Giant Poop Volcano ????

I'll bet that's a title you never thought you'd see! But there's actually some rationale behind the subject...

I know a fair amount about plumbing, but a question occurred to me tonight which I didn't have an answer for.

A little bit ago I was re-reading the thread here about an apparent fire/water-main leak high up in the WTC buildings after one of the planes struck.

Here

Someone in this thread mentioned how the leak might have been from a waste drain line (i.e. the sewer) (a gruesome thought indeed). Anyway, this got me to wondering about something. It's a crappy question, I know.

How does a waste riser in a 80-100 floor building actually work? Surely the waste can't be allowed to free-fall for 80-100 floors, can it? Are there baffles or something to slow the waste down? In an extreme skyscraper the velocities would be in the triple digits by the time the waste gets to the bottom floor, easily enough to shatter some pretty HD ductile iron pipe. How does this work?

And while we're on the subject of S# falling from the sky, a second question...

All of that falling waste must create a pretty good vacuum (or negative pressure) condition in the pipes above it, what keeps the pipes (and fixtures) above from collapsing and/or having the water sucked out of them? I assume it's vents, but wow, that must be a hell of a venting system (not something you'd ever want stand anywhere near, else you'd get sucked in!)

And, a 3rd crappy question...

Down near the bottom of these waste risers there must be a pretty big (like huge) over-pressure condition. What keeps the toilets on lower floors from not erupting like a giant volcano of poo? No P-trap would be able to stop that! (have this image of someone on the 2nd floor flushing the toilet and being ejected through the ceiling tiles!). What keeps the pipes from blowing apart?

I don't know why I never thought about any of this before.

Anyway, sorry for all the crappy questions, and thanks in advance.

The sheer physics and fluid dynamics of this question are pretty interesting, in a crappy sort of way.

The sheer physics and fluid dynamics of this question are pretty interesting, in a crappy sort of way.

a reply to: Flyingclaydisk

I believe the risers are not pressurized. In fact, the draining waste water in the risers should create a negative pressure at the top.

Whk gives a snip. 😂

A triple digit turd hitting the pavement....reminds me of a game the british air force do called speckles. Dont ask...look it up. It doesnt bear explanation on a family show like this.

I don't know, but there's a history channel on YouTube that addressed the conditions of Victorian sanitation ... Yikes!

Gas powered bath tubs and methane explosions from the sewage right and left.



The gas powered bath has to be my favorite though.

Imagine if a tornado hit a sewage plant.....that would literally be a chit storm.

a reply to: Flyingclaydisk

An easy solution would be to have the sewer risers go down on a slope instead of straight drop

Every so many floors runs across to the other side