Manhole cover question

[Breadfan]

For gutter minds, my mind is in the sewer for this one, as I'm referring to sewer manhole covers!

I interviewed someone for a position the other day, and I asked this question that I learned from someone awhile back. It sparked my memory so I thought I'd ask it here.

There are multiple answers, I know of about 5 or 6 right off the top of my head. Here it is:



Why is a manhole cover round?

[Tallboy]

It won't fall into the hole.

No corners to line up.

[Bluerauder]

Why is a manhole cover round?
1. Easy to remove and replace .... it lines up naturally.
2. Related to manufacturing process -- easier to drop forge.
3. Presents no flat, sharp edges regardless of travel direction. Easily recessed.
4. It fits the round hole. :rofl:

[martyo]

They are easier to play tittle-winks with!

[MAD-3R]

So when they pop, it's blunt force trama, not piercing damage

[Bobby Clobber]

Because the hole it fits in is too?:lol:

[merc]

Manhole are round because they don't have corners to bend, break off or that can puncture car tires.

[Breadfan]

Because the hole it fits in is too?:lol:
That was one of my original answers, it makes sense in that a sewer opening is generally created by drilling a hole, or atleast some probably are. The shaft down to the sewer is probably drilled out. Anything drilled would be round, and much harder to make square. :) So might as well make a round cover.




Good answers thusfar!!

[Dr Caleb]

A circle is the only shape that won't fall in on itself.

[Bluerauder]

That was one of my original answers, it makes sense in that a sewer opening is generally created by drilling a hole, or atleast some probably are.
Sewer lines and water mains are generally laid in excavated trenches that run down the middle of roads and streets. Your sewer and water line service runs from your house to the road/street in front of your property. Then that line feeds a larger pipe ... and so on. If either line breaks between your road and where it enters your house -- guess who pays to fix it?? Invert elevations and grades are particularly important in order to keep the flow moving.... thus it is easier to lay the pipe and survey it in using a trench arrangement.

[Breadfan]

Sewer lines and water mains are generally laid in excavated trenches that run down the middle of roads and streets. Your sewer and water line service runs from your house to the road/street in front of your property. Then that line feeds a larger pipe ... and so on. If either line breaks between your road and where it enters your house -- guess who pays to fix it?? Invert elevations and grades are particularly important in order to keep the flow moving.... thus it is easier to lay the pipe and survey it in using a trench arrangement.

Guess that makes sense huh, might as well lay the pipe before building the road. Well...if you needed a new opening you'd drill it. :D

[VERN]

Yep - round covers won't fall in.
Square and rectangle covers will and do fall in - and they are a pain to get back out. The real problem is what they hit and damage on the way down.

Marty - tiddly winks?? not with 250 pound manhole covers....

[martyo]

Marty - tiddly winks?? not with 250 pound manhole covers....

Come on Vern, to big guys like us that's child's play!

How is your family?

[Breadfan]

That leads me to another one of my answers. Since they're heavy, they're easier to carry when round - just roll 'em.

[STLR FN]

Talk about laying has me wanti....... nevermind. Gutterbrain in effect. :P

[Blackened300a]

They are round so they wont fall in the hole.
Here in NY you have a chance of getting zapped if you step on one.

Thats been happening quite often lately

[A98CVLX]

OK this is the most instering thread I have read here on mm.net