Safe trays within household units

Posted: 31 May 2017

Building System Performance has been asked for clarification about the amendment to Paragraph 5.2.3 Safe trays in Acceptable Solution for Water Supplies G12/AS1, which was published on 1 January 2017, and will come into full effect on 1 June 2017.

The amendment means that if:

  • you are installing a storage water heater, and
  • you didn’t have one installed previously, and
  • G12/AS1 is your nominated means of complying with the Building Code;

then a safe tray is required with storage water heaters when installed in household units and occupancies adjoining household units.

When replacing an existing storage water heater with another storage water heater, a safe tray is not required, but it is recommended and will give additional protection to the homeowner from water damage.

Why are safe trays required?

Safe trays are required as a means to prevent water damage to household units caused by storage water heaters.

Why aren’t safe trays required for replacement storage water heaters?

Installing a new storage water heater, including attaching the pipes, valves and seismic restraint, is new building work that is required to comply with the Building Code.

However, replacing an existing storage water heater is considered an ‘alteration to an existing building’ under the Building Act. The Building Act has upgrading provisions for alterations. These provisions relate to means of escape from fire, and access and facilities for people with disabilities, and that after the alteration the building will continue to comply to at least the same extent as it did before the building work.

Where an existing storage water heater does not have a safe tray, and is replaced as an alteration to an existing building, then a safe tray is not required, as the building is only required to comply to at least the same extent as before the alteration.

Are there other places that safe trays are not required?

Safe trays are not required in buildings that are not household units, unless the adjoining occupancy is a household unit. Buildings solely used as commercial buildings such as offices or warehouses do not require safe trays.

Safe trays are not required for non-storage water heaters, such as under-bench boilers/chillers and instantaneous water heaters.

Options to consider for new or replacement storage water heaters where a safe tray is difficult to install

If a safe tray is difficult to install, in either a new or replacement situation, other options can be discussed between the plumber or building designer and the owner of the building. These can include:

  • locating the storage water heater outside
  • using instantaneous water heaters.

Acceptable Solution for Water Supplies G12/AS1 has further information.

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: