VIC Part E3 Stormwater - Roof drainage systems

The Objective of this Part is to—

1. safeguard people from illness, injury or loss (including loss of amenity) due to the failure of a roof drainage installation; and
2. ensure that a roof drainage installation is adequate; and
3. conserve water and energy; and
4. safeguard the environment; and
5. safeguard public and private infrastructure; and
6. ensure that a roof drainage installation is designed and is capable of being maintained so that throughout its serviceable life it will continue to satisfy Objectives (a) to (e).

Buildings are to be provided with a roof drainage installation constructed to provide protection for people, property and the environment from the adverse effects of stormwater.

A roof drainage system must dispose of stormwater flows from rainfall events having an average recurrence interval appropriate to:

1. The importance of the building.
2. The severity of potential damage to property, loss of amenity, illness or injury that would result from the failure of the system.

A roof drainage system must provide an overflow device to transfer stormwater flows generated by extreme rainfall events.

All internal roof drainage components must be watertight.

(1) A roof drainage system must ensure the following—

1. Stormwater is transferred to a point of connection.
2. Access for maintenance and clearing blockages.

(2) A roof drainage installation must avoid the following—

1. Loss of amenity due to blockages and uncontrolled discharge.
2. Foul air and gases accumulating in the roof drainage system.
3. Loss to buildings and property amenity due to blockages and uncontrolled discharge.

Performance Requirements E3P1 to E3P4 are satisfied by complying with E3D2.

The design, construction, installation, replacement, repair, alteration and maintenance of a roof drainage system must be in accordance with AS/NZS 3500.3 and SA HB 39, subject to following:

1. Insert Clause 4.9.6.3 Fastening in AS/NZS 3500.3 as follows: Dowpipes to be securely fastened to walls and structures so as to withstand movement due to thermal expansion or weight due to a partial or total blockage, and
2. Where there are any conflicts between AS/NZS 3500.3 and SA HB 39, AS/NZS 3500.3 prevails.