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Window Washing a Skyscraper Is Beyond a Robot's Reach
HughPickens.com writes "Patrick McGeehan writes in the NYT that the image of a pair of window washers clinging to a scaffold dangling outside the 68th floor of 1 World Trade Center have left many wondering why robots can't rub soapy water on glass and wipe it off with a squeegee relieving humans of the risk of injury, or death, from a plunge to the sidewalk? The simple answer, several experts say, is that washing windows is something that machines still cannot do as well as people can. "Building are starting to look like huge sculptures in the sky," says Craig Caulkins. "A robot can't maneuver to get around those curves to get into the facets of the building." According to Caulkins robotic cleaning systems tend to leave dirt in the corners of the glass walls that are designed to provide panoramic views from high floors. "If you are a fastidious owner wanting clean, clean windows so you can take advantage of that very expensive view that you bought, the last thing you want to see is that gray area around the rim of the window."
Another reason for the sparse use of robots is that buildings require a lot more maintenance than just window cleaning. Equipment is needed to lower people to repair facades and broken windows, like the one that rescue workers had to cut through with diamond cutters to rescue the window washers. For many years, being a window cleaner in Manhattan was regarded as one of the most dangerous occupations in the world: by 1932, an average of one in every two hundred window cleaners in New York was killed each year. Now all new union window cleaners now take two hundred and sixteen hours of classroom instruction, three thousand hours of accredited time with an employer and their union makes sure workers follow rigorous safety protocols. In all, there are about 700 scaffolds for window washing on buildings in New York City, says union representative Gerard McEneaney. His members are willing to do the work because it pays well: as much $26.89 an hour plus benefits. Many of the window cleaners are immigrants from South America. "They're fearless guys, fearless workers."
Another reason for the sparse use of robots is that buildings require a lot more maintenance than just window cleaning. Equipment is needed to lower people to repair facades and broken windows, like the one that rescue workers had to cut through with diamond cutters to rescue the window washers. For many years, being a window cleaner in Manhattan was regarded as one of the most dangerous occupations in the world: by 1932, an average of one in every two hundred window cleaners in New York was killed each year. Now all new union window cleaners now take two hundred and sixteen hours of classroom instruction, three thousand hours of accredited time with an employer and their union makes sure workers follow rigorous safety protocols. In all, there are about 700 scaffolds for window washing on buildings in New York City, says union representative Gerard McEneaney. His members are willing to do the work because it pays well: as much $26.89 an hour plus benefits. Many of the window cleaners are immigrants from South America. "They're fearless guys, fearless workers."
For a human, using a sponge and squeegee combo is probably the most effective way to clean a window. For a robot, I would imagine that the answer is something more like a pressure washer, with a hood which covers the work area and reclaims the wash water. The water would then be filtered and reused until the particulate count rose too high, at which point it would be flushed and replaced with fresh. A sheeting additive would be used to cause the water to run off without spotting.
This probably wouldn't replace human window washing entirely, but it seems like it has the potential to replace at least some of the washes.
I've often wondered if anyone has ever tried a project to make a building which washes itself, using a robot designed for the building, and a building designed for the robot. I can imagine many problems with such a project without even undertaking it, mostly related to critters taking up residence in the mechanisms and/or tracks, but if it operated continuously that might well eliminate some of those objections. A universal window washing robot has a more complicated task than such a device would.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
I'm shocked that those window cleaners make "up to $26.89" WTF seriously? They just bragged like that was a good number for that sort of work....? I guess, relatively speaking, it might be good for the alternative choices those workers have, but I sure as hell wouldn't do that for $26.89. Why is it that all the high mortality rate jobs have such shitty wages?
The original twin towers DID use robotic window washers. They were built in 1971.
This problem has already been resolved, but they didn't design the new building in a way that robotic window washers could be implemented easily.
Oops.
Cost seems like a good explanation. I have no idea how long it takes to wash an entire building, but at the pay rate quoted in the story they could employ two guys for a whole year for under $300,000. A really good machine would probably be a million dollars to design and implement and would still need maintenance and probably a full-time guy to operate it.
I find it hard to believe there isn't a technological solution to this that could limit exterior manual cleaning to something done every couple of years. The idea that some machine used on the old World Trade Center sucked seems like a weak excuse -- a car from the early 70s sucks now, too, compared to current cars employing modern technology.
Some ideas off the top of my head:
1) A self-contained pressure washing system that recycles its own water with some combination of sheeting chemistry, forced air and microfiber to ensure the window is clean. Hard to believe you can't design a machine capable of cleaning well.
2) Why not integrate a cleaning system into the window framing or structural system capable of washing either a bank of windows or several vertical floor sections? It might need fixing itself, but it could be combined with once-every-five years exterior maintenance and "thorough" cleaning.
3) Are there coatings or other materials science solutions that would make dirt and pollution less likely to stick to the windows and make cleaning necessary only every 5 years or when exterior maintenance was necessary?