Transient volcanic ash plumes: Morpho-dynamical evolution and source properties

Transient volcanic plumes, typically generated by Strombolian and Vulcanian eruptions, are time-dependent features characterized by rise and development time scales similar to the eruption duration. Their morphological and dynamical properties are thus strongly related to the source conditions and evolution over time, i.e. (ejection duration, spatial spreading, ejection angle, time interval between pulses). In this study, the shape evolution and dynamics of initial transient volcanic plumes development, as well as their relation with discharge history, have been investigated using high-speed and high-resolution visible-light and thermal infrared videos. Physical parameterization of the plumes has been performed by defining their front velocity, volume and apparent surface temperature. Optical flow computer vision tool and fractal dimension analysis were applied for the first time in order to extract plume velocity field and shape complexity evolution over time, respectively. The source conditions were characterized both qualitatively, in terms of number, location, duration, and frequency of individual ejection pulses, and quantitatively, in terms of time-resolved ash eruption rate and a newly-defined instability factor. The newly proposed, image-based method I developed to retrieve discharge rate provides results that are comparable with previous methods but with more than one order of magnitude increase in time resolution. Results show that the connection between source properties and the dynamical and morphological features of transient plumes holds true for every one of our study cases, which encompass a variety of eruption styles and plume heights and shapes. In particular, plume front velocity, temperature decay, and plume complexity, as measured by fractal dimension, all follow complex evolutions which are intimately linked with the discharge history at the vent. Of the different factors that characterize vent discharge, lateral shifts in the ejection (from, e.g., vent shifts or changes in vent geometry or angle of the ejection) and temporal fluctuations, including the tempo and intensity of ejection pulses and other changes in the discharge rate, exert the strongest controls on plume evolution. These lateral and temporal changes at the vent can be combined in a general source instability factor that, by controlling the formation of the vortexes at the base of the plume, eventually determines the modes of air entrainment and the overall evolution of the plume. The connection between source instability and plume dynamics that I quantified in this study brings new understandings on the formation and initial development of unsteady volcanic plumes. Settings of new characterization tools such as fractal analysis and time-dependent discharge rate show promising results and potential for new monitoring resources

Physics of puffing and microexplosion of emulsion fuel droplets

The physics of water-in-oil emulsion droplet microexplosion/puffing has been investigated using high-fidelity interface-capturing simulation. Varying the dispersed-phase (water) sub-droplet size/location and the initiation location of explosive boiling (bubble formation), the droplet breakup processes have been well revealed. The bubble growth leads to local and partial breakup of the parent oil droplet, i.e., puffing. The water sub-droplet size and location determine the after-puffing dynamics. The boiling surface of the water sub-droplet is unstable and evolves further. Finally, the sub-droplet is wrapped by boiled water vapor and detaches itself from the parent oil droplet. When the water sub-droplet is small, the detachment is quick, and the oil droplet breakup is limited. When it is large and initially located toward the parent droplet center, the droplet breakup is more extensive. For microexplosion triggered by the simultaneous growth of multiple separate bubbles, each explosion is local and independent initially, but their mutual interactions occur at a later stage. The degree of breakup can be larger due to interactions among multiple explosions. These findings suggest that controlling microexplosion/puffing is possible in a fuel spray, if the emulsion-fuel blend and the ambient flow conditions such as heating are properly designed. The current study also gives us an insight into modeling the puffing and microexplosion of emulsion droplets and sprays.This article has been made available through the Brunel Open Access Publishing Fund

Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards

Many explosive volcanic eruptions produce underexpanded starting gas-particle jets. The dynamics of the accompanying pyroclast ejection can be affected by several parameters, including magma texture, gas overpressure, erupted volume and geometry. With respect to the latter, volcanic craters and vents are often highly asymmetrical. Here, we experimentally evaluate the effect of vent asymmetry on gas expansion behaviour and gas jet dynamics directly above the vent. The vent geometries chosen for this study are based on field observations. The novel element of the vent geometry investigated herein is an inclined exit plane (5, 15, 30° slant angle) in combination with cylindrical and diverging inner geometries. In a vertical setup, these modifications yield both laterally variable spreading angles as well as a diversion of the jets, where inner geometry (cylindrical/diverging) controls the direction of the inclination. Both the spreading angle and the inclination of the jet are highly sensitive to reservoir (conduit) pressure and slant angle. Increasing starting reservoir pressure and slant angle yield (1) a maximum spreading angle (up to 62°) and (2) a maximum jet inclination for cylindrical vents (up to 13°). Our experiments thus constrain geometric contributions to the mechanisms controlling eruption jet dynamics with implications for the generation of asymmetrical distributions of proximal hazards around volcanic vents

The influence of complex volcanic vent morphology on eruption dynamics

Vulkanausbrüche gelten als eine der spektakulärsten Naturgewalten unserer Erde. Gleichzeitig stellen sie jedoch auch eine Gefahr für die menschliche Gesundheit und Infrastruktur dar. Aufgrund ihrer Dynamik und ihres unberechenbaren Charakters geht von explosiven Vulkanausbrüchen eine besonders große Gefährdung des Menschen und seiner Umwelt aus. Im Zuge eines explosiven Ausbruchs werden heiße Gase und Pyroklasten in die Atmosphäre ausgeworfen. Obwohl das Monitoring aktiver Vulkane in den letzten Jahren immer weiter verbessert wurde, ist es immer noch schwierig eine konkrete Vorhersage zu den Ausbrüchen zu erstellen. Aufgrund ihrer Komplexität ist das Verhalten von Vulkanen nicht kalkulierbar. Bis heute ist weder eine Beobachtung, noch eine Messung der unterirdischen Rahmenbedingungen möglich, welche den Ausbruch steuern. Trotz dieser Unwägbarkeiten unterliegen Vulkanausbrüche dennoch physikalischen Gesetzmäßigkeiten, sodass die Möglichkeit besteht, die Prozesse im Untergrund eines Vulkans zu modellieren oder durch Experimente zu beschreiben. Aufgrund der Komplexität der Wechselwirkungen innerhalb des Systems Vulkan ist es erforderlich Experimente zunehmend realistischer zu gestalten. Sobald das ausgeworfene Material aus dem Krater austritt können wir den Ausbruch visuell Beobachten. In diesem Bereich ist das Verhalten des Ausbruchs vollständig von den Prozessen im Untergrund und von der Geometrie des Kraters abhängig. Im Vergleich zu den symmetrischen Kraterformen, welche in Experimenten und Modellen oft angenommen werden, sind die Krater in der Natur deutlich unregelmäßiger geformt. Ihre Geometrien sind oft eingekerbt und haben eine schräge Oberfläche. Zudem können sich die Kratergeometrien innerhalb kürzester Zeit verändern. Um den Einfluss der Prozesse im Untergrund zu verstehen müssen wir zuerst den Einfluss der beobachtbaren Parameter (z. B. Kratergeometrie) ergründen. Schlussendlich wird ein tiefergehendes Verständnis der Parameter, die Vulkanausbrüche steuern, zu einem Fortschritt und der Verbesserung der Gefährdungsanalysen führen. Um dies zu erreichen, habe ich Beobachtungen aus Feldkampagnen und Laborexperimenten kombiniert. Zunächst habe ich die Geometrien von Vulkankratern erfasst und deren zeitliche Entwicklung dokumentiert. Dazu haben ich die Geometrie der Krater in der Kraterterrasse des Strombolis in einer hohen Auflösung vermessen und die jeweils zugehörigen Explosionen beobachtet. Dabei konnte ich feststellen, dass sowohl die Intensität, als auch die Art und die Richtung der Ausbrüche durch Formveränderungen der Oberflächentopografie beeinflusst werden. Mittels Drohneneinsatz habe ich innerhalb eines Zeitraums von neun Monaten (Mai 2019–Januar 2020) fünf topografische Datensätze erstellt. In diesem Zeitraum war es möglich „normale“ Strombolianische Aktivität, starke Ausbrüche und sogar zwei Paroxysmen zu beobachten (3. Juli und 28. August 2019), sodass es möglich war, die verschiedenen Ausbruchstypen mit den vorherrschenden Ablagerungs- und Abtragungsprozessen zu verknüpfen. Zudem konnte ich die Anzahl der aktiven Krater, deren Positionen sowie deren Umgestaltung nachverfolgen. Da Veränderungen der Kratergeometrie und der Kraterposition auf eine Modifikation des Ausbruchsgeschehens hinweisen können, sind auch dies wichtige Faktoren für eine Gefährdungsanalyse. Die aus den Feldforschungen gewonnenen Daten zeigen deutlich die Komplexität, Vielseitigkeit und Variabilität der Formen vulkanischer Krater in einer nie da gewesenen zeitlichen und räumlichen Auflösung. Darüber hinaus haben die Beobachtungen der Vulkanausbrüche deutlich gemacht, wie stark die Beziehung zwischen dem Krater, der Kratergeometrie und dem Auswurf von pyroklastischem Material ist. Diese Erkenntnis hat eine große Bedeutung für die Gefährdungsanalyse, vor allem für Gebiete, die potentiell durch vulkanische Bomben und pyroklastischem Fallout bedroht sind. Im Anschluss habe ich eine Reihe von Dekompressionsexperimenten mit Kratergeometrien durchgeführt, welche auf den Beobachtungen am Stromboli aufbauen. Durch diese Experimente wurde der Zusammenhang zwischen Kratergeometrie und Ausbruchsdynamik bestätigt. Die verwendeten Geometrien haben eine geneigte Oberfläche mit einem Winkel von 5°, 15° und 30° und jeweils einer zylindrischen und einer trichterförmigen inneren Geometrie. Daraus ergeben sich sechs experimentelle Krater die mit folgenden experimentellen Bedingungen getestet wurden: Vier unterschiedliche Startdrücke (5, 8, 15 und 25 MPa) und zwei Gasvolumina (127.4cm3, 31.9cm3). Alle Experimente wurden bei Raumtemperatur und mit Argon durchgeführt. Trotz des vertikalen Aufbaus konnte man auf beiden Seiten des Kraters unterschiedlich große Winkel des austretenden Gases beobachten. Weiterhin war der Gasstrahl geneigt. Die Richtung der Neigung wurde durch die innere Geometrie be- stimmt. Bei einer zylindrischen Geometrie neigte sich der Gasstrahl in die Einfallsrichtung der geneigten Oberfläche. Im Falle einer trichterförmigen inneren Geometrie neigt sich der Gasstrahl entgegen der Einfallsrichtung. Der Winkel des Gasaustritts war bei einer zylindrischen inneren Geometrie immer größer als bei der trichterförmigen Geometrie. Sowohl die Winkel des Gasaustritts als auch die Neigung des Gasstrahls zeigten eine starke Reaktion auf eine Veränderung der Druckbedingung und Oberflächenneigung. Dabei zeigten sowohl der Austrittswinkel als auch die Neigung eine positive Korrelation mit dem Druck und der Oberflächenneigung. Hohe Druckbedingungen haben außerdem dafür gesorgt, dass für einen längeren Zeitraum Überdruckverhältnisse am Kraterausgang herrschten. Ein höheres Gasvolumen hat größere Gasaustrittswinkel ermöglicht. Zuletzt habe ich die Dekompressionsexperimente durch den Einsatz von Partikeln ergänzt, um so den Auswurf von Gas und Partikeln während eines explosiven Vulkanausbruchs nachzustellen. Dabei habe ich die beiden experimentellen Kratergeometrien aus den vorangegangenen Experimenten ausgewählt, welche den stärksten Einfluss auf die Gasdynamik aufgezeigt haben. Zusätzlich habe ich eine dritte Kratergeometrie verwendet, die dem aktiven Krater S1 auf Stromboli nachempfunden ist. Die Geometrie entspricht der Kratergeometrie aus der Vermessung im Mai 2019. Die S1 Geometrie zeichnet sich durch einen asymmetrischen Öffnungswinkel aus (~10° auf einer Seite, ~40° auf der anderen Seite). Zusätzlich zu den drei Kratergeometrien wurden unterschiedliche Partikel verwendet (Schlacke und Bims), mit jeweils drei unterschiedlichen Korngrößen (0.125–0.25, 0.5–1 und 1–2mm) und zwei Druckstufen (8 und 15MPa). Die Partikeldynamik, in der Nähe des experimentellen Kraters, wurde anhand der Winkel des Partikelauswurfs und der Geschwindigkeit der Partikel definiert und beschrieben. Dabei wurde festgestellt, dass die Geometrie des Kraters die Richtung und Neigung des Partikelauswurfswinkels und die Geschwindigkeit der Partikel bestimmt. Bei allen Kratergeometrien kam es zu einem asymmetrischen Partikelauswurf und im Falle von Bimspartikeln zudem zu einer ungleichmäßigen Geschwindigkeitsverteilung. Die Kombination aus Daten aus Feldkampagnen, Experimenten mit Gas und Experimenten mit zusätzlichen Partikeln zeigte deutlich den starken Einfluss der Kratergeometrie auf Eruptionen. In der Natur, führt eine modifizierte Kratergeometrie zu einem verändertem Auswurfsmuster der Pyroklasten. Im Labor haben komplexe Kratergeometrien zu geneigten Gasstrahlen, asymmetrischen Auswurfswinkeln von Gas- und Gaspartikeln und einer asymmetrischen Verteilung der Geschwindigkeit von Partikeln geführt. Auf Basis dieser Beobachtungen komme ich zu dem Schluss, dass asymmetrische Vulkankrater eine asymmetrische Verteilung von pyroklastischem Auswurf hervorrufen. Das führt zu einer bevorzugten Richtung für vulkanischen Fallout — und falls es zu einer kollabierenden Ausbruchsäule kommt — zu einer bevorzugten Richtung für pyroklastische Ströme. Der technische Fortschritt durch Drohnen, Photogrammmetrie und 3D Druck bietet einige Chancen für die Vulkanologie. Luftaufnahmen durch Drohnen ermöglichen eine schnelle, günstige und sichere Vermessung von Vulkankratern, auch in Zeiten erhöhter Aktivität. Zusammen mit Photogrammmetrie und 3D Druck lassen sich realitätsnahe Kratergeometrien erzeugen, für zunehmend realistische skalierte Laborexperimente.Volcanic eruptions are among the most violent displays of the Earth’s natural forces and threaten human health and infrastructure. Explosive eruptions are hazardous due to their impulsive and dynamic nature, ejecting gas and pyroclasts at high velocity and temperature into the atmosphere. In recent years, monitoring efforts have increased, but forecasting eruptions is still challenging as volcanoes are complex systems with the potential for inherently unpredictable behaviours. To date, the underlying boundary conditions are beyond observation and quantification. Still, they are constrained by physical laws and can be described through models and experiments. The complexity and interdependency of the parameters governing the dynamics of volcanic eruptions ask for increasingly realistic experiments to investigate the sub-surface conditions driving volcanic eruptions. Above the vent, in the near-vent region, the dynamics of explosive eruptions can first be visually observed. The characteristics at this stage are purely the result of the underlying boundary conditions and the exit (vent) geometry. Volcanic vents are rarely the symmetric features that are often assumed in models and experiments. They often exhibit highly irregular shapes with notched or slanted rims that can be transient. To eventually understand the unobservable boundary conditions, it is necessary to initially gain knowledge about the effect of the observable factors (i.e. vent geometry). This knowledge will ultimately improve the understanding of the parameters affecting an explosive event to develop accurate probabilistic hazard maps. To this end, a combination of field observations and laboratory experiments was used. First, I characterised vent and crater shape changes at a frequently erupting volcano (Stromboli) to collect high-resolution geometric data of volcanic vents and observe the related explosion dynamics. As a result of topographic changes, variable eruption intensity, style and directionality could be detected. Five topographic data sets were acquired by unoccupied aerial vehicles (UAVs) over nine months (May 2019-January 2020). During this period, changes associated with "normal" Strombolian activity, "major explosions" and paroxysmal episodes (3 July and 28 August 2019) occurred. Hence, the topographic data made it possible to link the predominant constructive and destructive processes to these eruption styles. Furthermore, the number and position of active vents changed significantly, which is a critical parameter for hazard assessment as vent geometry and position can be linked to shifts in eruptive mechanisms. These field surveys highlight the geometric complexity and variability of volcanic vents at an unprecedented spatiotemporal resolution. Additionally, the observations of explosions suggested the paramount influence of crater and vent geometry on pyroclast ejection characteristics, a fact that has strong implications for areas potentially affected by bomb impact and pyroclastic fall out. Secondly, I designed a series of shock-tube experiments incorporating the geometry elements observed at Stromboli to quantify the influence of vent geometry and several boundary conditions. These experiments validated the link between vent geometry and explosion dynamics that was observed in the field. The novel geometry element is an inclined exit plane of 5°, 15° and 30° slant angle combined with a cylindrical and diverging inner geometry resulting in six vent geometries. All experiments were conducted with gas-only (Argon) at room temperature, four different starting pressures (5, 8, 15, 25 MPa) and two reservoir volumes (127.4 cm3, 31.9 cm3). Despite the vertical setup, the slanted geometry yielded both a laterally variable gas spreading angle and an inclination of the jets. The inner geometry controlled the jet inclination towards the dip direction of the slanted exit plane (cylindrical) and against the dip direction of the slanted exit plane (diverging). Cylindrical vents produced larger gas spreading angles than diverging vents. Both gas spreading angle and jet inclination were highly sensitive to the experimental pressure and the slant angle. They had a positive correlation with maximum gas spreading angle and jet inclination. Additionally, the pressure was positively correlated with the maximum duration of underexpanded characteristics of the jet. The gas volume only showed a positive correlation with the maximum gas spreading angle. Thirdly, I added particles to the experiments to mimic the ejection of gas-particle jets during explosive volcanic eruptions. For this set of experiments, the two geometries with the 30° slant angle from the previous experimental series were used as they exhibited the strongest effect on the gas ejection dynamics. They were supplemented by a third vent that resembled the "real" geometry of Stromboli’s active S1 vent as it was mapped in May 2019 and fabricated by 3D printing. The S1’s geometry is characterised by a ~ 10° divergence on one side and a ~ 40° divergence on the other side. Besides three vent geometries, two types of particles (scoria and pumice), each with three different grain size distributions (0.125– 0.25, 0.5–1, 1–2 mm) and two starting pressures (8, 15 MPa) were used. The near-vent vent dynamics were characterised as a function of particle spreading angle and particle ejection velocity. The vent geometry governed the direction and the magnitude of particle spreading, and the velocity of particles. All geometries yielded asymmetric particle spreading as well as a non-uniform velocity distribution in experiments with pumice particles. The combination of field observations, gas-only and gas-particle experiments demonstrated the prime control exerted by vent geometry. In nature, a modification of the vent led to modified pyroclast ejection patterns. In the laboratory the complex geometries facilitated inclined gas jets, an asymmetric gas and particle spreading angle, and an asymmetric particle ejection velocity distribution. These findings suggest that the asymmetry of volcanic vents and/or craters can promote the asymmetric distribution of volcanic ejecta.Which, in turn, will lead to a preferred direction of volcanic fallout and — in case a column collapse occurs — to a preferred direction of the ensuing pyroclastic density currents. The availability of new technology like unoccupied aerial vehicles, photogrammetry and 3D printing provides several opportunities for the volcanological community. Aerial observations allow a fast, inexpensive and safe way to collect geometrical data of volcanic vents and craters, even in times of elevated volcanic activity. In combination with photogrammetry and 3D printing, "real" vents can be produced for increasingly realistic scaled laboratory experiments

Recent Developments and Applications of Acoustic Infrasound to Monitor Volcanic Emissions

Volcanic ash is a well-known hazard to population, infrastructure, and commercial and civil aviation. Early assessment of the parameters that control the development and evolution of volcanic plumes is crucial to effective risk mitigation. Acoustic infrasound is a ground-based remote sensing technique—increasingly popular in the past two decades—that allows rapid estimates of eruption source parameters, including fluid flow velocities and volume flow rates of erupted material. The rate at which material is ejected from volcanic vents during eruptions, is one of the main inputs into models of atmospheric ash transport used to dispatch aviation warnings during eruptive crises. During explosive activity at volcanoes, the injection of hot gas-laden pyroclasts into the atmosphere generates acoustic waves that are recorded at local, regional and global scale. Within the framework of linear acoustic theory, infrasound sources can be modelled as multipole series, and acoustic pressure waveforms can be inverted to obtain the time history of volume flow at the vent. Here, we review near-field (<10 km from the vent) linear acoustic wave theory and its applications to the assessment of eruption source parameters. We evaluate recent advances in volcano infrasound modelling and inversion, and comment on the advantages and current limitations of these methods. We review published case studies from different volcanoes and show applications to new data that provide a benchmark for future acoustic infrasound studies.Silvio De Angelis and Alejandro Diaz-Moreno are funded by NERC grant number NE/P00105X/1. Luciano Zuccarello has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 798480

Complex geometry of volcanic vents and asymmetric particle ejection: experimental insights

Explosive volcanic eruptions eject a gas-particle mixture into the atmosphere. The characteristics of this mixture in the near-vent region are a direct consequence of the underlying initial conditions at fragmentation and the geometry of the shallow plumbing system. Yet, it is not possible to observe directly the sub-surface parameters that drive such eruptions. Here, we use scaled shock-tube experiments mimicking volcanic explosions in order to elucidate the effects of a number of initial conditions. As volcanic vents can be expected to possess an irregular geometry, we utilise three vent designs, two complex vents and a vent with a real volcanic geometry. The defining geometry elements of the complex vents are a bilateral symmetry with a slanted top plane. The real geometry is based on a photogrammetric 3D model of an active volcanic vent with a steep and a diverging vent side. Particle size and density as well as experimental pressure are varied. Our results reveal a strong influence of the vent geometry, on both the direction and the magnitude of particle spreading and the velocity of particles. The overpressure at the vent herby controls the direction of the asymmetry of the gas-particle jet. These findings have implications for the distribution of volcanic ejecta and resulting areas at risk

Experimental and numerical studies of whirling fires

Motivation of this study stems from the need to understand the physical mechanisms of whirling fires that occur in an open space and within enclosures. Buoyant whirling flames may be potentially more destructive than ordinary fires due to greater burning rate, higher concentration of heat release in a small region of the plume core, increased radiative output and unexpected smoke movement. The effects of rotation upon the structure and behaviour of buoyant flames have not yet been thoroughly studied and understood. Investigation of this phenomenon is therefore required to allow techniques to be developed that will counter the threat of such outbreaks. Also, the mechanisms controlling the development and stability of whirling flames are of fundamental interest for refined modelling of coherent and self-organised flame behaviour. This work, is an experimental, theoretical and numerical study of whirling fires. Experimental results, a modified CFD model and simulations of whirling flames are presented within this Thesis. The work aims to overcome the limitations of the previous research of whirling fires which is insufficient from both an experimental and theoretical point of view. Firstly, experimental studies of intermediate (room-size) scale whirling fires have not yet been comprehensively reported, despite a great deal of attention devoted to both large scale mass fires and smaller laboratory flames. Experimental studies undertaken using a facility at the Greater Manchester Fire and Rescue Service Training Centre fill this gap, thus demonstrating that whirling flames may develop within a compartment. The periodic precession, formation and destruction of the whirling flame and the increase of the time-averaged burning rate (compared to non-whirling flames in the open space) have been observed. Three fuels with significantly different burning rates (diesel, heptane and ethanol) were investigated in this work. Secondly, previously published results of theoretical analysis of rotating flames were oversimplified and based on strict limitations of the integral model or the inviscid flow assumption. Also there have only been few attempts to undertake CFD modelling of whirling flames. In published studies, radiative heat transfer was not modelled and the burning rate was not coupled with the incident heat flux at the fuel surface. To overcome these limitations, the CFD fire model Fire3D, developed in the Centre for Research in Fire and Explosion Studies, has been adapted to allow numerical simulations of rotating buoyant turbulent diffusion flames. The turbulence model was modified to take into account stabilisation of turbulent fluctuations due to the centrifugal acceleration within the rotating flow. Theoretical analysis of the vorticity equation revealed the physical mechanisms responsible for vorticity concentration and amplification in the rising plume affected by externally imposed circulation. This explains the significant flame elongation (when compared to non-rotating cases) observed in the experiments. Computational results have also been compared to video-recordings of the experimental flames produced; flame elongation was replicated and similar stages of oscillating flame evolution, including formation and destruction of the vortex core, have been identified. Implications of the phenomena studied in relation to fire engineering are also provided. This study contributes to a performance based framework for an engineering approach, which is reliant upon detailed quantitative analysis and modelling. Such an approach is encouraged by modem fire safety legislation including the guides to fire safety engineering BS9999-21 and BS79742 'British Standard 9999-2 Draft Code of Practice for fire safety in the design, construction and use of buildings. BSI, 2004. UK. 2 British Standard BS7974 Application of fire safety engineering principles to the design of buildings. BSI, 2001-2003. UK