Part B1 Cold water services
Introduction to this Part
This Part sets out the requirements for the design, construction, installation, replacement, repair, alteration and maintenance of any part of a cold water service of a property that is connected to the drinking water supply. It covers from the point of connection to the points of discharge.
This part also applies to a cold water service connected to a rainwater harvesting system.
The Objective of this Part is to—
- safeguard people from illness, injury or loss (including loss of amenity) due to the failure of a cold water installation; and
- ensure that a cold water installation is suitable; and
- conserve water and energy; and
- safeguard the environment; and
- safeguard public and private infrastructure; and
- ensure that a cold water installation is designed and is capable of being maintained so that throughout its serviceable life it will continue to satisfy Objectives (a) to (e).
Sanitary fixtures, sanitary appliances and supply outlets provided with drinking water must have safe and adequate piped cold water supply.
The cold water service must be conveyed through plumbing installations in a way that minimises any adverse impact on building occupants, the Network Utility Operator's infrastructure, property and the environment.
BP1.1 Water supply
BP1.2 Design, construction and installation
A cold water service must ensure the following:
Water is provided at required flow rates and pressures for the correct functioning of fixtures and appliances.
Access for maintenance of mechanical components and operational controls.
The system, appliances and devices can be isolated for testing and maintenance.
The efficient use of drinking water.
A cold water service must avoid failure or uncontrolled discharge.
Explanatory information: Unintentional heating of cold water services
Where installed in locations subjected to extreme summer temperatures (such as the roof space of a building), cold water services have the potential to become unintentionally heated. This can pose a hazard as the cold water supply may reach temperatures in excess of 45º Celsius, increasing the potential for scalding.
To reduce the likelihood of unintentional heating of cold water services, consideration should be given to—
- avoiding long runs of pipework in locations exposed to solar heat gain; or
- applying insulation, either directly to the pipework, or by using additional ceiling insulation material between the pipework and the solar heat source.
Avoidance of unintentional heating of cold water services in known areas of extreme summer temperatures may also assist in reducing water usage through drawing off of water which has become excessively heated.
There are no Verification Methods in this Part.
B1.2 Sanitary flushing
A cistern or flushing valve used for the purpose of flushing a water closet pan must have a dual flushing mechanism that, when operated, discharges—
for a 6/3 litre cistern—
not less than 5.5 litres and not more than 6.5 litres for a full flush; and
not less than 3.0 litres and not more than 3.5 litres for a reduced flush; and
for a 4.5/3 litre cistern—
not less than 4.3 litres and not more than 4.7 litres for a full flush; and
not less than 2.8 litres and not more than 3.2 litres for a reduced flush.
The requirements of B1.2(1) do not apply to a vacuum water closet pan.
The volume of water discharged to a flush urinal must not exceed 2.5 litres for each—
single urinal stall; or
600 mm length of a continuous urinal wall, or part thereof.
Automatic or set-cycle cisterns must not be installed.
A programmed solenoid operated flushing system may be used if programmed to shut down during extended periods of non-occupancy of a building. Prior to installing this type of system further advice should be sought from the authority having jurisdiction. Where sensor control is used for urinal flushing, sensors should be located to avoid unnecessary 'nuisance' flushing triggered by pedestrian traffic.
B1.3 Maximum flow rate for cold water outlets
The outlet of a shower, basin, kitchen sink or laundry trough must have a maximum flow rate of not more than 9 litres per minute.
The requirements of B1.3 do not apply to a shower intended to provide rapid drenching of a person for emergency purposes, such as chemical removal.
B1.4 General requirements
The design, construction, installation, replacement, repair, alteration and maintenance of cold water services must be in accordance with AS/NZS 3500.1.
Explanatory information: Cross-volume considerations
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
Termite management for attachments to buildings and penetrations through a slab
Penetrations for pipework through a vapour barrier
Pipework in timber bearers and joists of solid timber or engineered wood products
Fittings, fixtures and pipework installations in steel framed construction
Penetrations through a fire-resisting wall or floor
Fixtures or fittings in a wet area
Service pipework external to the building and penetrations through roof cladding in a bushfire prone area
Pipework sound insulation
Power supply to boiling and/or chilled water storage units