Volunteered to supervise our building’s backflow inspection yesterday. What a fascinating distributed maintenance institution!
Big buildings have special valves to keep building water from being siphoned into the water supply. In SF, each has to be manually tested annually!
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It’s a neat variation of “how many piano tuners in Chicago?”. There are a lot of condos in SF! 10^5 is probably the right order. Test took 30m; with transit maybe one plumber can do 10 tests per day. That’s ~2500 tests/year/plumber: ~40 full-time backflow testers!
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And that’s just residential—apparently the tests get more complex for commercial and industrial, since backflow may not only pollute but contaminate the water supply.
~*~maintenance.gif~*~
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Very nicely done job of improving your industrial literacy 😀
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Let’s recognize the value of industrial literacy and commit to improving it—starting with ourselves.
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