The problem of splashbacks in toilets

4 physicists found the right direction to pee

If you’re a male, you may have noticed that when you pee, splashbacks may be a problem because they go anywhere and you don’t know which is the right direction to give to your flow to avoid this problem.

Whether you use a urinal or stand when you use the toilet, pee may splash back on you or anywhere else, and you may be more worried if the splashback comes from a public urinal or toilet. The same happens when you share a bathroom with someone who usually stands when he pees, so you may find a fine layer of pee covering your bathroom floor.

The reason is that pee ricochets off the porcelain beyond the toilet or urinal when males urinate standing up, so you should stand closer to the urinal or toilet if you don’t want to get urine on your clothes.

This is the conclusion of four physicists from Brigham Young University’s Splash Lab, who studied splashback in 2013 applying their fluid mechanic’s knowledge.

According to Tadd Truscott, a professor of Mechanical Engineering at BYU, splashback is a real problem.

“In the absence of dividers between urinals, it would not be unlikely for urine droplets to travel a distance of 5 feet to the side of the urinator”, Dr. Truscott said. “And if someone were standing next to him, they would most definitely get small droplets of the other’s man urine on their pants and shoes”.

Truscott says he’s trying to figure out how much urine splashes while someone is standing to pee. However, he is sure that the issue affects both urinals and toilets.

“We do know that a male of average height urinating into a traditional toilet while standing will launch small droplets out of the toilet and onto the floor, cupboards, and shower curtain”, he writes.

“I have seen splatter marks nearly at eye level. No joke”, he adds.

These researchers created pee simulators consisting of thin nozzles that sprayed water into buckets or against hard surfaces.

They used high-speed cameras to shoot each simulation, and they came to numerous conclusions while watching splash in stunning, high-definition slow motion.

The first analysis found that standing close to the urinal is better. Plateau-Rayleigh instability is the technical name for when fluids stream through the air and shatter into droplets, and pee droplets splash more than a stream of urine. This may seem paradoxical, but every time you sit on a toilet seat at some inches from the water, you experience that.

Another finding was that a low angle delivers the least splash. The splashback is instead bigger when pee strikes the porcelain at a 90-degree angle. So when the pee simulator was aimed low, like just above the urinal’s drain, the splash was lesser and not angled back at the urinator. This is also an important reason to aim sideways in the urinal rather than straight.

However, toilet manufacturers seem to underestimate the problem, they concentrate more on design and technology claiming this issue is caused by bad use of the toilet rather than the toilet itself.

Nevertheless, a cheap solution for urinals has been invented, it just involves a sticker of a realistic fly that looks real and encourages men to aim at it while peeing. This way, users tend to orient their flow in the right direction which got toilets 85% cleaner.

But the cheapest solution is always to sit down on a toilet and pee, even if you’re a man, even though the majority of them still disagree with that, especially in public toilets.

Source priceonomics.com