- When plans for a 360-degree rooftop infinity pool in London were unveiled last week, they practically broke the internet.
- But people were asking one big question: How do you get in and out?
- The pool's designer, Alex Kemsley, has now explained in detail to INSIDER how it works.
- He also addressed safety concerns, what happens in storms, or if birds drop faeces in the water, and whether you could splash pedestrians below.
- Visit INSIDER's homepage for more stories.
When plans were revealed for the world's first 360-degree rooftop infinity pool in London last week, people around the world couldn't contain both their excitement and their confusion.
The pool, which is set to be atop a 55-storey skyscraper named Infinity London, could potentially be in construction as early as 2020.
"We felt like we broke the internet," Alex Kemsley, the pool's designer said afterwards.
The biggest question everyone was asking was: How do you get in and out? Although Kemsley, Compass Pools' pool designer and technical director, had shared an initial explanation, it still wasn't entirely clear in the eyes of many.
After INSIDER asked for further clarification, Kemsley shared a design of the top of the building and explained in more detail how it all worked.
"Essentially, it's a tube in a tube," Kemsley said. An outer tube rises up from the floor and fills with water from the pool, which is being displaced.
The water that has filled the tube then drains out and goes back into the balance tank — every commercial swimming pool has a balance tank that ensures the water level stays the same regardless of how many people are getting in and out of the pool, displacing water as they go.
There's then a dry, inner tube, which contains the spiral staircase and is entered via a door on the floor below. "You can't open the door until the outside tube has drained," Kemsley explained to INSIDER.
He imagines it would take about 30 seconds for the whole process to take place, from the outer tube rising to a person getting into the pool.
At the top, the outer tube sticks out above water level by about 30cm, "just so that the water doesn't then splash back down the tube."
The top step of the spiral staircase is roughly water level so once you're at the top, you just have to hop over the edge of the tube and into the pool — there'll also be an option to climb down some indentations in the outer tube if you prefer to enter the pool more gently.
The staircase has also been designed so that the top step is nearest the centre of the pool so there's no possibility of falling off the edge of the building.
When it's time for the staircase to go back down, the inner tube containing the staircase goes down first, the door shuts, the outer tube then fills with water, and the tube retracts, placing water back in the pool as it does.
Capeesh?
Some people had also expressed concerns that entering a pool via a tube wouldn't be safe, but Kemsley believes there's nothing to worry about.
"It's all linked to the PLC [programmable logic controller, 'a computer which interfaces with all sorts of things like pumps and switches and lights'] using what's called an interlock,"he explained.
"You have water sensors in the tube meaning that doors and mechanical devices can't move unless there's a safety switch triggered, so that stops the building flooding.
"Also, the floor below is what we call a wet floor, so if any water gets in there it simply drains down through tubes, through the building out into the street or drainage system. That means there's no risk of the floors below flooding."
Equally, some people had concerns about what would happen if there was a fire in the building.
"It's probably one of the safest buildings on the planet if there's a fire because we have a built-in water reservoir linked to the sprinkler system," assured Kemsley. "It's very, very simple to put out a fire in terms of opening the taps."
Kemsley also addressed the point that birds could drop faeces in the pool. "Yes, potentially they could poo in it. But this pool poses a lesser risk of birds pooing in it than a pool at ground-level, and certainly than pools near the seaside, so it's not really a risk that concerns us.
"In case a pigeon does poo in it, you have automatic dosing systems that monitor the chemical levels and a chemical, normally chlorine, would kill the bacteria from any pigeon poo."
Another question some people had was whether you could splash people on the ground form the pool. However, the building is, in fact, going to be tapered, meaning pedestrians below would be safe from any particularly energetic swimmers.
While there won't be a traditional lifeguard as there's nowhere for a high chair to go, there'll be someone in the pool who'll also control the staircase.
What's more, there will be underwater cameras linked to machine learning that can detect if someone's underwater for a period of time or in danger, which automatically triggers the staircase to come out.
"A lot of thought has gone into the safety side of things," Kemsley confirmed.
Kemsley also told INSIDER that there will be no swimming during thunderstorms, but swimming in the rain will be allowed: "It's going to be 30 degrees Celsius in there," he said. "Swimming in the rain is great, the steam will be rising."
The whole Infinity London project started life in 2017, and Kemsley is now in talks with hotel chains and developers in the UK and Dubai to make it happen.