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Saturday, June 3rd, 2023
@rj-schneider so it doesn't turn into a 250 pound cannon pancake if the gases in the pipes below should ignite and explode
That's a thought. It was a sanitary MH at the flowline of a major roadside ditch. What I posted was more sarcasm, my honest guess would be a major rain event didn't overload the sanitary system.
If we've ever had a sewer gas explosion, here in Houston, I hadn't paid attention, can't remember.
I might watch too many sci-fi/horror movies but, I got to wondering why you had to bolt a 250 Lb. MH lid.
I ran into bolted manhole lids when I did some work in Seattle. When I asked about it I was told they're bolted on so a high tide doesn't flood the pipes and push hundreds or thousands of lids out of the rims.
Some manhole lids, even heavy ones, are bolted here because making things idiot proof (ie. stopping people messing with sewers that should not be) is hard when they keep making "better" idiots.
I have encountered what are known as "Locking" manholes (or maintenance holes if you prefer).
You have to rotate the lid about 15° (clockwise? counterclockwise? I forget.) to release the "finger-like" protrusion on the underside of the lid from the slot on the ring. If you don't know it's a locking lid you can spend all day trying to get it open.
If you don't know it's a locking lid you can spend all day trying to get it open.
oh god .. you had to rotate it 15° ?? 😩
