調查人員如何找出火災源頭：英語精讀講義

November 18th, 1987.

1987年11月18日。

Like every night on the London Underground,

就像每個夜晚的倫敦地鐵一樣，

it's packed.

這裡擠滿了人。

A train on the Piccadilly Line has just pulled into King's Cross, 片語動詞

一列皮卡迪利線的列車剛駛入國王十字車站，

one of Britain's busiest stations.

這是英國最繁忙的車站之一。

The horde of passengers get off,

大批乘客下了車，

but as they squeeze their way up the old wooden escalators, 片語搭配

但當他們擠上老舊的木製電扶梯時，

one passenger notices a strange glow coming from within the escalator.

一名乘客注意到電扶梯內部發出了奇怪的火光。

It's on fire.

起火了。

10 minutes later,

10分鐘後，

the London Fire Brigade arrive on the scene 片語搭配

倫敦消防局趕到了現場，

to what is now a small escalator fire.

面對的只是電扶梯上的一場小火。

Nothing they haven't dealt with before. 文法

這不過是他們習以為常的狀況。

But in a matter of seconds,

但短短幾秒鐘內，

the entire escalator suddenly ignites,

整部電扶梯突然燃燒起來，

sending a jet of fire upwards and into the ticket hall,

噴射出一股火柱直衝上方並湧入售票大廳，

killing 31 people inside.

導致裡面的31人喪生。

Figuring out what exactly happened here was mind-boggling, 文法

弄清楚這裡究竟發生了什麼是極其困難的，

and it led investigators down a 7-month rabbit hole 慣用語

它讓調查人員陷入了長達7個月的漫長探尋，

until they eventually discovered a unique physical phenomena

直到他們最終發現了一種獨特的物理現象，

completely unknown until this point

一種在此之前完全不為人知的現象，

that allowed the fire to behave in mysterious ways.

正是它使得火勢表現得如此詭異。

We animated the entire thing to show you how investigators locate the source of a fire

我們將整個過程製作成動畫，向你展示調查人員是如何尋找火源的，

and how early computer simulations led to the discovery of this gravity-defying effect.

以及早期的電腦模擬是如何帶來這種反重力效應發現的。

Even in a large fire,

即使在大型火災中，

buildings usually don't burn all the way to the ground.

建築物通常也不會完全被燒毀至平地。

Firefighters normally arrive in time to control the fire,

消防員通常能及時趕到控制火勢，

leaving behind a scene full of clues and evidence that can lead investigators to the source.

留下一個充滿線索和證據的現場，引導調查人員找到起火點。

By systematically narrowing down the search to the rooms with the most damage, 文法

透過系統性地將搜尋範圍縮小到受損最嚴重的房間，

they can start looking at the details.

他們可以開始研究細節。

Fire burns upwards and outwards.

火焰是向上和向外燃燒的。

And so when an object burns next to a wall,

因此，當一個物體靠牆燃燒時，

it creates a distinct V-shape that widens out closer to the ceiling.

它會形成一個明顯的V字形，越靠近天花板就越寬。

If the object is slightly further from the wall,

如果物體離牆稍微遠一點，

it creates more of a U-shaped burn mark

它則會形成一個更偏向U字形的燃燒痕跡，

since the tip of the fire doesn't touch the wall.

因為火焰的頂端沒有接觸到牆壁。

In a small simple fire that gets put out early, 片語動詞

在被及早撲滅的小型簡單火災中，

these burn marks usually point towards an obvious source of the fire.

這些燃燒痕跡通常指向一個明顯的火源。

But once a fire spreads to multiple objects,

但一旦火勢蔓延到多個物體，

these burn patterns start blending together.

這些燃燒圖案就會開始融合在一起。

On top of that, 表達脈絡

除此之外，

fire can get pulled towards openings like doors and windows,

火焰會被門窗等開口吸引，

where the abundance of oxygen helps the fire grow.

那裡充足的氧氣有助於火勢蔓延。

This can leave some areas of the room looking more damaged than the actual source.

這可能會使得房間的某些區域看起來比實際的起火點受損更嚴重。

Take a look at this room,

看看這個房間，

for example.

舉個例子。

Is it obvious where the fire started?

起火點在哪裡明顯嗎？

We can see multiple V-patterns,

我們可以看到多個V字圖案，

but this area here looks more burnt.

但這裡的區域看起來燒得更嚴重。

It's possible that the fire started here,

有可能火是從這裡開始的，

but worked its way up to the curtain, 片語搭配

但一路向上燒到了窗簾，

dropping burning debris onto the sofa.

將燃燒的碎片掉落到了沙發上。

Then eventually,

然後最終，

the window smashed with the heat and allowed fresh oxygen to flow in,

窗戶因高溫碎裂，新鮮的氧氣流了進來，

drawing the fire towards that side of the room.

將火焰引向了房間的那一側。

But wait,

但是等等，

if you lift up the carpet,

如果你掀起地毯，

you'll see what looks like liquid stains. 文法

你會看到看起來像液體污漬的痕跡。

This can be a sign that something like gasoline was used to quickly and deliberately start the fire. 片語搭配

這可能是一個跡象，表明有人使用汽油之類的東西迅速並蓄意縱火。

If an investigator suspects arson,

如果調查人員懷疑是人為縱火，

they can send in a sniffer dog,

他們可以派出一隻嗅探犬，

specially trained to sniff out these kinds of flammable substances. 片語動詞

專門訓練來嗅出這類易燃物質。

If none of this leads towards an obvious source,

如果這些都沒有指向一個明顯的火源，

the investigators will look towards the objects themselves.

調查人員就會把目光投向物體本身。

When materials reach a certain temperature,

當材料達到一定溫度時，

the water molecules and other organic compounds inside turn into gas,

內部的水分子和其他有機化合物會變成氣體，

leaving behind a layer of carbon.

留下了一層碳。

This is known as char. 用詞

這就是所謂的炭化層。

As the material keeps burning,

隨著材料繼續燃燒，

it works its way inward towards the fresh unburnt material,

它會向內侵入尚未燃燒的新鮮材料，

leaving behind a thicker and thicker layer of char over time. 文法

隨著時間的推移，留下的炭化層會越來越厚。

And so by measuring the char depth of similar materials at various points in the room,

因此，透過測量房間內不同位置相似材料的炭化深度，

investigators can build up an image of which areas started burning first.

調查人員可以建構出一幅圖像，顯示哪些區域最先開始燃燒。

This doesn't give a definitive result,

這並不能給出一個確切的結果，

but it can help lead them closer to a possible source.

但它可以幫助他們更接近可能的起火點。

But what happens when a fire defies all of these rules?

但是，當一場大火打破所有這些規律時，會發生什麼呢？

In the London Underground fire,

在倫敦地鐵火災中，

eyewitnesses reported the fire behaving in strange ways.

目擊者報告說火勢表現得很奇怪。

It wasn't burning upwards,

它不是向上燃燒，

but at an angle,

而是呈一個角度，

perfectly horizontal to the escalator.

與電扶梯完全平行地燃燒。

This baffled the investigators for months until they tried recreating the fire on one of the most powerful supercomputers around,

這讓調查人員困惑了幾個月，直到他們嘗試在當時最強大的超級電腦之一上重現火災場景，

Odoo.

那就是Odoo。

Just kidding. 語氣意圖

開個玩笑。

Odoo is actually an all-in-one business management software

Odoo實際上是一款多合一的商業管理軟體，

that gives entrepreneurs access to more than 45 apps to simplify the daily management of their business.

它讓企業家可以使用超過45個應用程式來簡化他們企業的日常管理。

One of my favorites is the invoicing app.

我最喜歡的之一是開發票應用程式。

It's hands-down the quickest and easiest way to make invoices. 慣用語

這毫無疑問是製作發票最快、最簡單的方式。

Simply select one of your existing customers

只需選擇你現有的一個客戶，

and it automatically fills out their information.

它就會自動填入他們的資訊。

Then add your products and services,

然後新增你的產品和服務、

quantities, price, billing terms,

數量、價格、帳單條款，

then send it off by email. 片語動詞

接著透過電子郵件發送出去。

Your customer can pay online by using the customer portal

你的客戶可以透過客戶入口網站線上支付，

and choosing their preferred payment method.

並選擇他們偏好的支付方式。

With Odoo,

有了Odoo，

you can track invoices in real-time by connecting your bank,

你可以透過連接你的銀行來即時追蹤發票，

so you'll always know who has paid you and who still owes you money.

這樣你總能知道誰付了款，誰還欠你錢。

Perhaps the best part is that it isn't behind a paywall. 用詞

或許最好的一點是它沒有任何付費牆阻擋。

You can use it for free for life with Odoo's first app offer,

你可以透過Odoo的首個應用程式優惠活動終身免費使用，

including unlimited hosting and support.

包含無限期的代管和支援。

To get started with Odoo,

想要開始使用Odoo，

check out the link in the description.

請點擊描述中的連結。

The first Odoo application is free for life.

第一個Odoo應用程式是終身免費的。

After that,

在那之後，

as your business grows,

隨著你業務的增長，

you can easily add more apps when you need them

你可以在需要時輕鬆新增更多應用程式，

and have access to all applications at an affordable subscription.

並以可負擔的訂閱費用使用所有應用程式。

Escalator fires on the London Underground weren't uncommon.

倫敦地鐵的電扶梯起火並不罕見。

In fact,

事實上，

in the 30 years before the King's Cross fire,

在國王十字車站火災發生前30年裡，

more than 400 had been reported.

已經報告了超過400起火災。

Although smoking had been recently banned in underground stations,

儘管近期地鐵站內已經禁止吸菸，

people regularly broke this rule

人們還是經常違反這項規定，

and would often light up just before getting on the escalator. 片語動詞

而且往往會在踏上電扶梯前點上一根菸。

Matches and cigarettes would fall between the gaps,

火柴和香菸會掉進縫隙裡，

igniting the escalator steps,

點燃電扶梯的階梯，

which were still surprisingly made of wood in many underground stations.

當時許多地鐵站裡的階梯竟然還是木製的。

The thing is, 表達脈絡

問題在於，

these fires would almost always go out by themselves. 片語動詞

這些火往往都會自行熄滅。

So why did this one go from a small fire 文法

那麼，為什麼這一場火會在短短幾秒內，

to an enormous inferno in just a matter of seconds?

從小火苗變成一場巨大的地獄之火呢？

When investigators opened up the other escalators in the station,

當調查人員打開車站內其他的電扶梯時，

they noticed that a large amount of grease had built up. 片語動詞

他們注意到積聚了大量的油脂。

And according to staff,

據工作人員稱，

this hadn't been cleaned in years.

這裡已經很多年沒有清理過了。

Normally,

通常情況下，

this grease on its own would be very hard to ignite. 用詞

僅僅這些油脂本身是很難點燃的。

But after years of accumulation,

但經過多年的累積，

the grease was full of dust,

這些油脂裡吸滿了灰塵、

fiber, and debris that had dropped through the gaps

纖維，以及從縫隙掉落的碎屑，

after years of operation.

這些都是多年運作下來累積的。

The investigators tested this grease on an open model of the escalators

調查人員在一個開放的電扶梯模型上測試了這種油脂，

and found that it was very easy for lit matches to fall down the gaps,

發現點燃的火柴很容易掉進縫隙，

ignite the grease,

點燃油脂，

and start a small fire.

並引發小火。

But no matter what they did, 文法

但無論他們怎麼做，

the fire would always burn vertically

火總是垂直燃燒，

and eventually put itself out.

最終自行熄滅。

There was still something missing.

顯然還遺漏了什麼。

One of the main theories was that the ceiling paint,

當時一個主要的理論是，天花板上的油漆，

which was 20 layers thick,

有20層之厚，

had absorbed the heat,

吸收了熱量，

ignited, and caused the fire to spread up the escalator shaft.

發生起火，並導致火勢沿著電扶梯井蔓延向上。

But this went against the witness statements, 片語動詞

但這與目擊者的陳述相悖，

which claimed that the fire never touched the ceiling at all

目擊者稱火焰根本沒有接觸到天花板，

and instead stuck to the escalator steps all the way to the top.

而是一直緊貼著電扶梯階梯向上蔓延到了頂部。

To determine whether this was even possible or not, 文法

為了確定這是否真的可能，

a computer simulation was set up using the Cray-2 supercomputer,

他們使用Cray-2超級電腦建立了一個電腦模擬，

the only one that existed in the UK.

當時英國只有這一台 Cray-2。

This calculated the temperature and airflow of gas at various points

這台電腦計算了各個位置氣體的溫度和氣流，

to simulate how the fire might have spread. 文法

以模擬火勢可能蔓延的方式。

The result was astonishing.

結果令人震驚。

The simulation perfectly predicted that the flames and hot gases wouldn't travel upwards, 文法

模擬結果完美預測了火焰和高溫氣體不會向上方移動，

but instead hugged the entire length of the escalator steps.

而是緊貼著整個電扶梯階梯的長度行進。

This completely defied normal fire behavior,

這完全違背了正常的火災行為，

as you would expect the hot buoyant gases

因為你本以為那些高溫且具備浮力的氣體

to have a lot of upwards force.

會有很大的向上力量。

Here's what's happening.

實際情況是這樣的。

Thanks to the trench-like shape of the escalator shaft and its 30-degree angle, 片語搭配

由於電扶梯井呈現出溝槽狀的形狀以及它的30度傾角，

the flame couldn't spread outwards,

火焰無法向外蔓延，

and so the heat had to flow in the direction of the trench.

因此熱量只能順著溝槽的方向流動。

At first,

起初，

some of the flames did escape upwards through the gaps, 文法

確實有一些火焰從縫隙中向上逃逸，

but the majority were forced to travel under the escalator steps. 文法

但大部分都被迫在電扶梯階梯下方行進。

As this stream of hot gas accelerated up the escalator shaft,

隨著這股熱氣流在電扶梯井中向上加速，

its pressure dropped,

其壓力下降，

creating a difference in pressure above and below the steps.

在階梯的上方和下方之間形成了壓力差。

This gradually pushed the fire over

這逐漸將火焰推倒，

until it started sticking to the underside of the steps.

直到它開始緊貼在階梯的下側。

The hotter it burned, 文法

它燃燒得越熱，

the faster it traveled,

移動得就越快，

and the more it stuck to the steps.

它就越緊貼著階梯。

To witnesses,

在目擊者看來，

all they could see was a rather small insignificant fire halfway up the escalator. 文法

他們能看到的只是電扶梯中段那團相對較小、不起眼的火苗。

But beneath the steps,

但在階梯之下，

the hot gases were heating the entire length of the wooden escalator

高溫氣體正在把整條木製電扶梯

to temperatures well above 500°.

加熱到遠超500度的溫度。

Those hot gases were then funneling into the ticket hall 用詞

然後這些高溫氣體順著通道湧入售票大廳，

and filling up the void above the false ceiling.

並填滿了假天花板上方的空隙。

What happened next turned the small fire into a disaster.

接下來發生的事情將這場小火變成了一場災難。

When materials reach a certain temperature,

當材料達到一定溫度時，

they ignite automatically,

它們會自動起火，

causing the fire to spread almost instantly.

導致火勢幾乎瞬間蔓延。

This is known as a flashover. 用詞

這就是所謂的轟燃。

Eventually,

最終，

the escalator and hot gases reached this temperature,

電扶梯和高溫氣體達到了這個溫度，

and in an instant,

在瞬間，

everything ignited.

一切都被點燃了。

This sent a fireball rushing up the escalator and into the ticket hall,

這導致一個火球衝上電扶梯進入售票大廳，

igniting every surface and filling the place with fire and smoke.

點燃了所有表面，讓整個地方充滿了火焰和濃煙。

The computer simulation had shown this exact effect perfectly,

電腦模擬完美展示了這確切的效應，

but it wasn't fully believed until the investigators performed real tests

但直到調查人員進行真實的測試之前，它還沒有被完全相信，

on a scale model of the escalator shaft.

該測試是在電扶梯井的比例模型上進行的。

At first,

起初，

the fire burned upwards,

火焰是向上燃燒的，

but after just a few minutes,

但僅僅過了幾分鐘後，

it started lying down and hugging the floor of the escalator. 慣用語

它就開始伏低，並緊貼著電扶梯的地板燃燒。

This brand new discovery was named the trench effect, 用詞

這項全新的發現被命名為「溝槽效應」，

and it led to a bunch of new safety improvements.

它促成了一系列新的安全改進措施。

All the wooden escalators were replaced,

所有的木製電扶梯都被替換了，

and heat detectors were added beneath escalators with automatic sprinkler systems.

並在電扶梯下方增設了熱探測器和自動灑水系統。

Thanks for watching,

感謝觀看，

and I'll see you in the next video.

我們下期影片再見。