Flawed Beauty: The Problem With Toughened Glass — IELTS Reading Answers

Brian Waldron

“But he insists that cases are few and far between. 'It's a very rare phenomenon,' he says”

Waldron insists 'cases are few and far between' and calls nickel sulphide failure 'a very rare phenomenon' — option G.

Trevor Ford

“'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.'”

Ford says 'what you hear is only the tip of the iceberg' because 'no-one wants bad press', implying publicity is suppressed — option A.

Graham Dodd

“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”

Dodd cites 'the oldest pane of toughened glass known to have failed', aged 27 years — the most extreme delayed failure, option H.

John Barry

“John Barry, an expert in nickel sulphide contamination at the University of Queensland, analysed every glass pane in the building”

Barry 'analysed every glass pane in the building', matching option C's close examination of all the glass.

“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”

The gap needs the adjective for shards: toughened glass breaks into tiny cubes rather than 'large, razor-sharp shards'.

“a large pane of toughened glass in the roof of a shopping centre at Bishops Walk shattered without warning and fell from its frame”

The gap needs the adverb for the Bishops Walk failure: the pane 'shattered without warning', so it failed unexpectedly.

“It is made by heating a sheet of ordinary glass to about 620°C to soften it slightly, allowing its structure to expand, and then cooling it rapidly with jets of cold air”

The gap needs how cooling happens: glass is cooled 'rapidly with jets of cold air', meaning quickly.

“This causes the outer layer of the pane to contract and solidify before the interior”

The gap needs what heat does to the structure: heating softens the glass, 'allowing its structure to expand', before rapid cooling.

“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”

The gap needs the adjective for sun-heated glass: 'if the glass is heated — by sunlight, for example — the process is speeded up'.

“'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 Others disagree”

The gap needs 'agreed': Waldron calls the failure 'a very rare phenomenon', but the text immediately adds 'others disagree', so no consensus exists.

Little doubt was expressed about the reason for the Bishops Walk accident.

“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”

Experts at Pilkington found 'minute crystals of nickel sulphide trapped inside the glass had almost certainly caused the failure', so doubt was minimal.

Toughened glass has the same appearance as ordinary glass.

“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”

The passage contrasts strength and breakage but never says toughened glass looks the same as ordinary glass.

There is plenty of documented evidence available about the incidence of nickel sulphide failure.

“Data showing the scale of the nickel sulphide problem is almost impossible to find”

'Data showing the scale of the nickel sulphide problem is almost impossible to find', so evidence is scarce, not plentiful.