In my life (so far), there has only been one entranceway of one building where - in hot weather - there was a pressure oscillation felt more than heard (indeed, perhaps *only* felt - albeit with the ears), reminiscent of a helicopter's relatively slowly whirling blades.
The first time I experienced it, I thought "That's odd... I wonder what causes that...", and then I quickly forgot about it (or more accurately, stopped thinking about it) as I got on with my day. But each time I revisited the building in hot weather, I would again experience the pressure oscillation and so a desire to know the cause grew.
POBT: "So I can still show you that space..."
LHS: "Wonderful! When?"
POBT: "Anytime you like."
LHS: "How about now?"
POBT: "Sure! It's just down the street and shouldn't take long."
LHS: "Great! Thank you!-Thank you!-Thank you!!!"
And so we went off to the old building. I felt a little odd going into the vacated (main) part of the building, but POBT seemed completely at ease - as I suppose they would, having used the space daily for many years.
Exhaust Fan Passageway in Old Building
And then, just as I was thinking there wasn't much of anything else to see, my acquaintance looked down at a small, square, under-floor access door and said "I wonder what's under here...". (Before moving, there had always been something over the access door, so they had never noticed it before.) POBT raised the cover and exclaimed in surprise 「なにこれ！！」 and stepped back.
well water in the Okuno Building was after construction began next door...). So - noticing that there were ventilation tubes in the well space that seemed to connect with the exhaust fan I had just seen, I can only suppose that they converted the well room into a regular room to rent and then had a smell problem (for the entire basement and maybe even the first floor), so they put in that large exhaust fan arrangement to have air constantly drawn into the basement rooms from outside, and then vented outside somewhere (presumably on the roof) via that powerful exhaust fan.
metal plate in the building that had the information recorded on it.
This is one of the things about living in Tokyo, where buildings (even very large ones) are quite often torn down after only a few decades - it's quite hard to keep track of what was where, when, and how all the pieces (past and present) of the city fit together in a coherent time-line.
Lyle (Hiroshi) Saxon