Supermarket - Efficiency and Emergency Evacuation
(updated 31st August 2007)
Keywords: simulating people, simulating crowds, simulating crowd dynamics
Supermarket spatial utilisation analysis. Shows areas of highest utilisation (average use over day).
Paraguay supermarket fire kills 283
Mon 2 Aug, 2004 3:14:21 GMT By Daniela Desantis
ASUNCION, Paraguay (Reuters) - A fire has swept through a supermarket packed with shoppers on the Paraguayan capital's outskirts and killed at least 283 people, police say. More than 100 people were injured in an inferno that officials said was caused by a gas explosion near the food court of the huge Ycua Bolanos supermarket, causing part of the roof to collapse. Flames then engulfed a parking lot underneath. Police said the toll was expected to rise on Monday. "There are no words for this," said Orlando Correa, weeping minutes after identifying the corpse of his six-month-old nephew. He searched for his sister among lines of charred bodies in a nearby discotheque that became a makeshift morgue. Police said they were probing reports shoppers were trapped inside after the supermarket locked its doors to stop people looting or leaving without paying. Firefighters found its main door closed when they arrived, police said, but supermarket officials denied doors had been locked. Paraguay, a country of 6 million people, was calling it the nation's worst tragedy since a 1930s war with neighbouring Bolivia that killed thousands. In chaotic scenes, rescuers carried bodies, some black from burns and smoke, out of the supermarket in their arms. Firefighters took charred body remains out of the supermarket on stretchers. Television said there were about 700 people in the complex at the time but there was no official estimate. "There are still bodies inside the building, but firefighters cannot enter because of the ruins and the danger of collapse," Paraguayan police chief Humberto Nunez told Reuters. Some of the burned bodies were found inside the supermarket hugging each other, including a woman with a small child in her arms, a firefighter told local radio.
BURNED ALIVE IN CARS
Other victims were burned alive in their cars as the blaze swept though a parking lot underneath the supermarket, local television reported. Dozens of ambulances and fire engines gathered outside the large supermarket, located in a working-class district, where residents of all economic classes do their Sunday shopping. Plumes of black smoke rose from its roof six hours after the blaze. The supermarket's owner was taken into custody and is being investigated, the prosecutor's office said. Some survivors were thrown on the backs of open trucks that were driven to hospitals. One woman wept outside the supermarket, waiting for news of her missing 14-year-old son. "I need information on my son. He's not in any of the hospitals I've contacted," she said. "It is a moment of huge grief and tension, and we are here to give a voice of support to people who are suffering so much," said President Nicanor Duarte Frutos, who rushed with his wife to the scene of the blaze. The disaster appeared to have stretched the emergency services of one of South America's poorest nations. Local television showed firefighters trying to plug holes in leaking water hoses with the soles of their boots. Local media called on citizens to donate basic supplies, like gloves, to hospitals. Private hospitals opened their doors to victims of the blaze but were short of respirators. neighbouring Argentina said it was sending Sunday night a Hercules transport plane with medical supplies to Paraguay.
See also - Fire in Madinah
Operational Efficiency AND Safety
As it can be seen from the tragedy above, the efficiency AND operational safety of places of public assembly are key issues in the world today. Ever more we at Crowd Dynamics see places of public assembly becoming higher risk environments from the threat of international terrorism and lack of concern over the basic requirements for emergency egress (see Crowd Disasters for a horrific list). It is essential that operational efficiency and adherence to acceptable codes of practice are the responsibility of the owner/operators and these responsibilities cannot be ignored.
Optimising space is a major feature of the Myriad suite and the models below indicate how comparative analysis of entry systems impact the shopping dynamics and congestion points in the store. The diagram to the left is our suggestion for an improved flow system (different entry/exit routes) and has an increased floor space for merchandise. Furthermore the layout will focus shoppers to the central area. The addition of an extra aisle increases circulation AND reduces congestion/conflict. By this simple change we can facilitate a higher throughput rate and increase merchandise area. We would refer to this process as "crowd simulation".
Interaction map of a supermarket
Further improvements can be made by analysis of the stock turn and checkout utilisation. Studies at local supermarkets suggest a 30% improvement in space utilisation, higher throughput and less congestion/conflicts.
Existing layout Alternate layout
Spatial Utilisation
The diagram above (alternate design on the left - exiting on the right) indicates the disproportionate utilisation of the checkout areas. This is exasperated by the location of the "express" checkout in the most utilised area. These express checkout can reduce efficiency of the whole system by up to 10% of the desired throughput and is a non-intuitive result from queuing theory within the Myriad system. This is easily proved but is a persistent feature of all major supermarkets. Not only are they inefficient for the majority of shoppers but their location displaces the throughput to further checkouts. These two effects are subtle but have a dramatic and unperceived result in increasing shopper conflict and congestion. Red areas are high conflict/highest congestion areas.
Existing layout Alternate layout
A 3D transform makes the map clearer - the flatter the landscape the more even the shopper distribution around the store (see below). By adding marketing information (Sales of items by area/basket) we can provide a comprehensive analysis and design service.
Existing layout Alternate layout
Navigating the space (density/congestion/conflict) is represented as a topography (like a landscape) the more ridges, the more difficult the movement through the space. Flatter landscapes interaction/congestion are one of the desired design criteria for complex spaces.
Throughput/conflict analysis
One of the key elements to stress free shopping is the ease of progress through the store and ease of access of checkout. There is a financial balance between the number of checkout tills, their location, utilisation and potential for queuing/congestion to impede other shoppers. It is a delicate balancing act that has, at one extreme, idle checkout tellers or severe congestion. Too few checkouts and congestion rapidly creates a shopping trolley gridlock. Too many checkouts reduces merchandising space and increases costs. The location and throughput can be tested in the Myriad system until optimal solutions are found. These vary for time of day and day of the week. However the rapid analysis that Myriad offers means the user can test a wide range of potential solutions very quickly.
Numerical data such as throughput, depth of queue, time in the system, space required for different checkout strategies and conflict/congestion analysis are all part of the Myriad suite output analysis.
Plotting the interactions
Every interaction in a congested environment is a delay and adds to frustrations and general disorder within the shopping dynamics. The Myriad analysis of the above two designs highlights the differences. The two graphs below indicate the number of high congestion interactions encountered by a shopper as they progress along the same route, covering the same distances, shopping for the same items. The first graph is the right hand side design (existing) and the second graph is our modified design. To produce these you use the mouse to "walk" through the store and the graph highlights the levels of service and interactions you may encounter.
The axes of these graphs are interactions/collisions versus travel distance. The higher the number of interactions (redder peaks), the slower the progress and more uncomfortable the shopping experience.
Graph 1 - Existing layout
Graph 2 - Alternate layout
We can see the differences immediately, less interaction, less congestion, easier transition across the shopping area. You read these maps like you would read an OS map if you were out hill climbing, the more peaks - the tougher the journey. Flatter landscapes are approaching optimal, even density, minimum congestion, minimum effort, greater throughput.
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