Archives For Common cause failures


JAL JA829J Fire (Image Source: Stephan Savoia AP Photo)

Boeing’s Dreamliner program runs into trouble with lithium ion batteries

Lithium batteries performance in providing lightweight, low volume power storage has made them a ubiquitous part of modern consumer life. And high power density also makes them attractive in applications, such as aerospace, where weight and space are at a premium. Unfortunately lithium batteries are also very unforgiving if operated outside their safe operating envelope and can fail in a spectacularly energetic fashion called a thermal runaway (1), as occurred in the recent JAL and ANA 787 incidents.

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Buncefield Tank on Fire (Image Source: Royal Chiltern Air Support Unit)

Why sometimes simpler is better in safety engineering.

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Resilience and common cause considered in the wake of hurricane Sandy

One of the fairly obvious lessons from Hurricane Sandy is the vulnerability of underground infrastructure such as subways, road tunnels and below grade service equipment to flooding events.

The New York City subway system is 108 years old, but it has never faced a disaster as devastating as what we experienced last night”

NYC transport director Joseph Lhota

Yet despite the obviousness of the risk we still insist on placing such services and infrastructure below grade level. Considering actual rises in mean sea level, e.g a 1 foot increase at Battery Park NYC since 1900, and those projected to occur this century perhaps now is the time to recompute the likelihood and risk of storm surges overtopping defensive barriers.

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Warsaw A320 Accident (Image Source: Unknown)

One of the questions that we should ask whenever an accident occurs is whether we could have identified the causes during design? And if we didn’t, is there a flaw in our safety process?

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In an article published in the online magazine Spectrum Eliza Strickland has charted the first 24 hours at Fukushima. A sobering description of the difficulty of the task facing the operators in the wake of the tsunami.

Her article identified a number of specific lessons about nuclear plant design, so in this post I thought I’d look at whether more general lessons for high consequence system design could be inferred in turn from her list.

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Did the designers of the japanese seawalls consider all the factors?

In an eerie parallel with the Blayais nuclear power plant flooding incident it appears that the designers of tsunami protection for the Japanese coastal cities and infrastructure hit by the 2011 earthquake did not consider all the combinations of environmental factors that go to set the height of a tsunami.

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For those interested the interim report by Mike Weightman, the UK’s Inspector of Nuclear Installations, on lessons from Fukushima has been released.

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