Plumbing Connection Summer 2017

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caused the loss and claims are paid.
“More and more insurers are using
specialist assessors who will recognise
non-compliant installations and
defects and deny the claims,” says
David. “The hapless consumer who has
recently purchased their dream home
has no idea about rainheads or non-
compliance. Their property floods and
suddenly the insurance company tells
them the roof plumbing installation was
not compliant and their claim will be
denied. As insurers tighten the screws,
this is potentially the next ‘flood’ to
appear in this area of denied claims and
unhappy home owners.”
“The Dam Buster Rainhead patented
design has put together years of
hydraulic experience and mixed it with
some truly amazing manufacturing
techniques to make the seemingly
problematic rainhead and wrap it in the
skin of another rainhead to deliver the
“box in a box” Dam Buster Rainhead
that is fully compliant,” says Peter.
Quality is important to us, we pride ourselves on supplying reliable
and sustainably engineered water solution products. We successfully
upgraded our ball valve threads to conform to the new Australian
Standards 3688-2016. Our y-strainers have stainless steel 316 internals
for extended life and performance. Also the butterfly valves are
manufactured from ductile iron, FBE coated and splined shafts for long
term reliability. Install Zurn valves to keep your devices operating at peak
performance.
Contact the experts at Zurn Australia for our full range of ball valves,
y-strainers and butterfly valves.
WATER CONTROL | DRAINAGE | FLUSHING SYSTEMS | STAINLESS STEEL | TAPWARE | GENERAL LUTIONS
1300 00 ZURN
Engineered for a
better tomorrow
Ball Valves - FxF & MxF
Y-Strainers - Brass &
FBE Coated
Lugged &Wafer
Butterfly Valves
Lugged &Wafer
Butterfly Valve w/
gear operator
CALCULATING RAINHEAD SIZING
The team at Dam Buster have simplified
the zoning of rainfall intensity listed in AS/
NZS 3500.3, Appendix E, into five categories
(listed as Average Recurrence Interval – ARI).
For regional areas, consult the charts in the
Standard.
For example, in Sydney, the rainfall
intensity is up to 270mm for a 1:100 year ARI.
It is necessary to size the roof stormwater
catchment area (which should include
exposed sections of walls that may drain
into the catchment area). This must be done
to size the box gutter in accordance with
Australian Standards (as per HB 114 1998) to
give the minimum width and depth of the box
gutter required.
The Dam Buster Design Guide will give
the appropriate size rainhead to suit the
width and depth of the box gutter and the
catchment area (in sqm) based on the rainfall
intensity for the location.
With these numbers established, the
‘Design Guide for Dam Buster Rainheads’ will
also specify the acceptable range of downpipe
sizes (and shapes) that can then be cut into
the base of the Dam Buster rainhead.
A correctly sized and fitted Dam Buster
rainhead has been certified (Dr R J Keller &
Associates, Civil Engineering Hydraulics) to meet
the primary hydraulic requirement of AS3500.3
“Plumbing and drainage Part 3: Stormwater
drainage” for rainhead performance:
“3.7.5.1 Hydraulic capacity - The hydraulic
capacity of an overflow device shall be not less
than the design flow for the associated gutter
outlet. Overflow devices shall discharge to the
atmosphere.”
The Dam Buster rainhead is therefore not
only compliant with AS/NZS 3500.3 but also
compliant with the NCC as it meets or exceeds
the Deemed-to-Satisfy requirements and
meets the overall performance requirement
of the NCC Volume 3 2015 Plumbing Code of
Australia Section D I Clause DP1.1, DP1.2 and
DP1.4.
MAX RAINFALL
INTENSITY (MM) LOCATION
190 Melbourne, Adelaide, Hobart
220 Canberra, Perth
270 Sydney
330 Brisbane
390 Darwin, Cairns