Bring Back the Paternoster

You always had your own cab in this old elevator design.

Paternoster in Rotterdam
Paternoster in Rotterdam.

coolsingel 42 on Wikipedia

The elevator is what made high rise buildings happen. But they are also a real problem in the post-coronavirus world, where one is stuck in a tiny box with other people you don't know. Ben Guardino writes in the Washington Post about the new rules: "Wear masks. Tap buttons with an object or knuckle. Avoid speaking when possible." There are also plans by many building managers to reduce the number of people that can ride in an elevator at one time; at One World Trade Center, a cab that carries ten people will be limited to four.

The problem is that in every modern office building, elevator consultants determine the number of elevators needed in a building based on the estimated occupancy of the building, the speed of the elevators, and the capacity of the cab. If you cut the capacity to 40%, all those calculations go out the window. In some buildings with smaller cabs, they may be forced to limit capacity even more to maintain a six-foot distance between passengers. As Joseph Allan of the Healthy Buildings program at the Harvard T.H. Chan School of Public Health told the Post:

“That really means that they’re saying one person per elevator ride,” he said. “In some of these big buildings, if we have one person ride an elevator, we are going to have hundreds, if not thousands of people in the lobby. And that creates a greater exposure.”

Now we are getting into serious management problems, where it might be necessary to stagger work hours and lunch hours so that there is not so much pressure on particular times. It might even become necessary to schedule elevator rides.

Bring Back the Paternoster

Perhaps what we need is a different kind of elevator, like the paternoster. It's a continuously moving series of boxes that you jump into as it moves by and jump off when it passes your desired floor. They are a lot of fun, and carry a lot of people; According to Anne Quito in Quartz,

One BBC experiment proved how the paternoster—'our father,' in Latin, a reference meant to evoke the lift system’s similarity in shape to rosary beads—moves people much faster than traditional elevators. Using the University of Sheffield’s paternoster (the world’s tallest) the BBC demonstrated how 50 students can travel 18 floors up in less than 10 minutes. In comparison, the school’s conventional lift managed to transport only 10 students in the same amount of time.

They are a lot of fun to use too; no buttons to push, not much waiting (a few people might go by but you are never bored) and no sharing.

What could possibly go wrong? Lots – they are dangerous. Quito at Quartz writes:

Tales of paternoster mishaps abound: falling in, broken limbs, even a fatal accident that resulted in a European ban on new paternosters in the 1970s. In 2015, Germans were consumed by a proposal that would require people to obtain a license before being allowed to board one of the country’s antique paternosters.

They are also useless for people with crutches or baby carriages, or who have disabilities that would make it a leap of faith to leap onto the cab. They are certainly not universally accessible.

Bring on the MULTI

MULTI Mechanism doing the twist
MULTI Mechanism doing the twist.  Lloyd Alter

Yet there is a modern, safe version of the paternoster that won't kill people: the MULTI made by ThyssenKrupp, the big elevator company. In the interest of full disclosure, I have been a guest of the company a number of times to follow the progress of the MULTI, and have written about it on TreeHugger before. I was most intrigued by the way it went "sideways, slantways and backways," to quote Willie Wonka. But it also has some real advantages in the era of the coronavirus.

Like a paternoster, the MULTI has lots of little cabs running up one side of a shaft and coming down the other side. What's different is that they are not all connected by a cable, but run independently on linear induction motors so that they can actually stop at floors to let people on or off. When it gets to the top (or wants to go sideways) the cab stays upright, but the mechanism holding it rotates 90 degrees, it slides sideways to the down-side of the shaft and then rotates again.

Dennis Poon and Lloyd Alter in a Multi cab
Dennis Poon and Lloyd Alter in a Multi cab. Lloyd Alter

The cabs are necessarily small and light, made from carbon fiber, because these motors are really expensive, and there's another cab coming in twenty seconds anyway.

The problem with this is that there is another cab coming up the shaft behind you. The best analogy I can come up with is the high-speed chair lift at a ski hill: all the chairs move together until one unclamps from the cable, and the one behind gets closer and closer until it clamps on again and scoots away.

A similar scenario happens on the MULTI; if the cab you are in stops, then you have a fixed amount of time to get off while the next cab behind is still moving closer. That means it needs some space and probably can't stop at every floor. This makes it great for an express system where you transfer to another elevator for the in-between floors.

But one can think of other scenarios; perhaps every MULTI could be paired with a really attractive stair that you can walk down a few floors to your destination. Or if each MULTI could stop at every five floors, there could be five separate shafts, which isn't more than you get in a lot of buildings; just make sure you get on the right MULTI.

No doubt there are other scenarios, but the basic idea remains that of the paternoster: a continuous stream of little cabs that can carry one or two people, more like a vertical escalator than an elevator as we know it. And because there are so many cabs in one shaft, building designers can get away with fewer shafts yet carry the same number of people.

Other Measures to Kill the Coronavirus

While aerosols or exhaled water droplets carrying the virus are considered to be the main method of transmission, there is also worry about the virus collecting on surfaces. Perhaps the cabs will be voice-activated, or there might be a powerful UV-C light that comes on to sterilize the cab when it is empty.

Isn't This All a Bit Extreme?

After previous posts discussing the design of the office after the coronavirus, readers have complained that at some point we will have a vaccine and we will then all go back to normal. But "normal" has never been optimal; I have always hated elevators. My dentist is on the eighth floor of a medical building and I always walk up, not wanting to be in a small cab with sick people. Besides, putting one little box in a shaft running the full height of a building never made much sense anyway, you might as well fill it with a lot of boxes instead. I suspect that in a couple of years every new building will have elevators like the MULTI.