Part B1 Cold water services
TAS B1P5 Pressure2019:BP1.2, TAS Exemption 1
The points of discharge for a cold water service must—
- a working pressure of not less than 50 kPa; and
- a static pressure within the building of not more than 500 kPa; or
- have water pressures suitable for the correct functioning of the fixture or appliance where water pressures outside of (a)(i) and (a)(ii) are required.
B1P5(a)(i) and B1P5(a)(ii) do not apply to existing low-pressure gravity only water services.
TAS B1D3 General requirements2019: TAS B1.4(1), (2) and (3)
B1D3(1) does not apply to existing low-pressure gravity only water supply systems.
TAS B1D7 Cold water storage tanks2019 TAS B101
Installation of cold-water storage tanks used to supply water to a drinking water service must comply with B1D7.
For connection of cold water tanks where reticulated supply is available refer to Sections 8 and 15 of AS/NZS 3500.1.
- AS 2070 Plastics materials for food contact use
- AS 3600 Concrete structures
- AS 3735 Concrete structures retaining liquids
- AS/NZS 2179.1 Specifications for rainwater goods, accessories and fasteners – Metal shape or sheet rainwater goods, and metal accessories and fasteners
- AS/NZS 3500.0 Plumbing and drainage
- AS/NZS 3500.1 Water services
- AS/NZ 3500.3 Stormwater drainage
- AS/NZS 4020 Testing of products in contact with drinking water
- AS/NZS 4130 Polyethylene (PE) pipes for pressure applications
- AS/NZS 4766 Polyethylene storage tanks for water and chemicals
- ABCB Procedures for the Certification of Plumbing and Drainage Products Section B Water services Tasmania
- NCC 2019 Volume Three - Plumbing Code of Australia Page 134
- The followings references are for information only— HB 230 Rainwater Tank Design and Installation Handbook and the enHealth Guidance on the use of rainwater tanks
- the nature and source of the water;
- the risk of corrosion and tank contamination;
- the nature of the environment;
- the physical and chemical characteristics of the materials and products;
- compatibility of materials and products; and
- accessibility for monitoring and maintenance.
- Manufacturer’s name, brand or trademark, and
- The Standard which the tank is manufactured to, and
- The date of manufacture.
Information on some of the above items listed in the materials above may be obtainable from the manufacturer or supplier of the product or materials.
Rainwater for drinking purposes should not be collected from recently painted roofs (until after the first few rainfalls), timber roofs preserved with chemicals, roofs coated with lead flashings, lead-based paints or tar-based coatings, or parts of roofs near flues from solid fuel heaters. Rainwater for drinking water purposes may be collected from roof types other than those identified above provided the roof and associated gutters are kept clean of leaves, animal remains, dust and other debris. Gutters must be kept clean by installing screens or leaf diverters between the roof and the water tank. The system should incorporate a ‘first flush system’ or other diversion system that will prevent the first flush of water from entering the tank.
Tanks should be regularly maintained by cleaning out accumulated sludge from the base every 2 - 3 years. For detailed advice on desludging and maintaining tanks refer to the enHealth Guide – Guidance on the use of rainwater tanks; or HB 230 Rainwater tank design and installation handbook
For ongoing maintenance of water quality one or more of the following water quality treatment methods should be adopted: Chlorinating: To commission the tank sufficient chlorine should be added to provide a free chlorine residual of 0.5 mg/L after 30 minutes. To satisfy chlorinating requirements an initial dose of 5 mg/L of chlorine may be necessary. For every kL of water in the tank, add either: 40 mL of liquid pol chlorine (sodium hypochlorite - 12.5% available chlorine); or 8 grams of granular pool chlorine (calcium hypochlorite - 65% available chlorine). To calculate the tank volume in kL for a cylindrical tank the volume in of water in kL = D x D x H x 0.785. Where D = diameter of the tank, and H = depth of water in the tank in metres. To verify this calculation, compare this volume with the maximum capacity of the tank. The chlorine residual may be tested with a swimming pool test kit or dip strips. Water after chlorinating should not be used for 24 hours to enable any harmful microorganisms to be killed off. Filtration: If filters are used in drinking water installations they are to be certified to the relevant Australian Standard under the WaterMark Certification Scheme and should be maintained by following the manufacturer’s maintenance instructions. Ultraviolet Disinfection: Filtration may be required to address water turbidity to enable adequate UV disinfection. Ultraviolet treatment is affected by the levels of turbidity, organic content from suspended solids, pH, hardness and UV transmissivity of the water. The intensity of the UV light and the build-up of suspended solids on the quartz tube affect the disinfection performance. Regular monitoring of the quartz tubes is critical. Lamps also need to be replaced regularly in accordance with the manufacturer’s instructions.