Free flow Dam Buster sumps revolutionize another critical area of roof drainage

Free flow sumps are absolutely unique in roof drainage, simply because they don't require the water level to rise in the box gutter before they operate in the overflow condition.  In fact they operate hydraulically in exactly the same way as the revolutionary Dam Buster rainhead.  

This makes them much easier to design and install than the code specified ‘Sump / high capacity overflow’ to AS/NZS 3500.3-2018. They can also be used in lieu of the code specified Sump / side overflow in many cases.  

If the first chamber of the Dam Buster free flow sump is overwhelmed, or if the chamber blocks with debris, the water just crests the weir and flows into the second chamber where it is safely disposed of via a second down pipe to atmosphere.

Like Dam Buster rainheads, Dam Buster sumps are all ‘pre-designed’.  The appropriate size is simply selected from a table of maximum allowable flow rates for sump and downpipe size combinations, based on the design flow rate in litres per second. 

Box gutters discharging to a Dam Buster Sump are simply designed for ‘free flow’ in accordance with Figure I1 of AS/NZS 3500.3-2018.  

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.  

At this stage all models are in Zincalume, but quality powder coating is available.

Potential uses of these amazing devices are limited only by the imagination, but include:

  • They easily replace standard code sumps - and are potentially a lot cheaper
  • Multiple sumps can be used along a single box gutter, including over very long distances
  • They can be used to completely replace external rain heads, giving a clutter free architectural design - a big bonus for building Architects and Designers

How the Dam Buster Free Flow Sump Works - Watch Video


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