Vortex Breaker Strainers for Roof Drains - Getting Water Off Your Roof
The frequency of torrential rains and microbursts in much of the United States has increased dramatically since 1958, according to the U.S. National Climate Assessment’s “Climate Change Impacts in the United States”1 which puts large amounts of rain on the roof in very short periods of time. The impact of all this heavy rainfall on roofs can, has been and will continue to be disastrous, especially when roof drainage systems fail.
What happens is this: as water proceeds down the drain, a vortex will form by traveling around the inside of the pipe rather than straight down the pipe. This vortex slows the flow rate, allowing water to “back up” or pond on the roof. If the flow rate is too low, more water remains on the roof, adding five pounds per square foot per inch of weight to the roof and potentially over taxing the building’s structural live load capacity. To visualize, a 20 X 20 foot (400 square feet) area with 1” head of water weighs 2,000 lbs.
What can be done to address this concern without adding more drain lines or converting existing lines larger costing several thousands of dollars and inconvenience?
CentiMark, working with one of our vendors: OMG, uses their Vortex Breaker Strainer. It’s a new technology designed as a retrofit upgrade option for installed OMG Hercules Drains and features three fins built into the strainer designed to break the vortex and help water flow straight down for better rooftop performance. When upgraded with the Vortex Breaker Strainer Dome, Hercules Drains offer up to 2.5 times greater water flow than the original Hercules Drains without a vortex breaker. This means water is draining from the roof faster and taking weight with it.
It’s a great tool for rooftop drains, especially in areas with heavy rains.
This blog was written in cooperation with Dan Genovese, Product Manager, OMG Roofing Products.