In Australia, a box gutter is defined as "a graded channel, usually rectangular in shape, used to collect and convey rainwater from a roof to a downpipe or a drainage system" . Box gutters are an essential part of the roof drainage system in commercial construction, allowing for the efficient collection and disposal of rainwater.
The design and installation of box gutters in commercial construction in Australia are governed by several Australian standards and Building Code of Australia (BCA) requirements. Some of the relevant standards include:
- The National Construction Code (NCC) , which provides the minimum requirements for the design and construction of buildings in Australia, including the requirements for roof drainage systems.
- The Australian Standard AS 3500.3:2015, which provides the requirements for the design and installation of stormwater drainage systems, including box gutters.
BCA Requirements
The BCA requires that box gutters be designed and installed in accordance with the following requirements:
- Box gutters must be designed to collect and convey rainwater from the roof to a downpipe or drainage system .
- Box gutters must be graded to ensure that water flows freely to the downpipe or drainage system .
- Box gutters must be sized to accommodate the expected rainfall intensity and roof catchment area .
- Box gutters must be installed with a minimum fall of 1:200 to ensure that water flows freely to the downpipe or drainage system .
- Box gutters must be designed and installed to prevent water from overflowing or accumulating in the gutter .
Design Considerations
In addition to the BCA requirements, there are several design considerations that must be taken into account when designing and installing box gutters in commercial construction in Australia. These include:
- The materials used in the construction of the box gutter, including the gutter, sumps, rainhead, and downpipes .
- The size and shape of the box gutter, which must be designed to accommodate the expected rainfall intensity and roof catchment area .
- The fall and grade of the box gutter, which must be designed to ensure that water flows freely to the downpipe or drainage system .
- The connection of the box gutter to the downpipe or drainage system, which must be designed to prevent water from overflowing or accumulating in the gutter .
