6 replies to this topic

[skookum]

I found this footage taken in Peterborough. Really weird.

http://www.telegraph...ng-manhole.html

[Englishgent]

The local Fire Brgade said it was possibly wires overheating?
I am no expert in this matter but I would have thought that wires overheating would not have caused such an explosion unless there was some other flammable element such as gas involved.

[skookum]

Englishgent, on 24 November 2011 - 10:21 AM, said:

The local Fire Brgade said it was possibly wires overheating?
I am no expert in this matter but I would have thought that wires overheating would not have caused such an explosion unless there was some other flammable element such as gas involved.

I was wondering about that, I can see melting and arcing wires being a source of ignition but what is the fuel for the fire.  Plus being phones surely loads of people would have reported their phones dead after as I can't see the wires being intact after that.

[MissMelsWell]

Beleive it or not, they've done an episode of this on Mythbusters. It CAN happen and it's pretty impressive. On Mythbusters, they actually managed to create a mini sewer, and blow their test manhole covers like 100ft in the air.

Sewers are full of waste, and waste creates methane which is highly explosive. if it's ignited, it most certainly can explode and send manhole covers flying! In fact, the test sewer explosion they built on Mythbusters looked a lot like the one in the video in the OPs link.

It's rare that it happens though... there are all kinds of conditions that have to be met, so it's not like any old sewer can rocket itself into oblivion, but its possible, typically with older sewer systems. The newer ones are designed to prevent this kind of accident.

Edited by MissMelsWell, 24 November 2011 - 04:27 PM.

[Englishgent]

MissMelsWell, on 24 November 2011 - 04:27 PM, said:

Beleive it or not, they've done an episode of this on Mythbusters. It CAN happen and it's pretty impressive. On Mythbusters, they actually managed to create a mini sewer, and blow their test manhole covers like 100ft in the air.

Sewers are full of waste, and waste creates methane which is highly explosive. if it's ignited, it most certainly can explode and send manhole covers flying! In fact, the test sewer explosion they built on Mythbusters looked a lot like the one in the video in the OPs link.

It's rare that it happens though... there are all kinds of conditions that have to be met, so it's not like any old sewer can rocket itself into oblivion, but its possible, typically with older sewer systems. The newer ones are designed to prevent this kind of accident.

Hi MissMelsWell.
Yes, I fully agree that manhole covers over sewers can do this. However, the news article in question says this manhole covers some electrical cables, not a sewer.

[Professor T]

Check this out.

This is a sewer explosion taking out an entire roadway..


And this Is a man lighting Methane gas and sending himself & a manhole cover flying.

Edited by Professor T, 26 January 2013 - 02:10 AM.

[BiffSplitkins]

skookum, on 24 November 2011 - 10:02 AM, said:

I found this footage taken in Peterborough. Really weird.

http://www.telegraph...ng-manhole.html

That almost looks like pyrotechnics to me.