Monday, June 1, 2009

Let's start this out with a bang, not a whimper: what went wrong at the King's Cross tube fire.

Only last night I found myself lost
By the station called King's Cross
Dead and wounded on either side
You know it's only a matter of time

--Pet Shop Boys

I used to smoke. I smoked until the end of October of last year, and for the most part while I was doing it I damn well enjoyed it and wanted to be doing it. When I stopped wanting to smoke, I stopped smoking.

Since then I’ve managed to stay on the wagon except for one experimental pack, and I didn’t enjoy that enough to consider taking it up again. But even when I was a confirmed smoker, I made sure my damn matches were out when I put them in the ashtray or dropped them to the tarmac. I lit with a lighter if possible, but if I used matches I shook them out.

Imagine knowing you killed thirty-one people because you didn’t bother to shake out your match. Imagine turning on the telly once you got home and realized that it could have been your match that started one of the worst underground fires since the Couronnes disaster in 1903. Imagine the feeling of that realization.

I wonder who it was, and whether they ever knew they had been responsible.

On the evening of November 18, 1987, the disaster began with very little drama. Far beyond the point where any action could have saved the station, the scope of the conflagration was not understood: only after a little “cardboard-box-sized” fire roared into flashover and incinerated people where they stood in the King’s Cross tube ticket hall did anyone have the slightest idea just how bad an escalator fire could get.

To begin at the beginning it is important to understand the layout of King’s Cross-St. Pancras station. This is one of the great spaghetti junctions of subterranean London, connecting the British Rail stations of King’s Cross and St. Pancras with the Piccadilly, Victoria, Metropolitan & Circle, and Northern tube lines. Building this thing must have been an incredible engineering feat; in the tube line ticket hall model we can see some of the complexity of the station design, and in the money shot we can get a comprehensive look at just what a warren of tubes and tunnels and escalators and shafts this place presented.

We must remember that a lot of the technology in the Tube stations dated back to the beginning of World War II. On the night of November 18, 1987, the escalators leading from the Piccadilly Line to the King’s Cross tube ticket hall were—like all the other escalators in the system—largely made of wood. Varnished wood. Thin, worn, varnished wood, under which ran a ceaseless procession of metal chain wheels and track wheels lubricated with grease that had not been inspected or changed since before the cabbage crates came over the briny. In the intervening decades, grime and dirt and dust and bits of paper and sweetie wrappers and hair and rat fur and more grime and more dirt and more dust had settled into this grease, stirred in by the ceaseless wheels, forming a dark pudding of lubricant and matter.

Some time before 7:30 P.M., somebody, presumably a passenger leaving the Piccadilly Line platforms via escalator 4 to the main tube ticket hall, stood on the right side of the escalator and lit a cigarette with a match. He or she dropped the match without making sure it was out, and it fell between the side of the escalator and the running track. Underneath the wooden steps, this match landed in the highly flammable grease mixture. This sludge caught on fire, and continued to burn merrily, lighting the undersides of the steps on fire and causing tongues of flame to lick up on the right-hand side of the escalator about halfway up. The ignition of the grease wasn’t noticed at once. Around 7:30, a passenger reported seeing small flames and wispy white smoke to authorities in the tube ticket hall.

The staff on duty that night were unfamiliar with the King's Cross station. Several staff members were off duty or on limited duty due to illness. Passengers were told, as the fire seemed to be small and not dangerous, to leave the station via the Victoria Line escalators nearby. Trains continued to stop at the station and passengers continued to disembark. Just before the first fire engines had arrived at the station, at 7:43 pm, trains were first warned not to stop at King’s Cross.

At this point nobody, not the firemen investigating the situation nor the passengers moving through the station, was aware of what would happen next. The fire in the Piccadilly Line escalator shaft was growing out of all proportion, consuming the paint on the walls and ceiling as it expanded. At 7:45 pm—-we know exactly when, because the digital clock in the ticket hall stopped working as its wires were burnt through-—the flames roaring up the Piccadilly Line shaft exploded into the ticket hall in a violent flashover, igniting every surface in the room. Passengers who had been directed to bypass the Piccadilly escalators via the Victoria escalators found themselves arriving in a chamber suddenly filled with a floor-to-ceiling blowlamp flame roaring from the shaft to their right. Paint and synthetic materials in the room, burning, gave off intensely toxic fumes that asphyxiated those who were not burnt to death.

Firemen had arrived at King’s Cross about two minutes prior to the flashover. During this period various firefighting teams became separated from one another, unable to communicate by radio as these units did not work underground, and unable to reach one another visually due to the thick black smoke. Disoriented and suffering from the intense heat, firefighters and passengers alike struggled to find exits.

At the time of the flashover several transport policemen were still directing passengers to leave the station via the Victoria Line escalators, unaware of the danger. Once they realized the ticket hall above was in flames, these officers did their best to rescue injured passengers and evacuate them from the station via alternate exit routes, but found several of these locked off. It’s possible that more people could have been saved if the exits to the station had all been clear. When the fire was finally contained and extinguished, at 1:46 the next morning, thirty passengers and one fireman were dead.

With a disaster of this magnitude the public was extremely vehement in its demands for answers and solutions. Obviously, the fact that the escalators were made of flammable wood had played a major part in the fire, but was the wood itself solely to blame? Investigators examined the unburnt parts of Piccadilly Line escalator #4, where the fire had begun, and found some disturbing results. The fire of November 18 had not been the first such incident on this escalator: multiple scorch marks in the paint on the undercarriage of the escalator frame indicated that small fires had started many times under this particular escalator, and had-—by sheer luck—-not propagated further. The possibility of arson was investigated and dropped. When the state of the grease and filth under the escalator tracks was discovered, investigators tested this sludge to see whether a carelessly dropped match could ignite it, and on the first attempt managed to cause a fire that licked up through the escalator steps and grew until seven or eight minutes later it was extinguished.

They knew how the fire had started, now. After a fire at Oxford Circus station some little time before, smoking had been prohibited in Underground stations. However, passengers ignored the ban and routinely lit up on the escalators on their way out of the station. Burnt matches and smoker’s materials were found under the right side of the elevators leading out of King’s Cross. It was most likely a discarded match that had sparked the blaze.

But why had a fire that had seemed at first to be nothing more than a couple of little flames and some wispy smoke turned into an inferno capable of killing thirty-one people? Investigators turned to Oxford University to request a computer model of the fire and its propagation. What they found seemed so incredible they asked if the computer scientists hadn’t forgotten a major variable such as gravity: the model showed the flames from the burning escalator steps lying down as they crept up the incline, flowing along the level of the steps and scarcely peeking above the handrails-—effectively hiding the magnitude of the fire from anyone looking at it from an angle. This would later become known as the “trench” effect. The model showed the hot gases from this flame path spiraling up and clockwise round the top of the tunnel, blasting out into the ticket hall with lethal force.

Despite skepticism, investigators created a scale model of the escalator involved in the fire. Under controlled conditions, they lit the model on fire and observed how the flames behaved. Surprisingly enough, the model fire behaved exactly as the computer had predicted, with the fire lying down along the trench of the escalator and erupting with considerable violence into the model ticket hall above.

Eventually, it was concluded that the fire progressed along the following lines. Beginning with the accidental ignition of grease and dirt below escalator 4 approximately halfway up, the fire burned for some little time and apparently did not appear particularly serious or dangerous to police and fire personnel on the scene. However, it quickly began to spread up the escalator, lying along the level of the steps as per the “trench effect,” until the heat it produced plus the pyrolyzates resulting from heat damage to paints, varnishes, and other substances formed sufficient hot gases to flow violently upward into the ticket hall in a sudden burst of flame generally termed a flashover.

Could the thirty-one people who died in King’s Cross have been saved had any one of a number of key individuals acted differently? Perhaps. But as a result of the King’s Cross fire, not only were wooden escalators throughout the Underground required to be replaced with metal, but communications strategies between station personnel, police, and emergency response teams were clarified and streamlined; fire-suppression sprinkler systems in Underground machinery were required to upgrade to meet new regulations; and firefighting theory the world over gained a new and important understanding of flame progression up an inclined plane in an enclosed environment.

Perhaps they didn’t die entirely in vain. But can you imagine what it must be like to have been one of the people to discard a lit match on Piccadilly Line Escalator 4 the night of November 18, and to realize that it might have been your match to blame for all those deaths? Can you imagine what that must feel like?

I have to wonder who that was, and whether they knew, and whether they’re alive now—and what they feel, every time the anniversary comes round.

All images are borrowed without permission and transferred to my own hosting from the official investigation into the disaster. Read it; it’s a fascinating document and well capable of wasting a lunch hour or two.

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