There is great variability in the way people respond to the threat of fire in large buildings. DAVID BARBER from Arup Fire explores the psychology of evacuation.
Today’s buildings are becoming increasingly mixed with their uses – retail, office, hotel, apartment classifications are regularly combined within a multi-storey building. Larger buildings may also have crowd uses such as cinemas or conference facilities included. These mixed use buildings require significant pre-planning for alert systems and emergency procedures to get the desired outcomes in a fire emergency, as the response of the occupants will differ within each use classification.
In a fire situation a normal tone alarm system provides occupants of a building with an alert, but it does not provide them with any information. With the prevalence of car, security and false alarms that people are exposed to, a simple alert tone will have little impact for many occupants. To gain a desired response from the alert, the alarm must provide relevant information that is understandable and must also be supplemented with training through drills and information so the building occupants not only recognise the alert as being a fire alarm, but also have an understanding of the response expected from them.
Facility managers need to have a good understanding of the number of occupants within their building, the different classifications, and how those use classifications interact. Facility managers have typically concentrated in the past on the number of occupants but have not always considered the differences that mixed uses can introduce into a building and the influence on the motivation to evacuate.
A study that I undertook recently on behalf of the Fire Protection Association Australia has shown that a significant majority of occupants in high-rise residential buildings do not evacuate on hearing the fire alarm, unless they are directly under threat from the fire, i.e. it is in their unit or they can see/smell smoke within their common corridor.
LACK OF MOTIVATION
My research has shown that occupants in residential high-rise buildings are often reluctant to evacuate when a fire alarm sounds due to a lack of information, combined with a desire to stay within their unit where it is safe, if they are not directly threatened by a fire. This lack of motivation to evacuate is due to the occupant being within their home; their behaviour and response to a fire emergency is different at home than it would be at their place of work or another public setting, such as a shopping centre.
The motivation to evacuate has been studied in detail for residential high-rise buildings to understand the most appropriate strategy for fire emergency response. My research has shown that an expectation of evacuation for all building occupants is flawed with regard to high-rise residential buildings. A more pragmatic and efficient process is the so-called ‘protect in place’ approach, whereby occupants remain in their units on detection of fire and only those directly threatened by fire or requested to leave by attending fire-fighters need to evacuate. The protect in place strategy is combined with an alert system and simple emergency response procedures that are specific to high-rise residential buildings.
These fire protection measures, along with simple and clear instructions posted within common corridors, may provide an effective method for achieving better fire emergency response for occupants of high-rise residential buildings. The recommended measures also provide a system that meets with the underlying human behavioural aspects of occupants. The fire protection measures that I favour have been developed to provide an effective response strategy for the particular behavioural and motivational aspects specific to high-rise residential occupants.
POSSIBLE BUILDING CODE CHANGES?
The research undertaken has shown that the current approach adopted by the BCA (Building Code of Australia) of using one method of alert and expected evacuation response for all high-rise building use classifications needs further consideration and potential change, as the motivation to exit and occupant response differs within each use classification.
While the research was carried out for high-rise residential buildings, the findings are also very relevant for mixed-use buildings, as one of the key discussion aspects of the research is an occupant’s motivation to evacuate. The motivation to evacuate – or the factors that de-motivate – are highly relevant for implementing an efficient and successful evacuation strategy.
MIXED USE BUILDINGS
For buildings that are mixed use, the alert and emergency response procedures also need to reflect the occupant behaviour and the potential motivational behaviours that influence evacuation. Fire alarm, alert and emergency response procedures need to be designed and developed specifically for each building, as all buildings are unique, but also because of a need to take account of the use classifications within a building. While this may not be something new, the key lessons to be drawn from my research are an understanding of the motivating factors for occupants to evacuate and how to best implement alerting systems and evacuation procedures to achieve the desired occupant response.
Office buildings typically have some of the most efficient and effective fire emergency response outcomes, in part due to the legal health and safety framework that requires employers to provide a safe work environment, but also due to the underlying motivation for employees to respond in the desired manner when a fire alarm sounds – to stop work and evacuate.
An office or other workplace can effectively implement evacuation procedures such as those within AS3745 – Emergency Control Organisation and Procedures for Buildings, Structures and Workplaces (2002), due to employees being required to undergo emergency response education as part of their regular health and safety training. Regular drills are also important, whereby wardens and building occupants can rehearse their response to ensure a successful outcome in a real fire emergency.
Shopping centres have specific issues that need to be addressed to achieve a successful outcome in a fire emergency, with many occupants having little desire to evacuate when an alert sounds. While shopping centres are very different to high-rise residential buildings, the issues to be addressed in achieving a successful response to a fire emergency are similar: there are occupants with a lack of motivation to exit, and there is a need for an alert that has information that is relevant.
Shopping centres are destinations where occupants are engaged in an activity and have little tolerance for interruptions or delays, whether that activity is purchasing groceries or spending a few leisurely hours window-shopping. When a fire alarm sounds, the occupants have little motivation to change their current actions and therefore a successful evacuation needs to be based on an understanding that occupants typically have little information on the fire emergency (unless directly threatened) and will therefore have no motivation to change their actions, even with the alert or evacuation tones sounding.
Hence, for a retail environment, the use of a public address system to alert occupants and guide their behaviour is essential. This must be combined with effective response procedures that are understood by all staff, as it will be the staff in each retail store who will need to react quickly and correctly and inform customers when an alert sounds. Providing alert and evacuation tones without use of a PA system will typically result in confused building occupants and will not normally lead to an effective evacuation. Occupants within a shopping centre will also expect the staff of each store to understand what emergency event is occurring and expect staff to provide accurate response instructions. In large shopping centres, complete evacuation of the centre would be rare and normally only the zones impacted by a fire would require immediate evacuation. Centre managers must understand the lack of motivation to exit by the occupants and how to best utilise the PA system and store staff to achieve the most effective outcomes.
For a building of mixed uses, combining retail with apartments and offices, the building manager needs to be aware that an alert system set up for one use classification will not be suitable for all uses, due to the differing motivation to evacuate. Hence there will need to be different approaches to alert and response procedures and the use of PA systems for the different use classifications to ensure a predictable and safe response to a fire emergency.
Building managers need to tailor specific procedures to their properties based on all these considerations.
David Barber is a principal and leader of Fire Australasia, Arup Fire. He and his team consult widely on specialist matters of fire management, prevention and protection within the built environment.
The above article elaborates on themes raised by Barber at Fire Australia 09, the latest annual conference of the Fire Protection Association of Australia.