A critical review of “travelling fire” scenarios for performance-based structural engineering

Abstract

Many studies of the thermal and structural behaviour for large compartments in fire carried out over the past two decades show that fires in such compartments have a great deal of non-uniformity (e.g. Stern-Gottfried et al. [1]), unlike the homogeneous compartment temperature assumption in the current fire safety engineering practice. Furthermore, some large compartment fires may burn locally and tend to move across entire floor plates over a period of time. This kind of fire scenario is beginning to be idealized as travelling fires in the context of performance-based structural and fire safety engineering. This paper presents a literature review of the travelling fire research topic and its state of the art, including both the experimental and theoretical work for the past twenty years. It is found that the main obstacle of developing the travelling fire knowledge is the lack of understanding of the physical mechanisms behind this kind of fire scenario, which requires more reasonable large scale travelling fire experiments to be set up and carried out. The demonstration of the development of a new travelling fire framework is also presented in this paper, to show how current available experimental data hinder the analytical model development, and the urgent need that the new travelling fire experiments should be conducted.

An extended travelling fire method framework for performance‐based structural design

“…Apart from the WTC buildings, high levels of temperature inhomogeneity in the large compartments with such developing/spreading fire features have been reported on many other occasions: the First Interstate Bank Building in Los Angeles in 1988, the Windsor Tower in Madrid in 2005, and more recently the Plasco Building in Tehran in 2017 . Furthermore, experimental evidence from dedicated tests has also shown a high degree of temperature heterogeneity in such compartments and the corresponding threat to the structures, with relevant experiments reviewed by Stern‐Gottfried and Rein in 2012, and Dai et al in 2017 . These facts underline the urgent need for a better description of fire scenarios for structural design, recognizing the trend towards the larger spatial layouts often preferred in contemporary architecture.…”

“…In recent years, the problem described above has been addressed with the so‐called travelling fire methodologies, which relate to fires that are assumed to burn “locally” but which are presumed to move across entire floor plates over a period of time. There are three explicit representations of travelling fires that can be found in the literature: Clifton's model (1996), Rein's model and its subsequent refined versions (2007 onwards), and an extended travelling fire methodology (ETFM) framework conceptually put forward by the authors in 2016 . The latter ETFM framework is postulated on a “mobilized” version of Hasemi's localized fire model for the fire plume near the structure (ie, near field), combined with a simple smoke layer calculation that utilizes the FIRM zone model for the areas of the compartment away from the fire (ie, far field).…”

“…Schematic of the ETFM framework (A) in sectional plan view and (B) in sectional elevation view, adapted from Dai et al [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…Once the fire is “travelling,” the near field has a leading edge representing the fire spread, and a trailing edge representing the burnout of the fuel. Though well understood in concept, the main research efforts on travelling fire methodologies inevitably rely highly on an oversimplified assumption—that travelling fires are mostly fuel‐load‐driven, that is, where ventilation plays a very limited role in dictating design fires in large compartments.…”

“…The full‐scale travelling fire experiments considered include the British Steel Technical/Fire Research Station 1993 fire test series, the Building Research Establishment tests in the Cardington Large Building Test Facility in 1995 to 1996 (Test 6, Simulated Office), the Moinuddin and Thomas fire test series in 2005, the Veselí Travelling Fire Test in 2011, the Edinburgh Tall Building Fire Tests (tests number 11 and 12, using wood sticks) in 2013, the Malveira Fire Test in 2014, the Tisova Fire Test in 2015, and the TRAFIR‐RISE Fire Test in 2018. The detailed test set‐up of these travelling fire experiments has been reviewed by the authors in a previous work, except for the TRAFIR‐RISE Fire Test which is so far unpublished. There is no data point for another very relevant travelling fire test, the St. Lawrence Burns Project, as there is limited access to the detailed test data.…”