The sequence for opening the tower manholes after shutting down is from top to bottom
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Could you please explain the reason? I’m a bit confused.
I originally heard that there was concern that materials might still be left in the lower part and not have been completely removed.
Repost: The main consideration is ventilation. Before opening it, the container is sealed; if one tries to open it from bottom to top, it’s difficult to access the top manhole due to the high concentration of toxic and harmful gases inside. By opening it from the top first, there is no convection inside, so the toxic gases don’t easily escape, which makes it easier to open the manhole. The same principle applies when sealing the manhole. http://bbs.hcbbs.com/thread-898858-1-1.html
Assuming that the manhole opens from bottom to top, if there are flammable gases inside the tower, the incoming air will mix with them to form explosive gases that remain at the top of the tower; everyone should be aware of the danger this poses； Manholes are opened from top to bottom; air convection can occur between the manholes at the top and bottom, which helps to carry away flammable gases and toxic gases, thereby increasing safety.