Research & Development
Aquatech Syphonics in association with the Civil Engineering department of the University of New South Wales have conducted various tests, the results of which can be forwarded upon request.
The initial report is in regard to the Aquatech Syphonic outlet flow rates and subsequent water levels in gutters utilizing a range of differing air baffle designs. The following is an excert from this report and describes the functions and principals of the Aquatech Syphonic Drainage System. (For Furthur information from this report, including test data & graphical analysis, please contact Aquatech Syphonics.)
Performance of Syphonic Drainage Systems (initial conclusions)
Syphonic drainage systems are a highly effective means of roof and building drainage design. The innovative technology of draining stormwater by syphonic systems have been embraced by architects, engineers, developers, and contractors due to the ability to offer significant cost savings and reliability over other alternative systems.
The basic principle of the design is to divert water from the roof surface into the pipework and a strategically positioned baffle device eliminates vortices from forming and prevents air from entering the pipework. If a system is suitably sized, the high speed of the water removes the air present in the pipes more quickly than it can enter through the outlets.
Conventional roof drainage systems collect water in a box, or eaves gutter and remove that water using freely discharging downpipes that are designed to flow commonly up to one third full under the action of gravity. The flow capacity of a conventional system is usually determined by the size of the outlets and by the depth of water above them.
The common configuration for a syphonic roof drainage system consists of numerous syphonic outlets along a length of gutter. These are connected to an underlying horizontal collector pipe that conveys water to a vertical downpipe. As the flow is acting under pressure, there is generally no need to provide a slope on the collector pipe, which itself is much smaller in diameter than would be required in a conventional gravity system. This provides distinct architectural advantages in terms of reduced space at ceiling level and often the elimination of internal downpipes. Cost savings are also achieved through the reduction in drainage infrastructure below the building floors.
A syphonic system applied to equivalent settings can have a significantly higher flow capacity because, if the pipework is enabled to flow full, the driving head becomes equal to the vertical height between the roof and the point of discharge. As below atmospheric pressure is generated within the pipes of a syphonic system, this in turn leads to water being literally sucked from the roof. When a system is operating at its design intensity, the high velocity of the water will ensure the system is self-cleansing. When rainfall is light, and flowrate off the roof surface into the gutter is small, a syphonic system will operate in unprimed mode, similar to a conventional gravity system. Priming of the system is a passive action induced purely by changing flowrate conditions.
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