Mike Jones

Learning From Risk Control System
Failures
Mike Jones
MIKE JONES
Chief Consultant CRA
Industrial Process Assurance
• Process Safety/Technical Safety Consultant
• 43+ years experience in Industry/HSE/Consultancy
• Operations, Operations Management, Control Systems
• HSE Specialist Inspector (Process Safety)
MIKE JONES
HSE Experience
 Involved In about 40 investigations including:
 Gas explosions
 Fuel explosions (including a fatality)
 Dust explosions
 Deflagrations
 Fires
 Near asphyxiation
 Uncontrolled exothermic reactions
 Rapid degradation of containment
ABOUT YOU
How many of you are…
• Chemists
• Chemical Engineers
• Mechanical Engineers
• Safety Engineers
• Other Disciplines
• Regulators or ex Regulators
THIS EVENING’S TALK
We will examine three incidents
• Outline the circumstances leading up to the incident.
• Identify the immediate causes.
• Identify the immediate consequences.
• Examine the causes/failings.
• Identify the learning.
Any questions?
PITMACHIE GARAGE
What do you know about waste engine oil?
• Contains heavy metals
• Usually very dirty
• Combustible
• May contain 0.5% to 2.0% petrol
• Present in many garages…
PITMACHIE GARAGE
Events of the afternoon of Friday 18th June 2010
• A 23 year old experienced mechanic was cleaning up after
finishing the weeks work
• He was collecting old car parts (mainly brakes) and putting
them in drums
• He was someone who on this occasion didn’t follow advice
and training
• The first task involved cutting the tops off old drums so they
could be filled…
PITMACHIE GARAGE
Events of the afternoon of Friday 18th June 2010
Cutting the tops off old drums
PITMACHIE GARAGE
Events of the afternoon of Friday 18th June 2010
• One drum lid had been successfully removed using a
pneumatic hacksaw
• Colleagues complained that the saw was noisy
• The second drum lid was removed a different way…
PITMACHIE GARAGE
Events of the afternoon of Friday 18th June 2010
A thermic
lance was
used…
PITMACHIE GARAGE
Events of the afternoon of Friday 18th June 2010
PITMACHIE GARAGE
Investigation – Inverurie Police Station
PITMACHIE GARAGE
Investigation
• The drum lid had been forced off by the internal pressure in
the drum
• There had been an explosion
• What had fuelled the explosion?
• Why wasn’t there a subsequent fire?
PITMACHIE GARAGE
Investigation
• People can and do make mistakes when under peer pressure
• Rushing causes mistakes
• Even a tiny amount of petrol can kill you under the wrong
circumstances – how much?
• This was between 5 and 10ml.
• There are usually around two fatalities a year involving
exploding drums or small tanks.
• This information is given during apprenticeships
WASTE ENGINE OIL
ANY QUESTIONS?
METHANE
What do you know about methane?
• Gas at ambient conditions
• Highly flammable
 Flammable limits (~5-15% in air)
• Lower density (lighter) than air
 Rises rapidly
• Low minimum ignition energy
 MIE <0.2mJ
• Used at home…
LARKHALL, GAS EXPLOSION
Pre 1970
LARKHALL, GAS EXPLOSION
1970s - 1999
Medium Pressure (2barg)
Ductile Iron Gas Main
LARKHALL, GAS EXPLOSION
December 1999
LARKHALL, GAS EXPLOSION
22 December 1999 - 0530hrs
LARKHALL, GAS EXPLOSION
LARKHALL, GAS EXPLOSION
LARKHALL, GAS EXPLOSION
LARKHALL, GAS EXPLOSION
LARKHALL, GAS EXPLOSION
LARKHALL, GAS EXPLOSION
Immediate Causes
•
•
•
•
Medium pressure gas main failed.
Gas tracked into solumn of house.
Ignition of flammable natural gas-air mixture.
Ignition source not determined
 Switching on an appliance
 Lighting a cigarette
 Static
• Almost perfect gas/air mix
 Whole family of 4 died in the blast
 House obliterated
 Whole roof tiles up to 400m away
LARKHALL, GAS EXPLOSION
Failings
• Medium pressure gas main corroded.
• Ductile iron pipe thought to be polyethylene (from plan).
• Pipe replacement had not taken place.
• It was known that ductile iron corrodes unpredictably
due to carbon inclusions during manufacturing.
• Pipe had been in place for 25+ years.
• Use of land had changed over time.
• Rubble under houses was capped with clay.
LARKHALL, GAS EXPLOSION
Learning
• Always try to recognise change,
No matter how slow it may seem.
• Always try to question change….
No matter how insignificant it may seem.
LARKHALL, GAS EXPLOSION
Any Questions?
BITUMEN
What do you know about bitumen?
• Residues/Heavy ends from crude oil processing
• Highly viscous fluid, may be solid at ambient conditions
• Combustible, supports fire
• Has to be processed at high temperatures (c.300C) to
become fluid enough for handling..
• Widely used on roads…
NYNAS REFINERY, DUNDEE
Bitumen Production
KERO
CRUDE
NAPHTHA
ATM
HFO
VAC
J303
BITUMEN
NYNAS REFINERY, DUNDEE
Bitumen Production
• Heavy Crude feed (e.g. Venezuelan) to bulk storage
• Crude transfer (50 -100C)
• Atmospheric Distillation to remove light ends (Naphtha)
• Reduced Crude transfer (300C)
• Vacuum distillation to penetration spec.
• Some blended into emulsions for cold processing.
• Bulk blending and distribution.
NYNAS REFINERY, DUNDEE
J303 Reduced Crude Feed Pumps A & B
NYNAS REFINERY, DUNDEE
01:35a.m. on 10th November 2010
• Plant operating at 900 t.p.d.
• External call received to report smoke/steam on Nynas
plant.
• Operator investigates area around J303 pumps
 Hears “crackling” sound.
 Sees liquid between pumps
 Does not see smoke
 Decides not to change over pumps and walks away
 Sees a blue flame and fireball
• Seal failure on pump diagnosed
NYNAS REFINERY, DUNDEE
J303 Reduced Crude Feed Pumps A & B
NYNAS REFINERY, DUNDEE
Incident
• Plant tripping
• Tayside Fire & Rescue Service called and on site
• Fire alarm activates via smoke detector
• Alarm sounders silenced
• ESD valve manually shut
• No one injured
NYNAS REFINERY, DUNDEE
Incident - Foam System
• Foam pouring system did not automatically activate
• Foam pouring system failed to operate when manually
activated
• Diesel fire pump manually started, still no foam
• Back up foam supply from containers used by TSFR to
address incident
NYNAS REFINERY, DUNDEE
Post Incident – Foam System
• Typical zoned foam pouring system fed by diesel pump
• Loss of air pressure (quartzoid bulbs) activated system
• Six monthly external maintenance by TYCO
• MOU by pass found open
• MOU by-pass now locked closed
NYNAS REFINERY, DUNDEE
Post Incident – Foam System
Single point of failure
Disabled whole plant system
MOU
MOU By-pass
NYNAS REFINERY, DUNDEE
Post Incident – Fire suppression
J303 Reduced Crude Feed Pumps A & B
NYNAS REFINERY, DUNDEE
Post Incident – Fire suppression
• How can fire be suppressed at these pumps?
• Steam snuffing system fitted
• Used a convenient steam supply nearby
• Not seen as a plant modification
• No risk assessment
NYNAS REFINERY, DUNDEE
Post Incident – Steam snuffing system
What are the risks here?
NYNAS REFINERY, DUNDEE
Post Incident – Steam snuffing system risks
• High process temperature (>300C)
• Potential for condensate in steam – no traps fitted
• Condensate in process could cause internal explosion
• Potential for injury/fatality of operator (in area)…
• System isolated (advice)
NYNAS REFINERY, DUNDEE
Incident – J303 pumps
• Pump changeover manual
• Not identified as a particular risk
• System in excess of 300C during changeover
• Only a single mechanical seal on pumps
• Risk?....
• Revised procedures and assessment
ANY QUESTIONS?