Master Plumbers June FAQ: Do you know the answers?

Question: Since the release of the 2022 National Construction Code (NCC) Volume 3 Plumbing Code of Australia was released, is there a requirement for temperature-control provisions on a change over hot-water service (installation of a tempering valve)?

Answer: We can confirm that Victoria does have an exemption in the current PCA 2022 version. The Victorian exemption states the following clause B2D5(b) does not apply to the replacement of a water heater unit in the same location where the original installation did not require a temperature control valve.

Continuing the topic of delivery temperatures... It is important to know the class of building you are working on. If you are performing plumbing works on an accessible facility in a Class 1 building, it does not automatically need to be limited to 45 degrees or a TMV. However, in the PCA it does state, Consideration should be given to the intended occupants of a building when commissioning the heated water delivery temperature. For example, if the occupants of a Class 1 building are older adults or young children, a lower temperature than specified in B2D5(b) should be considered.

Generally speaking though, the building class is what triggers the requirements. In the NCC Volume 3, clause B2D5 outlines the requirements for maximum delivery temperature of heated water and B2D6 outlines what devices can be used, such as TMV, tempering valve, temperature limited water heater, etc.

Piping material limitations: we have seen a spike in enquiries regarding the use of different piping materials for gas installations.

It is important to distinguish the material you are going to be using and cross check it against Table 4.2 in the AS/NZS 5601.1 2022 gas standard. In the limiting conditions section, there is a difference between not permitted above ground and not permitted above ground external to a building.

The discharge of a TPR drain line, is still causing some confusion. The requirements are outlined in AS/NZS 3500.4 2022, Clause 5.11.3.

(d) The point of discharge from each drain line shall be located so that the release of team or hot water does not cause a nuisance, is readily discernible and incurs no risk of damage to the building nor injury to persons.

(e) Where a drain line terminates outside a building, the end of the line shall be:

I. not lower than 75mm or higher than 300mm above an overflow relief gully or disconnector gully;

II. not lower than 75mm or higher than 300mm above a gravel pit not less than 100mm in diameter;

III. over a tundish in accordance with Item (h) below; or

IV. not lower than 200mm or higher than 300mm above an unpaved surface.

Note: Where discharges from valves may adversely affect slabs and footings of buildings, the drain lines should discharge away from the building. Further guidance is provided in the NCC.

(g) Where a water heater is externally located, the drain line from the relief valve shall be terminated so as to discharge water away from the operator during operation of the valve.

Please note: The information above is based on the Australian standards. Please check with your local regulator and authorities for variations.

Picture credit: McCarthy Plumbing Group