The investigation into the cause of the fire - Stuart ... Park Investigation... · Investigation of...

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?