019: CV2.1
C2V1
Velocity and liquid-to-air ratio
2019: CV2.1
C2V2
Pressure testing
2019: CV2.2
C2V2
Pressure testing
2019: CV2.2
C2V3
Determination of sanitary drainage wastewater flowrates
New for 2022
C2V3
Determination of sanitary drainage wastewater flowrates
New for 2022
- the probable simultaneous wastewater flow rate calculated in accordance with (2); or
- the Discharge Unit (DU) value of the highest fixture connected upstream of the pipework section as given by Table C2V3b, in litres per second, whichever is greater.
- = the probable simultaneous wastewater flowrate for that pipework section (l/s).
- = the sum of any other wastewater flowrates such as pumped discharges (l/s).
- = the frequency factor given in Table C2V3a (dimensionless).
- = the sum of the discharge units as given in Table C2V3b connected upstream of that pipework section (dimensionless).
Explanatory information
System types referred to in Table C2V3b are as follows:
- System 1 - A sanitary drainage system where branch discharge pipes are designed with a filling degree of 50%.
- System 2 - A sanitary drainage system where branch discharge pipes are designed with a filling degree of 70%.
- System 3 - A sanitary drainage system where branch discharge pipes are designed with a filling degree of 100%.
- Systems 1 and 2 are similar to the fully vented modified system and System 3 is similar to the single stack system, as detailed in AS/NZS 3500.2.
- Filling degree is defined as the ratio between the height of fluid in a pipe (h) and the diameter of the pipe (D), or h/D.
Fixture usage | NCC building class | Frequency factor (K) |
---|---|---|
Intermittent use e.g. dwelling, guesthouse or office | Class 1, Class 2, Class 3 or Class 4 | 0.5 |
Frequent use e.g. hospital, restaurant or hotel | Class 5, Class 6, Class 7, Class 8, Class 9a or Class 9c | 0.7 |
Congested use e.g. open to the general public, school | Class 9b | 1.0 |
Special use e.g. laboratory | Not applicable | 1.2 |
Fixture | System 1 - Discharge Units (DU) | System 2 - Discharge Units (DU) | System 3 - Discharge Units (DU) |
---|---|---|---|
Basin | 0.5 | 0.3 | 0.3 |
Shower | 0.6 | 0.4 | 0.4 |
Urinal | 0.8 | 0.5 | 0.4 |
Bath | 0.8 | 0.6 | 1.3 |
Kitchen sink | 0.8 | 0.6 | 1.3 |
Water closet | 2.0 | 1.8 | 1.2 |
Washing machine - Up to 6 kg | 0.8 | 0.6 | 0.6 |
Domestic dishwasher | 0.8 | 0.6 | 0.2 |
Deemed-to-Satisfy Provisions
C2D1
Deemed-to-Satisfy Provisions
2019: C2.1
C2D1
Deemed-to-Satisfy Provisions
2019: C2.1
C2D2
Invert levels
2019: C2.2
C2D2
Invert levels
2019: C2.2
The invert level of a trap or gully weir must be a minimum of 10 mm higher than the soffit of the pipe to which it connects.
C2D3
Swimming pool drainage
2019: C2.3
C2D3
Swimming pool drainage
2019: C2.3
Pumped discharge from a swimming pool must connect to the sanitary drainage system in accordance with AS/NZS 3500.2.
C2D4
General requirements
2019: C2.4
C2D4
General requirements
2019: C2.4
A sanitary drainage system must be in accordance with AS/NZS 3500.2 with the following variations:
- After AS/NZS 3500.2 clause 4.7.1(h), insert clause 4.7.1(i) as follows: Inspection openings indicated in 4.7.1(b), (d) (e) and (f) shall be raised to finished surface level. All other inspection openings need not be raised provided they are not below paved, concreted or similar finished surfaces.
- Substitute AS/NZS 3500.2 clause 2.3(a) as follows: Bends in pipes shall have a throat radius complying with Table 5.6 and Figure B6 of AS/NZS 1260 (2017) and shall be free from wrinkling and flattening.
- After AS/NZS 3500.2 clause 12.7(g), insert clause 12.7(h) as follows: Buried pumped discharge pipes and rising mains shall be placed in close-fitting durable sleeving or continually spirally wrapped. The sleeving or spiral wrapping shall be identified for the full length with the following statement: "sewer rising main" or "pumped discharge pipe" in accordance with AS 1345.
- After AS/NZS 3500.2 clause 12.7(h), insert clause 12.7(i) as follows: Above ground pumped discharge pipes and rising mains shall be permanently identified with the following statement: "sewer rising main" or "pumped discharge pipe" in accordance with AS 1345. The statement shall be installed in a visible position running longitudinally, at no more than 3 metre intervals.
- After AS/NZS 3500.2 clause 13.27.2, insert clause 13.28 as follows: All trade waste pre-treatment equipment shall connect to the sewerage system via a disconnector gully.
General requirements
- insert Clause 4.4.2.1(e): (e) Where an inspection shaft or boundary trap riser in a below ground sanitary drainage system is located clear of a building and is not likely to be damaged by vehicular traffic, a light cover must be installed in accordance with clause 4.4.2.1(a) and clause 4.4.2.1(c)(ii) and (iii).
- insert Clause 4.6.2(d): (d) Have risers installed vertically with no offsets.
- clause 5.3(c) of AS/NZS 3500.2 is varied so that concrete support used to support drains must be provided to support all bends greater than DN 65 to vertical risers.
- replace Clause 5.4.2(d) with: Free running sand, excavated from the trench, capable of passing through a 2 mm mesh sieve, which does not contain clay, organic or other deleterious materials.
- Insert Clause 15.1(b) as follows: Testing of a sanitary drainage installation. If installed at a property provided with non-drinking water by the Network Utility Operator, testing of a sanitary drainage installation may be carried out in accordance with—
- a water test using non-drinking water provided by the Network Utility Operator in accordance with clause 15.2; or
- an air test in accordance with clause 15.3; or
- vacuum test in accordance with clause 15.4; or
- in cases other than in (a), testing may be carried out by way of—
- an air test in accordance with clause 15.3; or
- a vacuum test in accordance with clause 15.4.
General requirements
A sanitary drainage system must be in accordance with AS/NZS 3500.2 with the following variations:
- For clause 4.3.1 insert (i) as follows: Must not have DN40 or DN50 traps installed.
- For clause 4.4.1 insert the following as the second paragraph: Boundary trap or inspection shafts cannot terminate within areas of buildings as defined in the NCC as a habitable room. See NCC “Definitions” and delete ‘but’ from (a) and replace with ‘,” and delete ‘excludes’ from (b).
- After clause 4.5.2(b) insert (c) as follows: Soil and waste stacks shall not discharge through a reflux valve except where a reflux valve is installed at the connection to the sewer required with surcharging sewers.
- Substitute clause 4.5.3 as follows: Where a surcharge is likely to occur and a reflux valve is to be installed, it shall be located in accordance with (i) and (ii) as follows:
- Where the drain has an inspection shaft or boundary trap, the reflux valve shall be located immediately downstream from and adjacent to the outlet of the shaft or trap.
- The invert of the outlet of the reflux valve shall be installed a minimum of 80 mm higher than the invert of the Network Utility Operator’s system it is connected to. See NSW Figures C2D4a and C2D4b.
- After clause 4.7.1(h) insert (i) as follows: At each branch off a main line internal of the building connecting one or more water closets or slop hoppers. In these cases. inspection openings must be raised to finished surface level in an accessible position and sealed with an airtight cover. If access to the under floor area is more than 600 mm above the inspection opening, the riser may be omitted.
- After clause 12.7(g) insert (h) as follows: Sewage management facilities shall be accredited by NSW Health and comply with local government requirements. Before a connection is made to pump raw sewage or effluent from a septic tank or holding well to the Network Utility Operator’s sewer, an application must be made to that Network Utility Operator. Applicants must meet the pump to sewer requirements and conditions for all connections to the sewer. A marker tape must be laid along the top of all pump discharge or rising mains pipes at intervals of not more than 3 m.
Notes
Where a reflux valve is installed the valve remains the responsibility of the property owner.
General requirements
TAS C2D4 General requirements2019: C2.4
C2D5
Bushfire prone areas
New for 2022
C2D5
Bushfire prone areas
New for 2022
A sanitary drainage system in a designated bushfire prone area must be in accordance with AS 3959.
- a secondary vent within 10 metres of the on-site wastewater management system; or
- where (a) cannot be achieved, a low level (ground) vent at the sanitary drainage point of connection.
- are located at the point of connection to an on-site wastewater management system; and
- terminate at or above finished surface level.
Explanatory information
See TAS Figure C2D6 Alternative venting arrangements
Venting requirements
Explanatory information: Cross-volume considerations
NCC Volumes One and Two deal with a number of areas of on-site construction which are relevant to a sanitary drainage system. These include, but are not limited to, those listed in Table C2.
Item | NCC Volume One Class 2 to 9 buildings | NCC Volume Two Class 1 and 10 buildings |
---|---|---|
Excavations for pipework adjacent to a building and footings | B1 Structural provisions | H1 Structure |
Termite management for attachments to buildings and penetrations through a slab | B1 Structural provisions | H1 Structure |
Penetrations for pipework through a vapour barrier | B1 Structural provisions | H1 Structure |
Pipework in timber bearers and joists of solid timber or engineered wood products | B1 Structural provisions | H1 Structure |
Fittings, fixtures and pipework installations in steel framed construction | B1 Structural provisions | H1 Structure |
Penetrations through a fire-resisting wall or floor | C1 Fire resistance Performance Requirements and C4 Protection of openings | H3 Fire safety |