NCC 2019 Volume Three
Section B Water services

Section B Water services

Part B1 Cold water services

Delete Introduction to this Part and insert Tas Introduction to this Part as follows:

Tas 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, from the point of connection to the points of discharge. For the avoidance of doubt, the point of connection includes any tanks used for the collection, storage and supply of drinking water.

Delete B1.4(1) and insert Tas B1.4(1), (2) and (3) as follows:

Tas B1.4 General Requirements

(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 Part B101.

(3)

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

Tas Part B101 Cold water storage tanks

Tas Introduction to this Part

This Part is an addition to the Deemed-to-Satisfy Provisions of Part B1. It sets out the requirements for pre-fabricated and constructed on-site cold-water storage tanks used in a drinking water supply system.

Tas B101.1 Application

(1)

This Part 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 this Part. For connection of cold water tanks where reticulated supply is available refer to Sections 8 and 16 of AS/NZS 3500.1.

Tas B101.2 Cold water storage tanks

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

3600 Concrete structures

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

3500 Plumbing and drainage

3500.1 Water services

3500.3 Stormwater drainage

4020 Testing of products in contact with drinking water

4130 Polyethylene (PE) pipes for pressure applications

4766 Polyethylene storage tanks for water and chemicals

ABCB

Procedures for the Certification of Plumbing and Drainage Products

The followings references are for information only—

HB 230 Rainwater Tank Design and Installation Handbook

enHealth Guidance on the use of rainwater tanks

Tas B101.3 Materials

(1)

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—

(a)

the nature and source of the water;

(b)

the risk of corrosion and tank contamination;

(c)

the nature of the environment;

(d)

the physical and chemical characteristics of the materials and products;

(e)

compatibility of materials and products; and

(f)

accessibility for monitoring and maintenance.

Explanatory information:

Explanatory information:

Information on some of the above items may be obtainable from the manufacturer or supplier of the product or materials.

(2)

Plastics

Plastic tanks must comply with AS/NZS 4766.

(3)

Waterstops, joint fillers and sealants

Sealants used in the manufacture of tanks must be certified under the WaterMark Certification Scheme to AS/NZS 4020.

(4)

Solders

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.

(5)

Stainless steel

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

(6)

Dezincification resistant (DR) copper alloys

Where dezincification resistant copper alloys are specified, they must comply with AS 2345.

(7)

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.

(8)

Concrete tanks

Concrete tanks must comply with AS 3735 or AS 3600.

(9)

Tank linings

Tank linings must comply with AS/NZS 4020.

Tas B101.4 Marking of pre-fabricated tanks

(1)

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—

(a)

Manufacturer's name, brand or trademark.

(b)

The Standard which the tank is manufactured to.

(c)

The date of manufacture.

Tas B101.5 Sludge valves

(1)

A sludge valve must be fitted when the capacity of the tank exceeds 500 L. The minimum size of the valve must be not less than half the outlet pipe size nor less than DN 40.

Tas B101.6 Collection

Explanatory information:

Explanatory information:

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.

Tas B101.7 Openings in tanks

(1)

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.

Tas B101.8 Maintenance

Explanatory information:

Explanatory information:

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.

Tas B101.9 Commissioning

(1)

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).

Explanatory information:

Explanatory information:

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.

Tas B101.10 Warranty

(1)

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."

Part B2 Heated water services

Delete B2.2(1)(a) and (d) and insert Tas B2.2(1)(a) and (d) as follows—

Tas B2.2 Water heater in a heated water supply system

(a)

a water heater in a heated water supply system must be—

(i)

a solar water heater complying with (b); or

(ii)

a heat pump water heater complying with (b); or

(iii)

a gas water heater complying with (c); or

(iv)

an electric resistance water heater complying with AS/NZS 3500.4; or

(v)

a wood-fired thermosiphon water heater or direct-fired water heater complying with AS/NZS 3500.4.

(d)

* * * * *

Tas B2.5 Maximum delivery temperature

Delete Application 1 and insert Tas Application 1 and Tas Exemption 1 as follows:

Tas Application 1:

Tas Application 1:

B2.5 applies to new and replacement heated water installations for personal hygiene purposes.

Tas Exemption 1:

Tas Exemption 1:

B2.5 does not apply to the replacement of a single heated water storage unit within a range or bank of heaters.

Tas B2.6 Temperature control devices

Delete B2.6(2)(d) and insert Tas B2.6(2)(d) as follows:

(d)

temperature limited water heater limited to 50° C in accordance with AS 3498.

Delete Application 1 and insert Tas Application 1 and Tas Exemption 1 as follows:

Tas Application 1:

Tas Application 1:

B2.6 applies to new and replacement heated water installations.

Tas Exemption 1:

Tas Exemption 1:

B2.6 does not apply to the replacement of a single heated water storage unit within a range or bank of heaters.

Part B4 Fire-fighting water services

After BP4.1 insert Tas BV4.1 as follows:

Verification Methods

Tas BV4.1

(1)

Verification of fire-fighting water service performance shall be conducted by a qualified third party certifier (as determined by the Tasmanian Director of Building Control) and/or the fire-fighting authority having jurisdiction.

Part B6 Rainwater harvesting and use

Tas B6.2 Collection of rainwater

After B6.2(1) insert Tas B6.2(2) as follows:

(2)

A rainwater harvesting system for Class 1 and 10 Buildings satisfies B6.1 if it is installed in accordance with the requirements within the Tasmanian Building Act — Directors Guidelines — Charged Downpipes to Rainwater Tanks of Class 1 and 10 Buildings for Drinking Water Purposes document.