Questions are being raised as to how many people were in the nightclub at the time of the incident.  This will become an important issue as the inquiry into the disaster progresses as the level of club occupancy could be used as a factor in contributing to the severity of the disaster and hence in apportioning responsibility.  Another issue that has been raised is whether or not more exits would have made a material difference to the outcome. To examine these issues we can do some simple analysis based on a number of assumptions and what the media are currently reporting.

So what do we (think we) know about the Kiss fire incident according to accounts in the media:

1) The club has a floor area of 615 m².  However, it is not known how this breaks down to dance floor, bar, toilets, circulation space etc.

2) The maximum travel distance to the front door is reported as being 32m.

http://world.time.com/2013/01/29/focus-turns-to-brazilian-club-safety-after-fire/

3) The maximum legal occupancy of the club is reported as being 691 people.

4) The only available exit has a width of 3m.

http://g1.globo.com/rs/rio-grande-do-sul/tragedia-incendio-boate-santa-maria-entenda/platb

5) The club owner insists that there were only 600 to 700 people in the club at the time of the incident.  However, the band’s guitarist told media that there were between 1200 and 1300 people in the club at the time and the police have given the same estimate.  The owner suggests that the higher estimates are due to clubers cycling into and out of the club.

http://www.foxnews.com/world/2013/01/31/nightclub-fire-that-killed-235-prompts-inspections-closures-night-spots-across/

6) It has now been reported that the band did in fact use flares during their show.  The flares were outdoor flares which are cheaper ($1.25 a piece) then indoor flares ($35 each).

http://world.time.com/2013/01/29/focus-turns-to-brazilian-club-safety-after-fire/

7) According to what I understand to be the fire certificate, the club is credited with having 2 emergency exits — hence 3 exits in total, one main and 2 emergency.  However, this is not clear from the article which later refers to these ‘emergency exits’ simply as ‘exits’, in which case the club may have been certified as having 2 exits, 1 main and 1 emergency exit. So it appears from the media accounts that the club was certified as having 3 or 2 exits — depending on the interpretation of the article.

http://g1.globo.com/rs/rio-grande-do-sul/noticia/2013/01/boate-informou-em-laudo-ter-duas-saidas-diz-brigada-militar.html

QUESTIONS:

In discussion with a Brazilian fire safety consultant based inSao Paulo, Dr Rodrigo Machado Tavares, Dr Tavares suggests that the local fire codes would require the Kiss nightclub to have:

– three exits,

– emergency lighting,

– emergency exit signage,

– an alarm system.

This answers many of the questions posed in my last blog (Yet Another Nightclub Tragedy — Grief tainted with anger, 29/01/13) however, it poses many serious questions concerning the licensing, inspection and enforcement process in Brazil.

Furthermore, it appears that the expired license has been reported as suggesting that the club had three (or at least two) exits.  Unless the missing exit or exits have been bricked up since the license was issued, or that the exit(s) were there but were locked or blocked during the incident and so could not be used, how could a license be issued stating that the club had three (or two) exits?  One has to ask if inspections of the club were ever performed.  If they were performed, how could an inspector fail to notice that two (or one) exits were missing?

Given that the nightclub had only a third of the legally required number of exits, one has to wonder whether this would have made a material difference to the outcome.

Concerning the number of people in the club, this is important as it is the manager’s responsibility to control the number of people in the club.  The manager suggests that the there were 700 people in the club, as allowed by the questionable ‘license’.  If there were 700 people in the club, this would be of benefit to the manager as it suggests overcrowding — his responsibility — would not have been a major factor and refocuses attention on the questionable fire license.  If there were 1200 people in the club, this deflects some degree of blame from the band — for allegedly starting the fire using flares — and for the code enforcement agency for permitting the license in the first place.

Is it likely that there were 1200 people in the Kiss Nightclub at the time of the incident?

SIMPLIFIED ANALYSIS:

Let’s do a simplified analysis on numbers of exits and number of people.  Note that this analysis is crude and a more thorough analysis would be required to establish the relevance of these key parameters.  The simplified analysis is dependent on a number of simplifying assumptions detailed below.

1) Assuming the 3m available exit width and a population of 1200 and 700, approximately how long would it have taken for the population to get out?

Let’s simplify the calculation and assume the population reacts immediately (zero response time) and let’s also assume that all the people are queued up at the exit ready to go.  Assuming a unit flow of 1.33 p/m/s (UK ADB) then the exit could sustain a flow of 3.99 p/s and it would require:

– at least 300 s for 1200 people to exit and

– at least 175 s for 700 people to exit.

2) How much time would be available for people to get out?  This is extremely difficult to estimate without doing a detailed analysis.  But let’s use the Rhode Island Nightclub fire as a rough guide.  After about 100 s conditions in the Station Nightclub were non-survivable. The floor area of the Station Nightclub was about 412 m² and so the Kiss nightclub is some 50% larger.  Based on this let’s assume that people had 50% longer to get out, making it 150 s for non-survivable conditions to develop.  This is admittedly a very crude estimation and may over estimate the amount of time available.

In 150 s, using the single available exit we could expect about 600 people to get out:

– generating a death toll of 100 people assuming there were 700 people in the club, as claimed by the manager,

– generating a death toll of 600 people assuming the band/authorities are correct and there were 1200 in the club.

Given the current death toll of 235, it is possible that there were 835 people in the club.  If correct, this would suggest that while the club was overcrowded, it is unlikely that there were as many people as suggested by the band/authorities.

A note of caution, remember, the assumptions that have been made are rather crude. The population is unlikely to have had zero response times, but evidence from the Rhode Island fire would suggest that in these types of situations, occupant response times are quite small of the order of a few seconds.  We can slightly improve these approximations by relaxing the zero response time assumption and assuming that the first people start to move in 10 s and that the closest people to the exit are located a third of the maximum distance (11m) and that the people located here move at 1.1 m/s.  This would add about 20 s to the estimated exit times OR reduce the available safe egress time by 20 s.  So let’s assume that we have 130 s to get out.

In 130 s, using the single available exit we could expect about 519 people to get out:

– generating a death toll of 181 people assuming there were 700 people in the club, as claimed by the manager,

– generating a death toll of 681 to be killed if the band/authorities are correct and there were 1200 in the club.

Given the current death toll of 235, it is possible that there were 754 people in the club.  This would shift the club occupancy even closer to that suggested by the nightclub owner.

We may also assume that the unit flow achieved by the exit was better than that prescribed in the UK regulations, which by their nature are conservative.  This would get more people out of the nightclub within the 130 s available time, increasing the size of the estimated population within the club.  However, in such situations, especially after the first few people have exited, the exit flow will become competitive rather than ordered, which will tend to reduce the exiting efficiency and hence the achieved unit flow rate.  In reality, the unit flow rate achieved by the exit will vary throughout the evacuation, being somewhat greater than that specified by the regulation at the start of the evacuation and being somewhat less towards the end of the evacuation.  Without undertaking a detailed analysis it is difficult to suggest a reasonable value for the unit flow rate, so for the purposes of this blog we will keep it as it is.

It is worth noting the following:

– if the average unit flow rate of the exit is greater than that used in these calculations, more people would have been able to exit in the available time and hence the estimate of the club occupancy would go up,

– if the average unit flow rate of the exit is less than that used in these calculations, fewer people would have been able to exit in the available time and hence the estimate of the club occupancy would go down.

Given the uncertainties I will stick to the initial estimates.

3) What would have happened if there were the legally required 3 exits in the club?  To answer this requires us to know the total available exit width.  Let’s assume that the club would have followed UK requirements.  An assembly space of more than 600 people would require 3 exits (as apparently does the local requirements).  Using BS 9999, the minimum total exit width for the 3 exits would be 4.3m.  Here we assume that all three exits have the same width.

If we make similar assumptions to that in (1) and in addition that all three exits were available and the population is equally divided between the three exits, then the combined flow would be 5.7 p/s and :

– 700 people would be able to exit in 123 s

– 835 people would be able to exit in 147 s

– 1200 people would be able to exit in 211 s

Assuming the same amount of time is available for safe egress i.e. 150 s, then:

– all 700 people would be able to safely evacuate, i.e. the legal occupancy would have been able to safely evacuate.

– all 835 people who are estimated to have been in the club would have managed to safely evacuate

– of the 1200 people, 855 would manage to get out, and the death toll would have been 345.

So these simplistic calculations suggest that if the club and the legally required minimum number of exits (3) with an exit width as specified by the BS 9999 and:

– the legal maximum population (700), then it is possible that everyone would have managed to evacuate before conditions in the club became non-survivable.

– if the population of the club was 835, then it is possible that everyone would have managed to evacuate before conditions in the club became non-survivable.  So even though the club was overcrowded on the night, it is possible that everyone would have managed to evacuate.

– if the population of the club was 1200, the population suggested by the band/authorities, then it is possible that 855 people would have managed to evacuate before conditions in the club became non-survivable and 345 people would have died.  So if the population was as high as 1200, even if the legally required exit capacity was provided it is unlikely that everyone would have managed to evacuate.

It has to be emphasised that these calculations are extremely crude, but they serve to demonstrate how important it is establish the correct number of people that were in the club at the time of the incident.  They also demonstrate that had the club had the required number of exits, it is possible that the death toll in this incident could have been significantly reduced.

To do a more thorough analysis on this incident would require fundamental data describing the club and the materials within the club, the number of people in the club and their distribution.  With this information it would be possible to undertake sophisticated fire and evacuation analysis of the type undertaken for the Rhode Island Nightclub fire.

Rhode Island Fire Simulation:

https://www.youtube.com/watch?v=o197yeup1BQ&list=PLC82636C7790DE890&index=1

Rhode Island Coupled Fire and Evacuation Simulation:

https://www.youtube.com/watch?v=gmPOIriMiyU&list=PL482FD999D5793B82&index=1

Paper describing simulations: http://fseg.gre.ac.uk/fire/pub.asp

Paper 223. “Coupled Fire/Evacuation Analysis of the Station Nightclub Fire”. Galea E.R., Wang, Z., Veeraswamy, A., Jia, F.,Lawrence, P., and Ewer, J. Proceedings of 9th IAFSS Symposium Karlsruhe,Germany, 2008, ISNN 1817-4299, pp 465-476. DOI:10.3801/IAFSS.FSS.9-465

http://www.youtube.com/FSEGresearch/