The Worlds First 360-Degree Rooftop Infinity Pool
Updated: Jul 23, 2020
Infinity London could soon be the only building in the world to incorporate a 360-degree infinity edge pool.
You might have seen this one before when it broke the internet a couple months back. It was picked up by BBC, CNN, Guardian, New Your Post, People Magazine, Fox News, CNBC, and many other major news outlets across the world. It was even translated into over 20 languages and Twitter had a field day with one tweet every minute for 48 hours straight, collectively making this the worlds most talked about pool.
So what's all the hype about? Well, Infinity London as it's being called is a newly proposed 55 story high rise that will have a 5 star international hotel and a rooftop pool that's never been done before. If constructed, the swimming pool will be the worlds first 360 degree rooftop infinity pool integrated into a building. It'll also be an acrylic vanishing edge utilizing transparent panels on all sides including one in the floor. So not only will this pool look amazing from the exterior but guests will be able to appreciate it from inside the hotel as they look up through the floor of the pool. I guess that also means no skinny dipping...I'm disappointed already.
Compass Pools out of the UK is behind the design and they've actually been developing a proof of concept since 2017. It's a head turner for sure, similar to Londons Sky Pool that's soon to be the worlds first transparent pool that spans between two residential buildings. They're now working with developers from the UK and Dubai as well as with Superlux hotel chain to try and make this rendering a reality but the overall concept seemed to spark more questions than anything else; Especially from us pool pros.
So lets break down some of the obvious concerns in hopes that Compass has already taken them into consideration which I like to think they have. And like any concept car, beta program or even rendering, the final product almost always ends up looking and functioning a bit different than the initial concept.
To start, most people were seemingly more concerned with the entry and exit than I was. I actually think what was proposed would work although it may not be the most efficient form of circulation. Others, like this artist, weren't so sure.
In actuality, the entry and exit to this pool is based on the same concept as a submarine door. As Alex Kemsley, the Technical Director of Compass Pools describes, the system is basically a tube within a tube. The first outer tube raises up out of the floor via a hydraulic lift so you are left with a tube filled with water. Next, a programmed controller tells a pump to turn on which drains the tube of water back into the collector tank. Now you have an empty tube of air. Then, a spiral staircase raises up from the floor inside the empty tube which allows people to get in and out.
This design might actually be somewhat practical too. It's basically the same type of system used in movable pool floors with the addition of draining the water when the floor moves up. Movable pool floor systems like Aquatic Floors use hydraulic rams, pulleys and buoyancy tanks to move a floor, bench or steps up and down. So this entry/exit design could work. And for added safety, the tube has water sensors and safety switches connected to programmable controllers that regulate water level and mechanical controls. These types of controllers are commonly used in industrial applications like manufacturing or robotics that require high reliability control. This ensures water levels don't drain or fill when they're not supposed to and doors or mechanical devices don't move without the proper triggering of safety switches. There will also be a lifeguard in the pool at all times that will have physical control of the staircase and underwater cameras can automatically trigger the staircase to open in case of an emergency.
Swimmer safety and falling over the edge was another big concern for most people. From the looks of it, it'd be fairly easy to swim up to and fall out of the pool. But in reality, this is no lesser or greater risk than any high rise building in the world. If I wanted to jump off a balcony at the East Hotel in Brickell, what's going to stop me? Maybe a song by Third Eye Blind but as long as these buildings have railings that meet code, there's only so much you can do. The pool is said to be 4.5' deep so you'd have to willingly climb up and over the edge in order to fall to your death in which case I fully support Darwinism. As designers, we can't possibly design anything that's 100% safe because there's no telling what lengths someone will go to. I have to admit, for someone to even attempt to climb out onto the edge of a pool at the top of a 55 story building, you'd have to be either the ballsiest or dumbest person in the world.
But the pool will also have underwater cameras with alarms to monitor swimmers as well as an in pool staff member like a lifeguard to watch over bathers and assist with the entry and exit. It's also going to have lights in the floor which should make it look pretty sweet at night.
55 Stories High
At 55 stories up, this pool would also be almost 800' in the air easily making it one of the highest outdoor pools in the world. There's only a handful of pools in general that reach these types of heights and even fewer that are outdoors.
To give you an idea, of the 10 highest swimming pools in the world, one of the highest outdoor pools happens to be the Burj Khalifa pool which you may know as the tallest building in the world. This pool is on the 76th floor but it's hardly a full swimming pool size so I can't really say this one counts. It's more of a private splash pool than anything else but for argument sake, technically it's higher.
Currently The Marina Bay Sands Skypark Infinity Pool in Singapore holds the record for the highest pool in the world at 57 stories up and I must say, it's a sight to see. It's also the highest Infinity edge pool but given what we know about building story heights, it's possible a 55' high swimming pool that would be Infinity London, could possibly be higher.
It's hard to say exactly which pools are highest because building stories are usually based on floor to ceiling height which can vary per building. But of the handful of highest outdoor pools in the world, the newly proposed Infinity London would definitely give some of these a run for their money. And even if Infinity London doesn't end up taking the throne for highest outdoor pool in the world, it's definitely unlike anything we've ever seen from a swimming pool.
At this height, Infinity London is sure to see some serious winds too. So in an effort to reduce water consumption via splash out from winds, Compass Pools has included an anemometer as part of the hydraulic design. An anemometer is a device used for measuring wind speed that's also commonly used at weather stations. In this case, it will measure the wind speed and adjust the pump or even turn it off when winds get too high. This will reduce the potential for water loss but if some splash out still occurs from bather displacement or wind, the building is also tapered. The bottom of the building is roughly 23' wider than the top so any water that does splash out shouldn't reach the ground or splash on anyone.
Lets get technical
Apparently Infinity London is going to be about 160,000 gallons which is some serious water weight but more importantly, if we reverse engineer the supposed water weight and depth, we end up with around 5000 sq. ft. which in the shape of a square would give us an approximate pool size close to 70' x 70'.
(to achieve 160,000 gallons at 4.5' deep we need to find the surface area of the pool which is L x W and multiply that number by 7.5 or 7.48 if you want to be a dick, and then by 4.5 to get the volume or gallons. So, 70'L x 70'W = 4900 sq. ft. x 7.5 = 36,750 x 4.5D = 165,375 gallons; - I was close)
This is important for a couple of reasons. First off, this gives us the approximate length of each of the sides which gives us an idea of how thick the acrylic panels need to be. Now, I’ve worked with Reynolds Polymer and Aquatic Glazing International on numerous projects incorporating acrylic panels and acrylic panel vanishing edges. We even designed a 66' long single piece acrylic panel vanishing edge for a pool in Miami Beach. That panel was 3' high and 3" thick but it was also supported on 3 sides by a concrete structure.
The Infinity London concept shows the acrylic around the entire perimeter of the pool unsupported by any mullions or structures in the corners. This is still perfectly achievable but when an acrylic panel turns a corner without any vertical support, jamb or mullion, it requires a significant increase in thickness which comes at a considerable cost and aesthetic. And even though commercial projects of this nature usually have the budget for these types of panels, it's more about the look of the required thicknesses. These panels would have to be closer to 8" or even 12" thick to properly chemically bond together in the corners and support the force of the water. To give you an idea, the panel thicknesses on the London Sky Pool are 8" for the walls and 12" for the floors. This is why even some of the most expensive pool projects use corner mullions like the one below.
The acrylic panels on Infinity London might also receive a decent amount of UV at this height which increases the expansion and contraction of the acrylic. Unlike standard vanishing edge or infinity edge pools that are built out of concrete, the acrylic material will expand and contract pretty severely from hot to cold temperatures. And because of this movement, hydraulic systems need to be up-sized to account for these fluctuations in order to move enough water over the entire edge.
This is all pretty standard in the world of high end pool design but with a perimeter edge of around 280 linear ft., you would roughly require about 1,680 gpm. to adequately move water over the top of the acrylic panels; probably even more considering their thicknesses. But the concern isn't so much with the flow rate as it is with the gutter because there really isn't one shown even though Kemsley does mention it in his video.
Vanishing edge or Infinity edge pools that force water over an edge to achieve the beautiful endless watery aesthetic, require a basin or gutter on the other side to catch the water. And these gutters usually take into consideration the height at which the water is falling. The higher the water is falling, the farther it is likely to splash. Not to mention splash out from bather displacement and wind; wind at 55 stories no less.
So the general rule of thumb is a 1:1 ratio meaning that if the height of the vanishing edge wall that the water is going to fall is 1' high, then the width of the basin or area to catch that water is also 1' wide; within reason of course. If you have a 10' high wall, you're not going to have a 10' wide basin. But on Infinity London we are dealing with a 4.5' high panel pushing almost 2000 gallons of water over the edge at a height of 55 stories in the air with people swimming and splashing around in it. I think it's safe to say, the gutter shown in the rendering, or lack there of, may not be sufficient.
But although some details aren't clearly depicted from the renderings, it's hard to assume all aspects of design haven't been taken into consideration by the Compass team. I don't imagine anyone could propose a pool of this caliber without knowing what they're doing; but I've been wrong before too. That said, it seems Compass Pools has taken all the right precautions regarding functionality, efficiency and safety even if it's not shown in the images. They're just renderings after all and I find very rarely that conceptual images match finished products especially when talking about minute details.
Either way, I'm hoping this one goes through and I'll be following up to see if it does. I'm curious how this one might turn out, excited to see it take shape and can't wait to dive into this one when it's complete.