Survey-Strata Lots
2) For survey-strata lot schemes or multi-unit sites with three or more residential buildings:
Provision of reflux valves and inspection shafts for survey-strata lot schemes. Requirements for the location of any required reflux valves and inspection shafts for survey-strata lot schemes may vary according to the number of dwellings in the development. The requirements for the installation of reflux valves and inspection shafts on two lot survey-strata schemes, those with three or more individual lots and multi-unit developments, are as follows: 1) For survey-strata schemes with two individual lots:
a) Where there is only one inspection shaft at or near the point of connection to the main sewer, and either building requires additional protection against sewerage surcharge, the reflux valve must be placed adjacent to that inspection shaft.
b) Alternatively, an additional inspection shaft may be installed at or near the boundary of either lot with the reflux valve, if required, placed adjacent to the additional inspection shaft (see Diagram 1).
a) They must comply with AS/NZS 3500.2:2018, section 14, multi-unit developments. In this case there is a requirement to install an inspection shaft, overflow relief gully and open upstream vent for each building. If a reflux valve is necessary for any building in the development and one has already been installed adjacent to the inspection shaft at the connection point to the main sewer, no additional reflux valves are required (see Diagram 2).
Diagram 2
b) If a reflux valve is not provided on the inspection shaft at or near the point of connection to the main sewer, reflux valves can be installed adjacent to the inspection shafts serving individual buildings as required (see Diagram 3).
Diagram 3
The licensed plumbing contractor responsible for the installation/connection of the fixtures within each building must ensure that the necessary overflow relief gully and reflux valve requirements for those fixtures are met. Article supplied by the Building and Energy Division of DMIRS.
Diagram 1 Master Plumber | 17
