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).
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.
(1) A sanitary drainage system must ensure there is adequate ventilation to avoid foul air and gases accumulating in the sanitary drainage and sewerage system.
(2) A sanitary drainage system must ensure that ventilation is provided to avoid hydraulic load imbalance such that—
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).
Determination of sanitary drainage wastewater flowrates
New for 2022
(1) Compliance with C2P1 for pipe sizing is verified for each sanitary drainage pipework section when the design flow rate is not less than—
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.
(2) For the purposes of (1)(a), for each pipework section, the design probable simultaneous wastewater flow rate must be calculated in accordance with the following:
(3) In the equation shown at (2):
= 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.
Table C2V3a Frequency factors
Fixture usage
NCC building class
Frequency factor (K)
Intermittent use e.g. dwelling, guesthouse or office
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.
NCC Title
General requirements
NCC State
SA
NCC Variation Type
Replacement
NCC SPTC Current
General requirements
NCC ID
_3cb4aefa-6eab-4d11-9386-1d6f015abc93
NCC Blurbs
(1) A sanitary drainage system must be in accordance with AS/NZS 3500.2; subject to the following—
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—
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.
(2) Discharge pipes measuring DN 50 or smaller must not be installed in a below ground sanitary drainage system, except for discharge pipes connected to floor waste gullies or vertical riser from a graded drain.
NCC Title
General requirements
NCC State
VIC
NCC Variation Type
Replacement
NCC SPTC Current
General requirements
NCC ID
_38b63336-4b6f-4126-82f5-77c20d70cf0c
NCC Blurbs
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.
Insert NSW figure (C2D4a) as follows:
NSW Figure C2D4a: Reflux valves - diagram 1
Insert NSW figure (C2D4b) as follows:
NSW Figure C2D4b: Reflux valves - diagram 2
Notes
Where a reflux valve is installed the valve remains the responsibility of the property owner.
NCC Title
General requirements
NCC State
NSW
NCC Variation Type
Replacement
NCC SPTC Current
General requirements
NCC ID
_fe0463c4-b3a1-49aa-b430-e4f6fb3222d0
(1) A sanitary drainage system must be in accordance with AS/NZS 3500.2.
TAS C2D4 General requirements2019: C2.4
Insert TAS subclause C2D4(2) in clause C2D4 as follows:
(2) For Tasmanian venting requirements see TAS C2D6.
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.
Table C2 Cross-volume considerations
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