Physicists Designed Splash-Free Urinal That Ensures the Pee Stream Hits Where It Is Aimed

Men can expect to have cleaner pants and shoes if they use the new splash-free urinal designed by scientists at the University of Waterloo. A bonus feature is that it is quite an aesthetically appealing design that gives the restroom a touch of class.

Waterloo's Zhao Pan told New Scientist that the idea of the splash-free urinal originated from men having to wear speckled pants or shoes after urinating. Naturally, nobody likes to pee everywhere so they decided to create a urinal where splatter is extremely unlikely. Their findings were presented during the American Physical Society (APS) meeting on fluid dynamics in Indianapolis.

Nauti-loo, Other Splash-Free Urinals

Waterloo scientists dubbed their design the "Nauti-loo," which features a tall, slender porcelain structure with curves similar to the nautilus shell that inspired its name. But it is not the first time that scientists have attempted to address the splashing issue as many designs in the past have also relied on physics to resolve it.

According to ARS Technica, Pan was a former graduate student of mechanical engineer Tadd Truscott who founded the so-called "Splash Lab" at Utah State University. They offer some tips on how men could avoid smearing their pants while peeing in restrooms.

A 2015 article in Gizmodo reports that sitting on the toilet is the best way to go because there is less distance for the pee to cover on its journey to the bowl. But for standing position, scientists advised standing as close to the urinal as possible to direct the pee stream to the back of the urinal.

Another optimal design is by Randy Hurd, who presented his design at the 2015 APS fluid dynamics meeting. It has three basic designs: one employs absorbent cloth to avoid splashing, and another uses a honeycomb structure droplets pass through and avoid the splash.

Meanwhile, the third design is inspired by a type of super-absorbent moss Syntrichia caninervis, which thrives in very dry climates making it perfect for collecting and strong water. They found that the human-made VantaBlack material mimics the absorbent properties of the moss that when used in the urinal blocked droplets of pee from escaping.

But the problem of pee splashing is not exclusive to men as even women suffer from spillage too. In 2018, Splash Lab found that the design of Orchid, which is a funnel-shaped attachment for urine cups, could reduce spillage. The research led to devices that allowed women to pee standing up.

Copying How Dogs Urinate

As New Scientist reported, Pan and his colleagues used a computer model that reproduced previous observations of how dogs urinate. Dogs instinctively know that lifting their leg will get them closer to an angle between the urine stream and a vertical surface with minimum splashback.

Researchers directed a jet of water to test urinals, testing two experimental designs against standard commercially available designs and one urinal design featured in Marcel Duchamp's "La Fontaine" artwork.

The speed of the jets vary in different experiments and they wiped the splatter with paper towels. They then weighed the wet paper towels and compared them to a dry paper towel to know how much water had to be absorbed to clean up the mess. The team determined that for an average human, the splash-reducing angle for urination is about 30 degrees.

They prefer the urinal design that is deeper and more elongated, which allows men of most height to achieve a 30-degree angle. Researchers noted that the standard urinals produce 50 times splashback compared to their design. Also, a rounder urinal design with a triangular opening works as fine as the Nauti-loo, although it is not favored since it will not work for men of all heights.

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