Learning from - PowerPoint Presentation

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Learning from ECS Failures:  What can go wrong?

Fall 2012

Lecture # XXSlide2

Learning From The PastTo engineer is human!To err is human!

To err as an engineer can be dangerous!Slide3

What Makes A Failure Into A Disaster?Public

perception of

risk

e.g. In 2008 :

Total

Auto-Related Deaths: 34,017

Total Train-Related Deaths: 800Total Bicycle-Related Deaths: 716Total Airline-Related deaths: 0Can be converted to accidents per miles traveled and auto is still highestYet the public perception of the risk associated with air travel is often much higher than that for trains and certainly for bicycles. Two reasonsthe large loss of life (and associated wide spread news reporting) resulting from a single air crashair passenger's lack of control over their environment in the case of air or, to a lesser degree, rail accidents. Both of these reasons results in increased fear, and hence a higher degree of perceived riskSlide4

A Weird Disaster as a first example

Boston Molasses Disaster

aka Boston

Molassacre

Molasses was standard sweetener and fermented to produce rum and ethyl alcohol

January

15, 1919 in Boston Massachusetts at Purity Distilling Company facilityLarge (50 foot tall) molasses storage tank burst, and a wave of molasses rushed through the streets at an estimated 35 mph21 Killed and 150 injured8 to 15 ft wave of molasses moving at 35 mphTemperature had risen from 2 degrees to 40 degrees over 24 hours87,000 hours to cleanupLocal residents brought class action lawsuit and company eventually paid out $600,000 in out-of-court settlements (at least $10.7 million in 2012 dollars)Contributing Factors

The

tank was constructed poorly

Tank had only been filled to capacity 8 times since it was built and never in cold weather

Neither of these conditions had been design tested

Basic safety tests were neglected

Tank was painted brown because it leaked so badly (to disguise the leaking molasses) due to poor constructionSlide5

A video introduction:Why Study Failures?Early Engineering Disasters

Software Flaws

HaitiSlide6

Primary Causes of ECS Disasters human factors

e

thical

a

ccidents

design

flawsmaterials failures extreme conditions or environmentscombinations of these reasons perhaps the most important and overlookedSlide7

Challenger Space Shuttle

January 28, 1986 Cape Canaveral, Florida

73 seconds into flight, exploded killing all seven astronauts

What went wrong?

Two solid rocket boosters (SRB) contain the fuel that lifts the shuttle into space

Each SRB has four sections and two large rubber rings (called O-rings) close any gaps between sections

One of the O-rings didn’t seal and fuel supply explodedLooking backO-rings had been used over and overCold makes the O-rings brittleWhen engineers recommended postponing launchManagement asked “are you sure the rings will fail?”Should have asked “are you sure the rings will NOT fail?”Looking forward400 improvements to shuttle programIn 2003, Space Shuttle Columbia broke apart on re-entry because of another engineering failure and all seven astronauts diedSlide8

Hyatt Regency Hotel

July 17, 1981 Kansas City, Missouri

Fourth floor walkway collapsed killing 114 people and injuring 200

What happened?

Hanging

Walkways on second, third, and fourth floor overlooked lobby

Metal Rod that held the fourth floor walkway to the ceiling had failedLooking BackOriginal engineering designs called for walkways to be attached to ceiling by long rodsDue to construction challenges, builder suggested a change…attach fourth floor to ceiling with shorter rods and then attach second floor walkway to fourth floor walkwayChange approved via phone without detailed check of safety and load capacity of redesignIf you and a friend are hanging on to a rope versus you are hanging on to the rope and your friend is hanging onto you…eventually you get tired and both of you crash to the groundLooking ForwardEngineer of Record & Engineer who approved the change lost their licensesEngineering profession changed its proceduresEngineer of record is now totally responsible for the structural integrity of project

Written approval required for all contractor modificationsSlide9

Patriot Missile System1991 Saudi Arabia

American Army Barracks destroyed

What went wrong?

First Gulf War

Patriot Missile system failed to intercept an incoming Iraqi Scud missile

Missile hit an Army Barracks

28 soldiers died and 100 injuredLooking backA software rounding error incorrectly calculated the time, causing the Patriot system to ignore the incoming Scud missile Looking forwardReduction in assumptions to avoid anomalies Duplicated solutions by different algorithmsSlide10

Tacoma Narrows BridgeNovember 7, 1940 Tacoma, Washington

4 months after opening the bridge collapsed

What went wrong?

42 mph winds caused the bridge to sway

Cables on the west side snapped

Only casualty was Tubby the dog who was trapped in a car

Looking backDesign used a solid steel girder instead of stiffening trusses to achieve a slender, flexible bridge – pushing the limits of engineeringNicknamed Galloping Gertie due to swaying and rollingDrivers would lose sight of cars ahead of themEngineer neglected aerodynamicsLooking forwardWind tunnels used to test bridge design before construction startsSlide11

South Fork DamMay 31, 1889 Johnstown, Pennsylvania

Dam broke killing more than 2000

What went wrong?

Embankment dam made of mounded up earth, boulders, & clay

Ruptured at 3:10pm and water hit town at 4:07pm with

40-foot

waves and a speed of 40mphWater coated with oil from the waste caught fireLooking backCulverts valves were shut off so water was not being dischargedSouth Fork Hunting & Fishing Club bought the dam and built a trap across the dam’s spillway to keep fish in the lake. The trap became clogged with debris.Dam had an unrepaired sag that weakened the structureLooking forwardSlide12

Chernobyl

April 26, 1986 Ukraine

Reactor No. 4 exploded killing 31 people outright

What happened?

Plant managers were running an experiment to see if a winding-down turbine could generate enough electricity to last for the forty to fifty seconds it would take for back-up diesel generators to take over

They cut the power and ignored warning lights in hope of completing the experiment. Reactor went out of control within seconds and two explosions ripped the roof off the reactor, spewing radioactive material

Looking BackIt took firefighters in helicopters two weeks to douse the reactor failureIt took six months to entomb the reactor in lead and concreteComputer controlled disaster avoidance measures were overriddenLooking ForwardCulture of safetySpecific guidelines for all operations including testingSlide13

Hartford Coliseum Collapse

January 18, 1978 Hartford, Connecticut

Roof collapsed-0

What happened?

5 years after opening, roof collapsed due to heaviest snowstorm in 5 years

Happened in early hours of the morning so venue was unoccupied (but hours earlier held 500 spectators)

Looking BackDesign of the innovative roof space truss was done using CAD softwareDead loads were underestimated by more than 20% by the CAD software. The computer model assumed all of the top chords were laterally braced, but in fact only the interior frame met the criteria because of the diagonal bracing.Multiple assumptions built into the CAD software were not validLooking ForwardDesigners may be hired to preform traditional services, but courts may still find them responsible because they are licensed professionals who are liable for public safety

Checks and Balances for human and computer generated designsSlide14

BhopalDecember 2, 1984 Bhopal, India

44 tons of MIC escaped from Union Carbide plant killing 7000 people

What happened?

Water leaked into storage tank for methyl

isocyanate

(MIC) which reacts with waterMIC reacted violently with water causing the tanks to crackLooking BackRefrigeration unit used to keep MIC cool (and less likely to overheat and expand if contaminated) had been turned off five months earlierA storage tank for excess MIC was already fullA gas scrubber, designed to neutralize escaping gas, didn’t workThe flare tower, which burned off escaping MIC from the gas scrubber, wasn’t workingSpray from fire truck hoses couldn’t reach the escaping gas fumesLooking ForwardChanges worldwide to regulation of chemicalsIn US, Community Right To Know requires disclosure of all chemical storage and transportSlide15

Apollo 13

December 2, 1984 Cape

Canaveral, Florida

liquid oxygen tank exploded causing loss of fuel cells

What happened?

56 hours into flight liquid oxygen tank exploded

Without fuel cells, supply of electricity, light & water plummetedTo save power, crew moved from Command Module into smaller Lunar Module 90 hours needed to get back to earth but LM not designed to sustain 3 astronautsCarbon Dioxide levels climbed due to cramped quarters causing dirty filterCM & LM filters not same but duct tape, cardboard, plastic bags used to retrofit Looking BackTank originally designed for Apollo 10 mission but deemed safe for Apollo 13Apollo 13 rewired and old tank ran on lower voltage than the newly rewired spacecraftPre-launch testing damaged wiring insulation & fans used during mission caused spark

Insulation caught fire & BANG

Looking Forward

Oxygen tanks modified

Third liquid oxygen tank added

Backup battery installedSlide16

Homework #XXResearch ECS Disasters

Create a single page report (double spaced) that lists and describes three engineering disasters from three different engineering disciplines

Cannot use any of the examples used in class lecture

At least one must be from your specific area of study

Submit via eLearning

Due

one week from todaySlide17

Further Readinghttp://www.nytimes.com/2010/07/20/science/20lesson.html?pagewanted=all

http://engineeringfailures.org

/Slide18
Slide19

CreditsFantastic Feats & FailuresModern Marvels, History ChannelEmbedded videos and websites