Dam Buster's amazing sumps revolutionize another critical area of roof drainage
Free flow Dam Buster Sumps are fully engineered and certified devices which don't require complex calculations to size. They also don't require the water level to back flow and rise in the box gutter before they operate in the overflow condition. Like all Dam Buster devices, they are selected based on flow rate in litres/second.
Our revolutionary design makes these sumps an absolute breeze to select and install when compared to the very complex ‘Sump / high capacity overflow’ device in AS/NZS 3500.3. Dam Buster sumps can also be safely used in lieu of the code specified Sump / side overflow devices.
Dam Buster free flow sumps come factory made in 100mm size increments to suit all sizes of box gutter between 200mm and 600mm. They can be easily fitted to virtually any box gutter, whether new or retrofit and are part of the integrated Dam Buster roof drainage system.
How They Work: If the first chamber of the Dam Buster free flow sump is overwhelmed, or if the first chamber blocks with debris, the water just crests the internal weir and flows into the second chamber where it is safely disposed of via a second (overflow) down pipe to atmosphere as required by the code. An additional overflow to atmosphere can also be fitted to the end of the second chamber if required, providing multiple redundancy.
Pick Your Size: You can find the selection tables in our Product Technical Statement which is available from Technical Downloads
Physical external product dimensions can be found HERE.
Unlike existing sumps made by all other manufacturers, box gutters discharging to a Dam Buster Sump are designed for genuine ‘free flow’ in accordance with Figure I1 of AS/NZS 3500.3 in both the normal and overflow conditions. This also means the box gutter can be designed independently of the sump i.e similar to the rainhead.
Please Contact Us for more information.
Standard free flow sump installation example
Sumps are available in Colorbond, Zincalume, stainless steel, Colorbond Ultra or any other suitable sheet metal material. They can also be easily powder coated if required.
Potential uses of these amazing devices are limited only by the imagination, but include:
They easily replace standard code sumps - Dam Buster sumps are much simpler, require no custom design or certification, perform far better and are also potentially a lot cheaper
Multiple sumps can be used along a single box gutter, including over very long distances. Extra redundancy can easily be built in along the length of the gutter by cutting down the end wall of the sump overflow chamber/s in accordance with the Dam Buster Installation Manual.
Installing the sumps back to back to double the capacity.
They provide extra versatility in roof drainage and building design. As an example, they can be installed where a rainhead cannot be used due to the presence of a window or door below; in this case both the normal and overflow downpipes can potentially also be concealed and directed internally away from the sump location.
NOTE: Requirements vary from state to state but generally a Performance Solution is required for installation certification purposes of Dam Buster free flow sump devices; Documentation to assist the development of a suitable Performance Solution can be found here at Technical Downloads
Sump with additional indicator overflow fitted
Check Out How the Dam Buster Free Flow Sump Works!
FAQs
Are Dam Buster sumps compliant?
Absolutely Yes. We've done the hard yards and all Dam Buster products achieve full conformance and compliance with the relevant NCC Performance Requirements via two methods, more details of which you can find here under Compliance.
Don't forget that "Performance Solution is also Compliance", so if a proposed installation is not (or may not be) considered Deemed to Satisfy, an appropriately prepared full Performance Solution is another fully permitted alternative pathway.
All Dam Buster products fully meet all of the roof plumbing standards and codes right across Australia including AS/NZS3500.3:2021 (and all previous versions). The method of compliance may however vary from state to state. For Victoria, the Victorian Building Authority (VBA) has specifically advised (Fact Sheet March 2023) in relation to Dam Buster products that: "The VBA does not endorse any specific plumbing products and is satisfied as long as the products are fit for the intended purpose & meet the relevant Performance Requirements of the NCC Volume Three."
All Dam Buster products 100% meet these performance requirements of the NCC Volume 3, PLUS they also meet all of the requirements for NCC in all other states and territories in Volumes 1 and 2.
Remember: fake copies of Dam Buster products don't meet any standards, are Non-Conforming Building Products under the NCC and an automatic fail for any plumbing audit. Fakes are complete junk, and if you buy them you have been ripped off, so just don't do it.
How do I calculate the size of my sump correctly?
Go to our quick design guide HERE. Follow the steps from page 3 - 13, specifically following either Method A or B to calculate your 1% AEP, then on page 6 calculate your flow rate with your catchment area, finally size appropriately with the table on page 14.
This is a simplified version of the requirements set out in AS3500.3 which has been in force nationally since 1998. These aren't just requirements for Dam Buster products, these are calculations required for ALL roof drainage design as well as roof drainage products.
Please ensure to read all of the steps and fully understand what you are required to calculate, failure to do so will likely result in a non-compliant system.