Kings Cross Fire: Background To The Trench Effect

This video, extracted from the original VHS video, provides an overview of the discovery of the trench effect at the Harwell Laboratory through computer simulations, and its subsequent verification by large scale experiments. This effect, in which flames rapidly extend up the escalator trench, is believed to be responsible for the rapid spread of the fire into the King's Cross Booking Hall. (Fennell Report).

[@ajs41]

One of my favourite videos on UA-cam, because it shows how computers in the 1980s could be used to achieve stunning results in terms of furthering scientific understanding.

[@ianjones9273]

Nice comment. The power of the machine we used is equivalent to a lower end IPad with 2GB of memory, shared between 4 processors. We do forget how things have moced on.

[@cherylm2C6671]

Thank you for sharing this video. Was about 10:00 is when the ceiling paint began to decompose? This would have created a ladder of volatile, low pressure vapor to raise the wood methane fire out of the Coanda effect in the trench and into the (people) air space where there was more oxygen? The Wikipedia article mentioned an 'explosive' outburst of flames, which some videos of trench effect do not show.

[@ianjones9273]

There still are photographic units in the successor organisations to UKAEA at Harwell, eg Magnox, who kindly supplied the digital version of the video. Also, one of the photographic team, the excellent Eric Jenkins, is still working up there. Regarding the Mandelbrot set, similar distributed graphics tools were used to visualise it, with the number crunching carried out on the Cray, and displayed in real time on a Silicon Graphics workstation.

[@ajs41]

Thanks for uploading this video, I've always been interested in the trench effect.

[@karenelizabeth1590]

Back then they needed a Cray computer to render that

[@EmeraldClaws]

The Cray wasn't used for the rendering, but rather the calculations of the behaviour of the fire..

[@ken131]

Yeah, you're right

[@christopherblankenship6807]

That’s Cray-Z

[@joinedupjon]

Looks like what must have been an early appearance of the mandelbrot set on the wall in the final scene.
Bet Harwell doesn't have a photographic unit these days... UA-cams turning into a good resource for finding old corporate videos of research people were proud of doing, but I don't suppose that sort of video is being made anywhere anymore.

[@michaelford1124]

i wonder if there was cctv footage of the flashover, as there is footage of the fire when it was only slightly showing above the escalator

[@ianjones9273]

Not to my knowledge. The focus of this work was the rapid fire spread up the escalator, leading to the flashover. In the first scale trial, there was an expensive high res camera at the top of the escalator, but it got written of by the flames.

[@michaelw9285]

Is this the same narrator as Protect and Survive?

[@ianjones9273]

Probably. I think we used Patrick Allen, who did the series you mentioned. He has a very distinctive voice.

[@ajs41]

@@ianjones9273 Yes, he was also on the infamous Frankie Goes To Hollywood song Two Tribes saying things like "Mine is the last word you will ever hear, don't be alarmed".

[@BricktopsPigs]

Wow, good ear.
Those Protect and Survive clips used to shit me right up.

[@MostlyPennyCat]

That's Phillip of Burgundy - known to his enemies as 'The Hawk'
AND he did all the idents for E4.
And Vic & Bob too

[@nicksmith12]

Patrick also starred in The Wild Geese with Richard Burton and Roger Moore, as well as the Barratt Homes ads, when he was in the helicopter. A very fine voiceover artist.

[@hebneh]

I assume the escalator was moving upwards. I wonder if it remained functioning throughout the start of the fire, and if so, if that upwards movement assisted the flames in that direction? Probably the effect was negligible.

[@ianjones9273]

Escalator was stopped, so no effect. Motion of the driving chains under the escalator and the fire in the grease might have contributed to some spread in the early phases.

[@draph91]

@@ianjones9273 the grease was also heavily impregnated with fibrous materials (fluff from clothes, tickets and other small litter, human hair, rat fur, etc). I believe that was also a factor to the fire
and the metal sides of the escalator served to contain the flames and direct the temperature ahead of the fire.

[@sonyasever7625]

I hate when they put this eerue music on scary enough situation

[@djmips]

Damned smokers

[@sonyasever7625]

I want to watch the underground smokers reaction when they had known the cause of death for more than 30 people.