第1自然段

On 2nd August 1999, a particularly hot day in the town of Cirencester in the UK, a large pane of toughened glass in the roof of a shopping centre at Bishops Walk shattered without warning and fell from its frame. When fragments were analysed by experts at the giant glass manufacturer Pilkington, which had made the pane, they found that minute crystals of nickel sulphide trapped inside the glass had almost certainly caused the failure.

    1999年8月2日，英国Cirencester镇的一个特别炎热的日子，位于Bishops Walk的一家购物中心的屋顶上的一块大型钢化玻璃突然无警告地破裂并从框架上掉落。当玻璃制造商Pilkington的专家对碎片进行分析时，他们发现被困在玻璃内部的微小硫化镍晶体几乎肯定是引起破裂的原因。

第2自然段

‘The glass industry is aware of the issue,’ says Brian Waldron, chairman of the standards committee at the Glass and Glazing Federation, a British trade association, and standards development officer at Pilkington. But he insists that cases are few and far between. ‘It’s a very rare phenomenon,’ he says.

“玻璃行业意识到了这个问题，”英国玻璃和玻璃幕墙联合会（Glass and Glazing Federation）标准委员会主席、Pilkington标准发展官员布赖恩·沃德龙表示。但他坚称这类案例很少而且很少见。“这是一个非常罕见的现象，”他说。

第3自然段

Others disagree. ‘On average I see about one or two buildings a month suffering from nickel sulphide related failures,’ says Barrie Josie, a consultant engineer involved in the Bishops Walk investigation. Other experts tell of similar experiences. Tony Wilmott of London-based consulting engineers Sandberg, and Simon Armstrong at CladTech Associates in Hampshire both say they know of hundreds of cases. ‘What you hear is only the tip of the iceberg,’ says Trevor Ford, a glass expert at Resolve Engineering in Brisbane, Queensland. He believes the reason is simple: ‘No-one wants bad press.’

不过，其他人持不同意见。参与Bishops Walk调查的咨询工程师巴里·乔西表示：“平均每个月我都会看到大约一两栋建筑物出现由于硫化镍相关故障。”其他专家也讲述了类似的经历。伦敦咨询工程师公司Sandberg的托尼·威尔莫特和Hampshire的CladTech Associates的西蒙·阿姆斯特朗都表示他们了解到了数百起类似事件。“你听到的只是冰山一角，”昆士兰布里斯班Resolve Engineering的玻璃专家特雷弗·福特说。他认为原因很简单：“没有人愿意过差评。”

第4自然段

Toughened glass is found everywhere, from cars and bus shelters to the windows, walls and roofs of thousands of buildings around the world. It’s easy to see why. This glass has five times the strength of standard glass, and when it does break it shatters into tiny cubes rather than large, razor-sharp shards. Architects love it because large panels can be bolted together to make transparent walls, and turning it into ceilings and floors is almost as easy.

钢化玻璃无处不在，从汽车和公交车站的玻璃到全球成千上万座建筑物的窗户、墙壁和屋顶。这很容易理解。这种玻璃的强度是普通玻璃的五倍，在破裂时会形成小方块而不是大而锋利的碎片。建筑师喜欢它，因为可以将大型玻璃板螺栓连接在一起制作透明墙壁，而将其变成天花板和地板几乎同样简单。

第5自然段

It is made by heating a sheet of ordinary glass to about 620℃ to soften it slightly, allowing its structure to expand, and then cooling it rapidly with jets of cold air. This causes the outer layer of the pane to contract and solidify before the interior. When the interior finally solidifies and shrinks, it exerts a pull on the outer layer that leaves it in permanent compression and produces a tensile force inside the glass. As cracks propagate best in materials under tension, the compressive force on the surface must be overcome before the pane will break, making it more resistant to cracking.

制造钢化玻璃的方法是将一张普通玻璃片加热到约620℃，稍微软化使其结构膨胀，然后用冷气喷射快速冷却。这导致玻璃面层收缩并凝固，然后内部再次凝固和收缩，对外层施加拉力，使其永久压缩并在玻璃内产生张力。由于裂纹在受拉材料中传播得最好，必须克服表面的压缩力才能使玻璃破裂，从而使其更抗开裂。

第6自然段

The problem starts when glass contains nickel sulphide impurities. Trace amounts of nickel and sulphur are usually present in the raw materials used to make glass, and nickel can also be introduced by fragments of nickel alloys falling into the molten glass. As the glass is heated, these atoms react to form tiny crystals of nickel sulphide. Just a tenth of a gram of nickel in the furnace can create up to 50,000 crystals.

问题发生在含有硫化镍杂质的玻璃中。通常原料中都含有微量的镍和硫，而镍也可以通过镍合金碎片掉入熔融玻璃中引入。当玻璃受热时，这些原子会反应生成微小的硫化镍晶体。只有十分之一克的镍就可以在熔炉中形成多达50,000个晶体。

第7自然段

These crystals can exist in two forms: a dense form called the alpha phase, which is stable at high temperatures, and a less dense form called the beta phase, which is stable at room temperatures. The high temperatures used in the toughening process convert all the crystals to the dense, compact alpha form. But the subsequent cooling is so rapid that the crystals don’t have time to change back to the beta phase. This leaves unstable alpha crystals in the glass, primed like a coiled spring, ready to revert to the beta phase without warning.

这些晶体可以存在两种形态：一种是稳定在高温下的致密形式，称为α型；另一种是稳定在室温下的不致密形式，称为β型。钢化过程中使用的高温将所有晶体转化为致密紧凑的α相。但随后的快速冷却使晶体没有时间转变回β相。这样，在玻璃中留下了不稳定的α晶体，如同一个盘旋着的弹簧，随时准备回到β相而无法预测。

第8自然段

When this happens, the crystals expand by up to 4%. And if they are within the central, tensile region of the pane, the stresses this unleashes can shatter the whole sheet. The time that elapses before failure occurs is unpredictable. It could happen just months after manufacture, or decades later, although if the glass is heated – by sunlight, for example – the process is speeded up. Ironically, says Graham Dodd, of consulting engineers Arup in London, the oldest pane of toughened glass known to have failed due to nickel sulphide inclusions was in Pilkington’s glass research building in Lathom, Lancashire. The pane was 27 years old.

当发生这种情况时，晶体会膨胀高达4%。如果它们在板材的中央受力区域内，这种应力会使整个玻璃破裂。发生故障的时间是不可预测的。可能是制造后几个月，也可能是几十年之后，尽管如果玻璃受热（例如阳光照射），过程会加速。讽刺的是，伦敦Arup工程咨询公司的格雷厄姆·多德表示，由于硫化镍夹杂物导致钢化玻璃破裂的已知最老玻璃是在Pilkington的拉塞姆玻璃研究建筑物中。该玻璃已经使用了27年。

第9自然段

Data showing the scale of the nickel sulphide problem is almost impossible to find. The picture is made more complicated by the fact that these crystals occur in batches. So even if, on average, there is only one inclusion in 7 tonnes of glass, if you experience one nickel sulphide failure in your building, that probably means you’ve got a problem in more than one pane. Josie says that in the last decade he has worked on over 15 buildings with the number of failures into double figures.

关于硫化镍问题的数据几乎无法找到。事实上，这些晶体是成批出现的，使问题更加复杂。所以，即使平均每7吨玻璃中只有一个夹杂物，如果你的建筑物发生了一起硫化镍故障，那很可能意味着你的多块玻璃存在问题。乔西说，在过去的十年里，他已经处理过超过15栋建筑物的故障，并且其中多数硫化镍故障发生了。

第10自然段

One of the worst examples of this is Waterfront Place, which was completed in 1990. Over the following decade the 40-storey Brisbane block suffered a rash of failures. Eighty panes of its toughened glass shattered due to inclusions before experts were finally called in. John Barry, an expert in nickel sulphide contamination at the University of Queensland, analysed every glass pane in the building. Using a studio camera, a photographer went up in a cradle to take photos of every pane. These were scanned under a modified microfiche reader for signs of nickel sulphide crystals. ‘We discovered at least another 120 panes with potentially dangerous inclusions which were then replaced,’ says Barry. ‘It was a very expensive and time-consuming process that took around six months to complete.’ Though the project cost A$1.6 million (nearly ￡700,000), the alternative – re-cladding the entire building – would have cost ten times as much.

最糟糕的例子之一是Waterfront Place，该建筑于1990年完工。在接下来的十年中，这座布里斯班的40层大楼遭遇了一系列故障。在专家终于被召集过来之前，该建筑的80块钢化玻璃窗因含夹杂物而破裂。昆士兰大学的硫化镍污染专家约翰·巴里分析了建筑物中的每一片玻璃。摄影师借助一个吊篮上升拍摄了每一块玻璃的照片。这些照片在一个改装后的微缩胶片阅读器下扫描，以寻找硫化镍晶体的迹象。“我们发现还有至少另外120块可能存在危险夹杂物的玻璃需要更换，”巴里说。“这是一个非常昂贵和耗时的过程，大约花费了六个月的时间完成。”尽管项目成本达到了160万澳元（将近70万英镑），但另一种选择——重新给整个建筑物装饰玻璃——将会花费十倍的费用。