One of the most vital aspects of the safety of a building in a situation of a fire incident is the plausibility of a safe escape of the occupants within the building, also called evacuation (Kobes, et al., 2010). Getting a good understanding of how occupants behave in a fire emergency and evacuation is pivotal to bring fire safety measures in line with the needs of occupants at the time of an incident. A crucial prerequisite to the safety is that the fire safety facilities accommodate an independent and adequate fire response performance by the occupants of the building. However, viewing the several fire accidents and casualty rates seen in the past decade, it appears that the initiatives required by the fire safety regulations do not often provide the support needed by the occupants of burning buildings.
This thesis aims to focus on the aspect of evacuation in the fire safety of high rise buildings in the UK, which is done through means of taking Meridian Quay Tower, Swansea, as a case study, by running a simulation model (…). The following section lays out the foundation to form an understanding of our study. It entails the literature on fire safety in high rise buildings in the UK.5.
2 High Rise BuildingsAcross the UK there are currently over 270 existing high-rise buildings and structures (AMA Research, 2017), of which about 70% of high-rise buildings, currently under construction or under consideration, across the UK are primarily residential, but with an element of mixed-use, e.g. retail, community, or leisure. Key factors affecting the development of high-rise buildings include cost, space efficiency, wind & seismic considerations, structural safety, risk challenges both on-site and in completed buildings, the speed of elevators, new building materials to potentially replace steel and concrete and damping systems. In addition, significant technical and logistical factors include pumping and placing concrete at extreme heights, and craning and lifting items to extreme heights.The definition of high-rise buildings has been observed to vary from one study to another. For instance, the AMA Research looks at UK regional and London developments of high rise buildings for 15-20 storeys and above.
On the other hand, Designing Building Ltd., a database for the construction industry in the UK, classifies a high rise building to consist of 7-10 storeys and above. According to Hall (2011), the main functions of this type of buildings are office buildings, residential buildings (like hotels and apartment buildings) and healthcare facilities. Each of these categories presents unique fire safety characteristics from the standpoints of both infrastructure and population of the building. The analysis of the function of a building is therefore crucial to predict the possible behaviour of the occupants and provide an adequate fire safety design and evacuation strategies. High – rise buildings present a lower number of fatality rates as compared to the low – rise buildings of the same type.
However, the attention on this type of buildings can be raised by the fact that even a single high – rise building fire may cause a significant number of casualties or fatalities, due to the possible higher occupants’ population. Researchers have performed in-depth analyses of particularly memorable incidents in order to study the high – rise fire problem. Examples are available in the literature, such as the MGM Grand Hotel Fire where the total number of fatalities was 85 (Best & Demers, 1982, Clark County Fire Department, 1981), the bombing of the Oklahoma Murray Federal Building resulting in 168 fatalities (Mallonee et al., 1996) or the Chicago Cook County Administration Building Fire (Proulx & Reid, 2006) that resulted in 6 fatalities.
The Research on high – rise buildings became a growing concern to safety committees working on codes towards the end of the 1960s (Galbreath, 1969, Melinek & Booth, 1975). Among many, the design of exit stairs was the main issue that received significant attention from analysts at the time, providing important formulae of exit stair width and minimum total evacuation times. Furthermore, significant work in this area was performed in the 1970s and 1980s (Pauls, 1978; Pauls, 1988). It is noteworthy that the focus of these studies was the application of the hydraulic movement models, more importantly, taking into consideration the behavioural factors. This allowed the inclusion of the pre-evacuation activities of the occupants in the analysis of the actual evacuation times of tall buildings, giving a greater accuracy to the results. More recently, a great sense of awareness on this topic was raised by the World Trade Centre terrorist attack of 9/11 (Averill et al.
, 2005). The event results in a paradigm shift to the assessment of high – rise buildings safety. It showed the importance of providing robust means of egress and the need for further investigating the interactions between the infrastructure, the procedures and the behaviour of the occupants (Galea et al., 2008a, Galea et al., 2008b).5.3 Challenges to fire safety in high-rise buildings5.
3.1 Smoke Control5.3.2 Emergency Lighting5.3.
3 System control across a high-rise building’s fire systemGetting information to the person in control so they can interpret and act on it quickly is vital. The system in any complex building, especially a high-rise, will be networked with thousands of individual devices, linked to hundreds of panels and repeaters.5.3.4 InterfacingInterfacing must be achieved without affecting the performance of the core fire system, or the interfaced services. 5.3.
5 5.4 RegulationsA raft of legislative guides and EN/BS codes and compliances regulate the design of High rise buildings. In some circumstances, an approved ‘Engineered solution’ may be authorised.
In the 1950s and 1960s, blocks of flats became taller and taller without a great deal of change to the internal layout. It is for this reason that the internal design for Lakanal House included corridors of 24m from a single escape stair – with escape balconies for each flat, including the 15th-floor flats. At the time, architects questioned the wisdom of this venture, but at that time the codes of practice were guidelines only and did not have the same power as formal regulations.From the early 1970’s the primary UK fire safety legislation was the Fire Precautions Act 1971 and although it was applied to tall buildings that carried out certain roles or functions (Hotels, places of work etc.) it was not designed for privately occupied buildings and flats. As such there was not an ongoing regime of inspection and licencing in many high-rise accommodation buildings.
Various other pieces of other legislation and design maintenance criteria would impact on fire safety in High Rise Buildings, but they required the owners to implement them. Unfortunately, this seldom happened. The 1961 Housing Act (now Housing Act 2004). laid down various safety and emergency measures for houses in multiple-occupancy, but these usually applied within actual flats.
With the introduction of the RRO (Regulatory Reform Order-Fire Safety 2005), things changed. One of its requirements was a level of risk assessed fire safety and suitable control measures in communal areas. This tied in with the Housing Act brought about an enforceable statutory duty on building owners and landlords. (…..
) (…). Although the building codes establish the minimum requirements for the design of a high – rise building, (Reference) suggests that additional life safety features are often necessary to mitigate the issues deriving from the complexity of these types of buildings and the additional difficulties they impose on fire-fighting and rescue operations. The perspective of the technical International guidance, like the NFPA101 in the U.S. NFPA, 2012, or the Approved Document B (The Building Regulation, 2006) in the UK, is significant to provide information on the design of the egress components (e.
g., geometric characteristics of the stairs) that can be applied for high – rise buildings. (…)5.5 Elements of evacuation in fire safety126.96.36.199.25.
188.8.131.52.6 Various evacuation strategies in high rise buildings On the other hand, further information on the behavioural issues associated with the egress performance during high – rise building evacuations is still required. General concepts can be employed although additional specific recommendations are required given the particular features of this type of buildings. Dedicated recommendations have been provided by several national and international committees, e.
g. the GB50045 – 95, Code for Fire Protection Design of Tall Buildings in China (GB50045 – 95, 2005), the Fire Safety Requirements for super high – rise residential buildings in Singapore (Singapore Civil Defence Force, 2006) or the chapter 7 of the Fire and Life Safety of National Building Code of India (Bureau of Indian Standards, 2005). 5.7 ConclusionSeveral questions have been prompted by the studies about the adequacy of the current fire safety regulations and emergency procedures for high – rise buildings: For what type of evacuation scenarios should we design high – rise building? What egress components are recommended to evacuate a high – rise building? Are elevators suitable for evacuation purposes? What design measures or procedures should be employed to improve egress efficiency? In order to answer these questions in reflection to the current issues faced by the industry, a thorough exhaustive study is necessary which encompasses a wider range of variables distinctive to each category of building type and functionality. In addition, the lack of knowledge can be observed in terms of the behavioural aspects taking place during a high – rise building evacuation (Kuligowski, 2011). Hence, specific recommendations on the evacuation strategies for high rise buildings rely on a previous analysis of the single variables to be investigated. For this reason, there is a need to perform a review of the literature available on the main variables affecting high – rise evacuations, such as the egress components employed (i.
e., stairs, elevators, etc.) and the strategies in use (phased evacuation, total evacuation, defend – in – place, etc.). In particular, there is a need for an analysis of the studies concerning the evacuation through vertical transport and methods to encourage the use of elevators for evacuation.
There is also the need to investigate if the use of different components has been studied individually or if there are attempts to investigate the combinations of different egress strategies.