Part B1 Cold water services

NCC 2022 Volume Three - Plumbing Code of Australia

TAS B1P5 Pressure2019:BP1.2, TAS Exemption 1

Delete clause B1P5 and insert TAS B1P5 as follows:

The points of discharge for a cold water service must—

have—
1. a working pressure of not less than 50 kPa; and
2. 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.

Exemptions

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)

Delete clause B1D3 and insert TAS B1D3 as follows:

(1) The design, construction, installation, repair, alteration, additions, maintenance and commissioning of cold water services must be in accordance with AS/NZS 3500.1.

(2) Cold water tanks forming part of a drinking water supply must comply with TAS B1D7.

(3) Backflow prevention for boundary containment must comply with the Network Utility Operator Boundary Backflow Containment Selection Requirements.

Exemptions

B1D3(1) does not apply to existing low-pressure gravity only water supply systems.

TAS B1D7 Cold water storage tanks2019 TAS B101

Insert TAS clause B1D7 in clause B1D7 as follows:

(1) B1D7 applies to tanks — including rainwater tanks — connected to the roof plumbing system, or a tank supplied from a nearby stream, bore or well used in drinking water services, or a drinking water supply in reticulated or non-reticulated areas.

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.

(2) Cold water storage tanks and their installation must comply with the relevant requirements of the following documents—

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
1. 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

(3) Materials and products in contact with water in a drinking water supply must comply with AS/NZS 4020. Linings and coatings must comply with AS/NZS 4020 at a surface area to volume ratio not greater than that specified in the conditions of use. Materials and products used in manufacture of tanks must be selected to ensure fitness for their intended purpose. Tanks must be selected from the relevant Standards listed in this Part. Factors to be taken into account include — but are not limited to—

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.

(4) Plastic tanks must comply with AS/NZS 4766

(5) Waterstops, joint fillers and sealants used in the manufacture of tanks must be certified under the WaterMark Certification Scheme to AS/NZS 4020.

(6) Solders used in the manufacture of tanks must be certified under the WaterMark Certification Scheme to AS/NZS 4020. Soft solder must comply with AS 1834.1 and be lead-free for roof drainage components used for the conveyance of drinking water.

(7) Stainless steel sheet must be manufactured from alloy 304 or 316 complying with ASTM A240/A240M.

(8) Dezincification resistant (DR) copper alloys Where dezincification resistant copper alloys are specified, they must comply with AS 2345.

(9) Steel sheet Hot-dipped zinc-coated or aluminium/zinc-coated sheet steel must comply with AS 1397 and have an internal lining or coating certified to AS/NZS 4020.

(10) Concrete tanks must comply with AS 3735 or AS 3600.

(11) Tank linings must comply with AS/NZS 4020.

(12) In addition to the marking requirements set out in clause 8.9 of AS/NZS 3500.1 all tanks must be permanently marked with the following—

Manufacturer’s name, brand or trademark, and
The Standard which the tank is manufactured to, and
The date of manufacture.

(13) A sludge valve must be fitted when the capacity of the tank exceeds 500 Litres. The minimum size of the valve must be not less than half the outlet pipe size and not less than DN 40.

(14) All openings to tanks must be sealed so that insects, small animals, birds and sunlight cannot enter tanks, in order to minimise the growth of algae and to prevent unauthorised access.

(15) Before using the water from a tank for the first time the tank must be cleaned and disinfected (See Appendix I of AS/NZS 3500.1).

(16) The manufacturer’s warranty must contain the following statement: “This tank has been manufactured for the storage of drinking water and all materials used are suitable for contact with drinking water.”

Explanatory information

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.