the investigation into the cause of the fire - stuart ... park investigation... · investigation of...
TRANSCRIPT
DR J H BURGOYNE AND PARTNERS LLPFORENSIC SERVICES
ROSEPARK CARE HOME
Investigation of the cause of the Fire on 31 January 2004
POLICE CONTACTED BURGOYNES
• Initial contact, evening of Saturday 31 January 2004Could we assist with fire alarm system memory?
• Initial site visit, 14:00 hours of 1 February 2004Look at equipment and provide advice
OVERVIEW• Fire in a cupboard• Large number of fatalities• Recent changes to the fire alarm system• Need to determine cause of fire and why so
many deaths occurred
INITIAL AIMS• Ascertain if the fire alarm panel had a memory• To interrogate any fire alarm system memory• Time of the essence – system memory loss
REQUIRED INFORMATION• Which alarm activated first?• When was the first alarm activation?• When and in what order did subsequent alarm
activations occur?
THE PANEL DID NOT HAVE A MEMORY
• Concerns about whether the system gave the correct alarm, leading to delays in detection
• Were any problems caused by the fire alarm panel change?
SYSTEM CHECKING• Burgoynes managed the process and
ensured that the information gathering met appropriate standards
• Chubb undertook the actual checks, under Burgoyne’s guidance.
THE FIRE ALARM SYSTEM• The panel worked correctly• The surviving detectors and sounders
worked correctly• The fire alarm zones crossed fire
boundaries
Zone
3
Zone
2
Zone
1
Dining area,kitchens and
lounge
Entr
ance
foye
r
Gamescupboard
Lift
Fire alarmpanel
Offices Accommodation
Accommodation
Accommodation
Acco
mm
odat
ion
Acco
mm
odat
ion
Cor
ridor
Area
of d
irect
fire
atta
ck
CorridorCorridor Area of directfire attack
Fire
Smoke first seen byMr Norton
Stairwell
Zone
3
Zone
2
Zone
1
Dining area,kitchens and
lounge
Entr
ance
foye
r
Gamescupboard
Lift
Fire alarmpanel
Offices Accommodation
Accommodation
Accommodation
Acco
mm
odat
ion
Acco
mm
odat
ion
Cor
ridor
Area
of d
irect
fire
atta
ck
CorridorCorridor Area of directfire attack
Fire
Smoke first seen byMr Norton
Stairwell
MAIN CONCERNSWITH THE FIRE ALARM SYSTEM
• Zoning crossed fire barriers• Poor zone descriptions• No mimic diagram as BS 5839: Part 1, 1988• Zones not tested when panel was replaced• Staff unfamiliar with the replacement panel• Sounders too quiet
FIRE INVESTIGATION• Police decided to use multi-agency approach• Police Officers, forensic scientists /
photographers• Fire Service investigators• Private sector (Burgoynes)• HSE
BENEFITS• Police forensic facilities and evidence
gathering• Fire Service experience fire fighting and
development• Private sector experience in science and
engineering• HSE labs and expertise
FIRE INVESTIGATION• Area of origin• Cause of fire• Smoke spread• Lessons learned
ORIGINEvidence gathering
• Observations – photograph and sketch• Reconstruction – replace items which have
been disturbed• Excavations – sift through the debris• Witness accounts
ORIGINItems that were considered
• Areas of greatest charring - duration• Directional char patterns - spread• Available fuel types and quantities – degree of
damage
ORIGINItems that were considered (cont)
• Availability of air / drafts• Mechanisms of fire spread (explosions)• Effects of electrical arcing activity• Witness accounts• Alarm logs (none)• CCTV
ORIGINDetermining the area of origin
• Construct hypotheses that fit the evidence• Test each hypothesis• Identify which hypotheses stand up to scrutiny• Reject those that do not• Led us to the cupboard
The cupboard
ORIGINThe conclusions
• The fire started in the cupboard• The fire probably started to the left hand side of
the cupboard• Electrical arcing evidence was consistent with
the fire starting at or below about half way up the cupboard
CAUSEDetermining the cause
• Identify potential sources of ignition• Construct hypotheses that fit the evidence• Test each hypothesis• Identify which hypotheses stand up to scrutiny• Reject those that do not
CAUSEPotential ignition sources
• Deliberate • Cigarettes /smoking materials• Electrical mechanisms• Other undeclared / exotica
CAUSEEvaluation of ignition sources
• No evidence of deliberate / did not fit evidence• Smokers present but did not fit evidence• No remains of other undeclared / exotica, and / or
did not fit evidence• Significant electrical evidence – arcing / damage
patterns
The distribution board
CAUSEEvaluation of electrical evidence
• No evidence outside the distribution board • One circuit breaker was different – added late• Arcing occurred at a “busbar” (main conductor)• Arcing occurred at a cable to the laundry
The circuit breaker
The circuit breaker
The circuit breaker fixed contact
The circuit breaker moving contact
CAUSEConclusions re the breaker
• It was a different make to the others• The materials reacted differently to fire• It complied with relevant standards• It was incorrectly installed • The error was not detected or ignored
Arcing at the busbar
Arcing at the cable V
CAUSEInvestigation of the arcing
• Arcing can cause fires• Fires can cause arcing• Chicken or egg?
Electrical sequence logic
CutoutFuse
NeutralLink Earth
Meter
Fusebox or consumer unit
Socket
Socket
Socket
32 6
ON/OFF
RCD
switch switchAppliance
Plug&
FuseSocket
1
2
3
4
CAUSEConclusions re the arcing
• Busbar arcing did not precede that at the cable• Cable arcing preceded that at the busbar• Any circuit breaker electrical trip must have
occurred after the cable arced
THE ARCING AT THE CABLE WAS 1ST
CAUSEEvidence re the cable that arced
• The sheath had been cut back too far• The edge of the penetration was not protected• The core insulation was probably damaged on
installation• The cable was incorrectly installed • The error was not detected
CAUSEThe conclusions
• Arcing activity occurred at the cable• Incendive sparks were ejected• Combustible materials were ignited as a result
of the arcing activity
SMOKE SPREADThe concerns
• Deaths were attributable to smoke inhalation• Smoke spread further than might have been
expected
SMOKE SPREADPertinent factors include
• Discovery of the fire• Actions following discovery• The construction of the building
SPREAD• From the cupboard• Along Zone 3 corridor• Into bedrooms• “Through” a fire door to Zone 2• Along ductwork between Zone 3 and 2• Into and throughout the roof space
SPREAD• Aerosols in the cupboard “blew” doors open• Bedroom doors open / did not have closers• A fire door was blown open and “stuck”• Ductwork did not have smoke dampers• Roof space fire barriers compromised
VERIFICATION• Fire tests of cupboard and associated corridor• Simulating electrical faults• Checking fire resistance• Smoke spread tests• Aerosol explosion tests
LESSONSEquipment
• Electrical installation by qualified staff• Fire zones to match fire barriers• Ventilation is not to compromise fire barriers• Clear fire alarm mimics / zone descriptions• Fire alarm panel memories are advantageous
LESSONSOrganisation
• Inspection and test per IET guidelines BS7671• Inspection and test of fire alarm systems to
include zone checks / test after changes• Storage of aerosols to be appropriate• Staff training to take account of fire alarm
system changes
Any Questions?