Physicists design quieter airplane toilet to cut down on roaring flushes

It took a group of physicists two years to develop an airplane toilet that they say drastically reduces the widely-loathed noise levels of its predecessors. 

‘People have told us they don’t want their kids to be scared to use the bathroom on a flight,’ said lead researcher Kent Gee, BYU professor of physics. ‘So, we’ve used good physics to solve the problem.’

While the problem may seem like a simple one, especially for some of the country’s most reputable physicists, researchers say that dulling the roar of passenger’s in-flight bathroom experience was anything but. 

Plane toilets use a vacuum to release a torrent of water and waste that can travel at 300 MPH.

Because the toilets require a vacuum to flush with very little water, speeds, and therefore noise, of one’s typical flush tend to reach much higher levels. 

In fact, researchers say that in an airplane flying at 38,000 feet air pulls the water down at nearly half the speed of sound. 

The results they say are not only scary to small children and unpleasant for those using the toilet, but for the rest of the passengers forced to hear the noise repeatedly. 

‘Airline companies have always had standards for the toilet noise, but they’ve never met those and there has never been much pressure to do so,’ said researcher, Scott Sommerfeldt. 

‘Now with the reduced cabin sound levels, the sound of the toilet flushing is more noticeable and customers are pushing back.’   

To help solve the problem, researchers say they pinpointed two key aspects of how airplane toilets currently operate. 

One aspect, they said, is the distance of what is called the flush valve. In their model, the device is located much further away from the opening which helps mitigate how readily the sound travels throughout the bowl.

Another step, they said, was to soften the angle of the pipes. 

While regular piping may cut at at an almost 90-degree angle, researchers designed a system with a more gradual trend that they say also reduces the sharpness of resultant noise. 

Airplane toilets can be scary for kids and generally just scary loud for everyone forced to use them.

The results? According to their measurements, noise levels were reduced in some cases by more than half, from about 16 decibels to as low as five.

The technology can be easily installed by only removing a couple of parts and can also be applied to cruise ships and some green buildings that look to cut down on water usage. 

‘At the end of the day, this is about using science to improve a user experience,’ Gee said. ‘It’s an important part of making flights more comfortable for customers.’