Case Histories

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case Histories

On 18 November 1987, a serious fire occurred at the King’s Cross under- ground railway station in London, UK; 31 people died as a result of this fire. A Public Investigation into the causes and circumstances of the fire, conducted by Desmond Fennell OBE QC, sat for 91 days. A detailed report of this Inves- tigation has been published’.

Although an underground railway system is not in any sense a part of the ‘process industries’, the loss prevention aspects of this incident and its attendant circumstances make it an appropriate case study for Journal of Loss Preven- tion in the Process Industries.

King’s Cross underground station is the busiest and most complex on the network, and comprises the subsurface Circle Line platforms and three sets of deep level tube line platforms (Piccadil- ly, Victoria and Northern). The fire began at approximately 19.25, in a layer of grease on the support mechanism beneath an escalator (40 m long, rising at 30” to the horizontal) that connected the station ticket hall to the Piccadilly Line platforms. By 19.30, the fire, which was about half way up the escala- tor, was visible from the travelling side of the escalator through the narrow gap between the moving staircase and the stationary components of the escalator. A passenger stopped the escalator and reported the presence of the fire to a member of the station staff. A British Transport policeman, who was in the ticket hall at the time (by chance, rather than on an assigned duty), reported the fire by radio to BTP headquarters.

The steps of the moving staircase and the surrounds of the escalator were made from wood. At about 19.32, the developing fire beneath the escalator spread through the gap to the wood surfaces on the passenger side of the escalator; the right hand balustrade ignited and flames spread slowly up this balustrade and across the steps. By 19.43, the visible fire involved about

The King’s Cross fire

1-2 m of the right hand balustrade, with the flames at about handrail height, and flames had spread across most of the width of the steps. At about 19.43, the left hand balustrade ignited and the fire then began to develop much more rapidly, as a coherent, low lying body of flame in the escalator trench. In a period of about 45 s, around 19.45, the flames reached the upper part of the escalator and a jet of flame shot into the ticket hall and impinged on the ceiling.

Until about 19.43, the fire was relatively smoke free. However, during the period of rapid development, mate- rials other than the wood of the escala- tor began to be involved and some increases in smoke emission occurred. The entry of the jet of flame into the ticket hall was followed very shortly afterwards by a massive increase in smoke flow; this thick black flow of smoke swept through the ticket hall and along all the passageways connecting the ticket hall to street level access points. Many people were overtaken by this flow of hot smoke and had to make their escape under very difficult cir- cumstances. As mentioned earlier, 31 people died as a result of the fire, in the ticket hall and connecting passageways.

This description raises two immedi- ate questions with respect to the loss of life in this fire:

l why did the fire spread so rapidly in the period around 19.45?

l why were there still people at risk in the ticket hall and connecting pas- sageways at 19.45, i.e. 15 min after the notification of the outbreak of fire?

The first question was addressed by a detailed scientific investigation of the fire; the results were reported in a seminar organised by the Institution of Mechanical Engineers*-5. This inves- tigation showed that once the fire was burning across the width of the escala- tor and involving both balustrades, an

aerodynamic effect kept the flames low in the sloping escalator trench rather than allowing the flames to rise from the trench. This ‘trench effect’ conserved the heat of the fire within the trench and extended the flames along it, thereby greatly enhancing heat transfer rates to unburnt wood ahead of the fire and leading to a very rapid increase in rate of flame spread. Model experiments on a one third scale at the Health & Safety Executive (HSE) Explosion and Flame Laboratory gave flame spread rates and flame appearances very similar to those derived from eyewitness accounts of the actual fire. A video record of the scientific investigation is available from the HSE, Buxton, Derbyshire.

Any answer to the second question must take account of many factors. The notification of the fire at 19.30 pro- duced several actions:

the affected escalator was stopped and passenger flows were diverted to the flight of escalators between the ticket hall and the Victoria Line platforms, via connecting passage- ways and stairs; ticket office staff contacted a station supervisor, who came to the escala- tor and entered its machinery room to inspect the fire; the London Fire Brigade was alerted via British Transport Police head- quarters, with the first appliances arriving at 19.43. Firemen entered the station to ascertain the location of the fire and several were over- taken by the smoke flow at 19.45: a Station Officer was one of the fatali- ties; London Underground (LUL) con- trollers were notified of the fire by an indirect route, and by 19.42-19.44 trains passing through the station were notified to ‘non-stop’, i.e. to pass through the station at slow speed without stopping to discharge passengers, but with the ability to

332 J. Loss Prev. Process Ind., 1990, Vol3, July

Case Histories

stop to evacuate passengers from the station if signalled to do so.

The overall effect of these actions was that passengers entered the station un- checked from street level until 19.45 and passengers alighted from trains at platform level until 19.42-19.44 [de- Pending on the line). Passenger flows between tube platforms and ticket hall were therefore maintained, although British Transport Police were trying to evacuate the lower levels. The evacua- tion route up the Victoria Line escalator led into the ticket hall, so that when Rashover from the Piccadilly Line esca- lator to the ticket hall occurred at 19.45, people using that route were trapped by flames and smoke.

Many issues relating to loss preven- tion arise from this incident.

Fire statistics There was no central collation of fire statistics relating to the London Under- ground system. Different sets of in- formation existed, e.g. on lift and esca- lator fires or electrical fires, but these were not systematically drawn together and analysed to give a total picture. The prevalent attitude seemed to be that small fires were inevitable but fires in stations with fatal consequences were impossible. The basic data to show that life threatening fires had a non- negligible probability existed, but the absence of systematic analysis obscured this fact.

investigation of specific fires Several fires on the system had been the subject of quite thorough internal inves- tigations, and reports containing useful recommendations had been issued. However, the recommendations were often repetitiv-there seemed to be no mechanism for recognising the common features of these incidents and carrying strong recommendations based on a pattern of incidents through to the highest management levels. The Fen- nell report gave details of six serious escalator fires, with many features in common with the earlier stages of the King’s Cross fire, for the period 22 December 1984 to 30 August 1987. In addition, there was a se&us fire in a contractors storage area of Oxford Cir- cus station on 23 November 1984. The Oxford Circus fire was the subject of a Task Force with high level management

involvement. On this basis alone, fires with an adverse effect on means of escape were occurring at a frequency of about 2 per year.

Means of escape The Oxford Circus fire in particular identified problems with means of escape in the event of a station fire. As a result, LUL surveyed stations to identify possible emergency escape routes for use if a station fire prevented use of the main passageways. Ironically, King’s Cross station had an alternative route in the shape of a completely independent tunnel from the tube line platforms to King’s Cross BR Thameslink station (then called Mid- land City station). Because of construc- tion work at this BR station, the inde- pendent tunnel was closed at 19.00 on the evening in question, and it was not available for emergency use.

LUL set considerable store by the ability to evacuate stations by train. On the evening of 18 November, many passengers were evacuated by train from 19.44 onwards but the complexity of the station and the delays in activat- ing this procedure led British Transport Police to adopt the only route apparent- ly available to them, as described ear- lier. Evacuation by train does involve the presence of trained staff on the platform to signal to the train driver, make announcements, prevent passen- gers alighting, etc.

Automatic systems There were no automatic fire detection systems or sprinkler systems at King’s Cross. There was a manually controlled sprinkler system installed on the fire affected escalator, but it was not brought into use.

Fire alarms There were no audible or visual fire alarms at King’s Cross. There is clearly a major problem with the use of alarms in confined spaces, where crowd surges can lead to very serious incidents with the risk of crushing, but audible or visual warnings at the entrances to stations could be beneficial.

Communication with emergency services LUL had a procedure whereby a staff member discovering or being notified of

a fire contacted a station supervisor, who then went to the site of the reported fire. used fire extinguishers if appropriate, and then called the fire brigade. London Fire Brigade had ore- viously objected to this procedure as causing unnecessary delays.

On the evening in question, the supervisor who was notified of the fire attempted to control it but remained out of touch with other station super- visory staff. This resulted in delays in notifying the fire brigade and in initiat- ing LUcs emergency response pro- cedures. Control of train movements and involvement of LUL staff in eva- cuation and fire brigade rendezvous were delayed accordingly.

All of these points are addressed in much more detail in Desmond Fennell’s report’. To draw some general lessons, one can say that the fire re-emphasized the importance of a coherent fire pro- tection strategy based on a realistic estimate of risk (derived from the col- lection, analysis and interpretation of fire statistics and fire incident reports) and the development of appropriate management responses in terms of hardware (detection systems, sprink- lers, escape routes) and organizational factors (staff training and availability, liaison with emergency services, emergency planning, evacuation proce- dures). This applies in particular to confined areas where large numbers of the public may be present at one time.

Alun Roberts

Fennell, D. ‘Investigation into the King’s Cross Underground Fire’, HMSO, November 1988 Moodie, K. ‘Damage assessment and overview of the technical investigation’ IMechE Seminar, July 1989 Moodie, K. and Jagger, S. F. ‘Results and analysis from the scale model tests’ IM- echE Seminar, July 1989 Simcox. S., Wilkes, N. S. and Jones, I. P. ‘Computer Simulation of the flows of hot gases from the fire at King’s Cross Under- ground Station’ IMechE Seminar, July 1989 Roberts, A. F. ‘The King’s Cross fire: a correlation of eyewitness accounts and the results of the scientific investigation’ IMechE Seminar, July 1989

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