These excerpts are taken directly from:
AS/NZS 3500 Plumbing and drainage
Part 4: Heated water services
1.9.2 Sanitary fixtures delivery temperature
All new heated water installations shall deliver heated water not exceeding—
(a) 45°C at the outlet of sanitary fixtures used primarily for personal hygiene purposes for the aged, the sick, children or people with disabilities in healthcare and aged care buildings, early childhood centres, primary and secondary schools and nursing homes
or similar facilities for the aged, the sick, children or people with disabilities;
(b) 50°C at the outlet of sanitary fixtures used primarily for personal hygiene purposes for all other situations.
5.4 Protection Against Damage From Leaking Water
5.4.1 Concealed water storage tanks
All water containers, cold water storage tanks, cold water storage tank-fed water heaters or storage water heaters that are installed in roof spaces, in cupboards or otherwise concealed shall be placed on safe trays complying with Clause 5.4.3. The safe trays shall be drained by safe wastes complying with Clause 5.4.4.
Notwithstanding the above requirements, mains pressure water heaters may be installed on
a safe tray without a safe waste, provided a leak protection device is fitted adjacent to the
cold water inlet and upstream of any expansion control valve.
5.4.2 Unconcealed water storage tanks
Unconcealed water storage tanks, installed inside buildings on or above a floor surface that is impervious to water and suitably drained to a trapped or untrapped floor drain or an external doorway, do not require safe trays. A mains pressure water heater with a leak protection device fitted adjacent to the cold water inlet and upstream of any expansion control valve does not require a safe waste.
All other unconcealed water storage tanks that are installed inside buildings shall be installed with safe trays complying with Clause 5.4.3 and safe wastes complying with Clause 5.4.4.
NOTE: Free outlet-type storage water heaters, not exceeding 13.5 L capacity, and instantaneous water heaters do not require safe trays.