1 Lucky Barriers • Update of slide show sent out as an issue of “The Firebird Forum” • Show it to your rooticians and their stakeholders, e.g., management, CARB. 010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Tff V11 N01 Lucky Barriers Updated 2010 03 01
May 22, 2015
Entertaining and educational slideshow on Lucky Barriers.
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1
Lucky Barriers
• Update of slide show sent out as an issue of “The Firebird Forum”
• Show it to your rooticians and their stakeholders, e.g., management, CARB.
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
2
Lucky Barrier
Anything that does or did protect something worth protecting, but is so fragile as to be "lucky."
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
4
PositiveControl Of Tools
Pre-job BriefLanyards
ForTools
RestrainingLip on
Scaffold Deck
SituationalAwareness
Preventing Work
Under Scaffold
(Luck)HardHat
First AidAssistance
MedicalAssistance
Ineffective: See actual hazards.
Ineffective: Worker set
hammer down.
Ineffective: Hammer
not tethered.
Ineffective: Gap in
restraining lip.
Ineffective: Worker A
Kicks Hammer Off Deck..
Ineffective:Worker B
UnderScaffold
EffectiveBarrier:HammerMisses
Worker B
Not Challenged
Not Challenged
Not Challenged
??
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Ineffective: See actual hazards.
Ineffective: Worker set
hammer down.
5
Four Types Of Factors
VulnerabilityFactors
ExacerbatingFactors
Quality &Safety Impact
MitigatingFactors
TriggeringFactors
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
The Lucky Barrier
comes in here!!
6© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Eight Questions For Insight
Quality & Safety Impact What were the event consequences?
What was the event significance?
Vulnerability What set us up for the event?
What triggered the event?
What made the event as bad as it was?
What kept it from being a lot worse?
Learning: What should be learned from the event?
Doing: What should be done about it?
Consummation
Exacerbation
Mitigation
Corrective Action (closeout)
The Lucky Barrier
comes in here!!
7
8
Lucky Barrier Case
• Submarine erroneously loads oxygen into potable water (PW) connection. PW vents inboard. (PW and O2 both color coded blue.)
• Oxygen “enriches” submarine atmosphere.• If continued could lead to widespread fire.• Sailor inspecting trunk into which potable water
vents notices his cigarette burning too well.• Sailor alerts the rest of the watch and load is
terminated.
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Lucky Barrier
9
Lucky Barrier Case
• Operator attending to Motor Control Center.
• Operator needs to have Control Room start the equipment.
• No radio signal in front of MCC.• Operator moves to where signal is
better.• MCC explodes when CR starts
equipment.• Major arc flash near MCC.• Moving averted injury/fatality.
Luck
y B
arrie
r
10© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
11
Lucky Barrier Case
• Wrong valve identified for work.• Grinder cut into pressurized hydrogen line.• Grinder sparks ignite “Bunsen burner.”• Fire averts filling building with hydrogen.• No flammable material in Line-of-Fire.
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Lucky Barrier
12
Lucky Barrier Case
• Hoist Falls from Monorail.
• Normally occupied area.• Not occupied (lucky
barrier).• No personnel harm.• Potential fatality averted.
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Lucky Barrier
13
Lucky Barrier Case
• Pressurized Water Reactor.
• PORV sticks open.
• Pressurizer level pegs.
• Operators turn off safety injection.
• Not enough decay heat to melt fuel.
• Precursor to TMI-2 meltdown.
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Lucky Barrier
14
Lucky Barrier Case
• Electrical Equipment Room (EER) Flooding.
• Operators do not know it.• Security Officer randomly enters EER.• Security Officer gets wet feet.• Security Officer notifies Control Room.• Source of flooding isolated.• Severe equipment damage averted.
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Lucky Barrier
15
Lucky Barrier Case
• Scaffold built in line-of-fire of MSIV operator stroke.
• Routine test impacts scaffold w/o damaging valve operator.
• No personnel on scaffold (potential fatality averted).
• Interference not sufficient to degrade valve safety function (potential risk increase averted).
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
Lucky Barrier
16
Lucky Barrier Case
• U. S. Airways Flight 1549 engines strike Canada Geese
• Has certain altitude and speed• No airports available• Pilot is glider expert• Passes 300’ above GW Bridge• Ditches in calm Hudson River• Does not hit ship traffic• Vessels nearby remove passengers and crew
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
5 Lucky Barriers
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Other Lucky Barrier Cases
• Davis-Besse 2002– LB=Leakage at Oconee
• NWA 253 (“Undie Bomber”)– LB= Bomb did not detonate
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Lucky Barrier Facts
• Lucky Barriers tend to be inconsistent and unreliable.
• Without the Lucky Barriers near misses would be Real McCoys.
• Some of the most important corrective actions emerge from probing Lucky Barriers.
• Important missed opportunities to prevent future consequences come from ignoring Lucky Barriers.
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
20
Lucky Barrier Lessons to be Learned
• Be sure you understand the factors that resulted in the nature, the magnitude, the location, and the timing of the most important consequences.
• OBTW: Consequences can be actual, expected, or potential.
• For every actual consequence one of the factors was a mitigating factor.
• For every potential consequence one of the factors was a preventive factor.
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
21
Lucky Barrier Lessons to be Learned
• The Lucky Barriers will be among the preventive factors and mitigating factors.
• Assess what the robustness of each Lucky Barrier was.
• Assess what the consequences would have been without the Lucky Barriers, individually and jointly.
• A Lucky Barrier should be interpreted as a “shot across the bow.”
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
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Lucky Barrier(LB) Action Items
1. Discuss the LBs in your Executive Summary.2. Put the LBs in your Comparative TimeLine©.3. Describe the LBs in your Narrative.4. Put the LBs in your Barrier Analysis Matrix.5. Put the LBs in your Factor Tree.6. Put the LBs in your Event and Causal Factor Chart.7. Pursue the Extent of Condition of other LBs. 8. Have Corrective Actions that make LBs unnecessary.9. Adopt LBs as a standard Line of Inquiry (like LOW,
Flawed Barriers, Error Precursors, etc.)
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
23
Oh, by the way.
• If you can take a picture of your Lucky Barrier, do so.
• Use it in your RCAR.
The Sailor who noticed the high oxygen.© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
24
Send your favorite Lucky Barrier action items and pictures to
25
Lucky Barriers Bottom Line
1. Luck is not a robust barrier.2. Luck is an information-rich barrier.3. Eliminating the need for LBs is a “no
brainer.”
© 2010, William R. Corcoran, NSRC Corp., 860-285-8779, [email protected]
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