Informal Settlement Dwellings Research Articles

The Effect of the Fuel Location and Ventilation Factor on the Fire Dynamics of Informal Settlement Dwellings

AbstractThree full-scale experimental compartment fires are compared to investigate the effect of the fuel location and the ventilation factor on under ventilated thermally thin bounded ISO-9705 compartments. Wood cribs were used as the fuel load and the crib placement was varied between two locations (back and middle) to study the effect of the fuel location. Furthermore, the ventilation conditions were changed from a door and window (i.e., ventilation factor of 2.58 m5/2) to only a door (i.e., ventilation factor of 2.26 m5/2) for the scenario where the cribs were placed at the back of the compartment. The novelty of this work lies in its examination of the time to flashover, gas layer temperature, heat release rate, and external radiative heat fluxes, specifically considering the impact of fuel location and ventilation factor. It was observed that placing the fuel package in the middle of the compartment led to a longer growth phase, hotter gas layer temperature, a higher Heat Release Rate (HRR) needed for flashover ($$\dot{q}_{fo}$$ q ˙ fo ), and higher external radiative heat fluxes through openings. It was also found that, decreasing the ventilation factor decreased the heat losses and therefore the $$\dot{q}_{fo}$$ q ˙ fo . Decreased ventilation also affected the height of the neutral plane, as one would expect, and the shape of the external plume, but did not have significant effect on the temperature within the compartment, the walls of the compartment, and the external radiative heat flux.

Investigating Numerically the Effect of Wind on Fire Spread Between Two Informal Settlements Dwellings

AbstractPrevious full-scale fire studies revealed that the role of wind on fire spread between informal settlement dwellings was critical. However, the influence of wind conditions on informal settlement dwellings fire spread is currently understudied in the literature. This study aimed to investigate the effect of external wind conditions on fire spread between two informal settlement dwellings with a distance of 1 meter between them. A parametric numerical analysis was performed using the computational fluid dynamics code Fire Dynamics Simulator. The numerical models were benchmarked through laboratory experiments. The investigation included an analysis of the fire spread mechanism, flashover conditions, and heat transfer processes at the boundaries of the dwellings. Simulations were conducted with burning wood cribs as fuel and three wind speeds (6 m/s, 10 m/s, and 14 m/s) with four wind directions (East, West, South, and North). Results showed that wind speed and direction had a significant impact on the fire dynamics of the origin dwelling and its spread to neighboring dwellings. The wind direction also influenced the time to flashover in both dwellings, with a delay observed when the wind flowed through the alley between the two dwellings. The total heat transfer coefficient was found to be directly proportional to the wind speed for all directions. The internal radiative heat transfer coefficient of one wall was found to represent the total heat transfer coefficient in different scenarios. This study highlights the complexity of determining the role of wind in urban fire spread and underscores the need for further research in this area.

Numerical Study on the Effect of Atmospheric Wind on the Fire Severity in Informal Settlements with Different Dwellings’ Wall Thermal Characteristics

AbstractThere is a persistent risk of large-scale fire conflagrations in informal settlements, which can threaten hundreds of people simultaneously. Although the literature implies that wind conditions have a significant impact on these fires, little is known about how wind conditions affect the dynamics and spread of flames in informal settlements. In order to comprehend the impact of wind conditions (speed and direction) on the time to flashover and fire severity in informal settlement dwellings with different wall thermal characteristics, a numerical study was conducted utilizing the Fire Dynamics Simulator (FDS), a Computational Fluid Dynamics (CFD) code. For six different wind speeds (1 m/s, 5 m/s, 10 m/s, 15 m/s, 20 m/s and 25 m/s) and two wind directions (side and back wind). Simulations were conducted with full-scale informal settlement dwellings burning wood cribs, analyzing the fuel mass loss rate, hot gas temperature, global equivalence ratio, radiative heat flux outside the door, and time to flashover. In addition, the influence of wall thermal properties was examined for thermally-thin steel-clad and asbestos cement-clad dwellings (thermally-thick). Regardless of wind direction, it was noticed that an increase in wind speed significantly shortened the time required to attain flashover. This was shown to be the result of the wind accelerating the burning rate of the wood cribs and, as a result, the faster temperature rise of the hot gas. Radiative heat fluxes observed outside the door increased with the wind speeds. The direction of the wind had a small effect on the investigated fire characteristics, with the side wind scenarios exhibiting somewhat longer timeframes to flashover. Thermally-thin walled informal settlement dwellings exhibited a greater fire severity, with higher fuel mass loss rates, hot gas layer temperatures, and higher external radiant heat fluxes, as well as shorter timeframes to flashover. These findings indicate that both wind speed and thermal wall characteristics have a substantial impact on the severity of fires in informal settlements and can enhance the risk of fire spread.

Reduced Scale Experiments on Fire Spread Involving Multiple Informal Settlement Dwellings

Fire disasters in informal settlements (also referred to as slums, shantytowns, favelas, etc.) are a major challenge worldwide, with a single incident being able to displace thousands of people. Numerous factors including dwelling spacing, material type, topography, weather, fuel loads, roads, and more influence fire spread. Conducting large-scale experiments to quantify and understand these phenomena is difficult and costly. Hence, it would be beneficial if Reduced Scale Experiments (RSE) could be developed to study the influence of these phenomena. Previous research has demonstrated that a 1/4th scale informal settlement dwelling (ISD) RSE can sufficiently capture the fire behaviour and fire dynamics within dwellings. The objective of this work is to develop a methodology for multi-dwelling ISD scaling such that large-scale spread phenomena can be captured. This paper carries out a series of RSEs to study the influence of (a) the number of dwellings, (b) orientation of dwellings, windows, and door openings, (c) cladding material, (d) wind effects, (e) the distance between dwellings and (f) fuel load on spread. Results are compared to previous large-scale experiments. It is shown that the geometric scaling of distance between dwellings is suitable for capturing spread. It was found that wind and the fuel load contribute significantly to the fire spread, but the type of cladding, distance between dwellings, dwelling orientation, and type of structural members used also affects fire spread rates. The comparative results with full-scale experiments (FSEs) shows that the peak temperatures were comparable and had similar profiles. A good correlation exists between FSEs and RSEs in terms of fire dynamics and spread characteristics, but the spread time (scaled or unscaled) does not correlate well with FSEs. Further work is needed before the work can be reliably used for predicting multi-dwelling spread, especially when wind is involved, due to the complex interaction of parameters and difficulty in scaling flame impingement.

Laboratory experiment of fire spread between two informal settlement dwellings

Fire spread between informal settlement dwellings (ISD) is a primary concern for large scale informal settlements conflagrations. Globally, approximately one billion people live in informal settlements and are exposed to these fires. This paper presents a fire spread experiment between two dwellings, built with ISO 9705 dimension as an approximation of an ISD and separated by 1 m. The fire development and fire spread mechanisms within and between the ISDs were investigated and benchmarked against an independent single dwelling experiment with identical boundary conditions. Parameters, such as mass loss rate of fuel, total heat release rate, gas temperatures, wall and roof temperatures, and gas velocity at the openings were measured, as well as external incident heat fluxes. A comparison between the single and double dwelling experimental results are made. It was established that the existence of the adjacent dwelling, which changes the dynamics of initial burning stage of the wood cribs in dwelling, delayed the flashover of the burning dwelling by more than 150 s (Dwelling 1). The fire spread from dwelling to dwelling that is perpendicular to the plane of the openings is hypothetically concerned with wall collapse or large flame ejections from the burning cardboard linings, rather than the radiation from the heated metal wall, with recorded fluxes of 35, 20, and 5 kW/m2, respectively. Due to the very thin-walls with high conductivity and natural leakage in ISDs, current theories for temperatures, heat release rates, flame shapes, and flashover conditions, based on thermally thick-walled dwellings, do not replicate the data well. A new fire spread model between dwellings, based on accumulated energy, is proposed in this work and conservatively under-predicts the time to ignition by 9 % for this experiment.

Experimental and Numerical Study for the Effect of Horizontal Openings on the External Plume and Potential Fire Spread in Informal Settlements

According to recent UN reports, it is estimated that more than one billion people live in informal settlements globally, exposing them to a large potential fire risk. In previous research, it was found that the main fire spread mechanism between dwellings is the external flaming (plume) and radiative heat fluxes from the vertical openings at the dwelling of origin to the surroundings. In this paper, an experimental and numerical study was conducted to quantify the effect of adding horizontal roof openings to the design of informal settlement dwellings to reduce the fire spread risk by decreasing the length of flames and radiation from the external plumes at the vertical openings. In total, 19 quarter scale ISO-9705 compartment fire experiments were conducted using an identical fuel load (80 MJ/m2) of polypropylene and were used to validate a physical computational fluid dynamics model for future studies. Five different total horizontal openings areas (0.0025, 0.01, 0.04, 0.09, and 0.16 m2) were investigated using two horizontal openings designs: (1) four square openings at the four corners of the compartment and (2) one slot cut at the middle of the compartment. It was found that adding horizontal openings decreased the average heat flux measured at the door by up to 65% and 69% for corner and slot cases, respectively. Heat flux reductions were achieved at opening areas as low as 0.01 m2 for slot cases, whereas reductions were only achieved at areas of at least 0.09 m2 for corner cases. The Computational Fluid Dynamics (CFD) model was validated using the experimental results. It successfully captured the main fire dynamics within the compartment in addition to the values of the external radiative heat flux. Further, a new empirical ventilation factor was generated to describe the flow field through both openings configurations which showed strong coupling with the inlet mass of fresh air to the compartment.

Modelling the Effects of Boundary Walls on the Fire Dynamics of Informal Settlement Dwellings

Characterising the risk of the fire spread in informal settlements relies on the ability to understand compartment fires with boundary conditions that are significantly different to normal residential compartments. Informal settlement dwellings frequently have thermally thin and leaky boundaries. Due to the unique design of these compartments, detailed experimental studies were conducted to understand their fire dynamics. This paper presents the ability of FDS to model these under-ventilated steel sheeted fire tests. Four compartment fire tests were modelled with different wall boundary conditions, namely sealed walls (no leakage), non-sealed walls (leaky), leaky walls with cardboard lining, and highly insulated walls; with wood cribs as fuel and ISO-9705 room dimensions. FDS managed to capture the main fire dynamics and trends both qualitatively and quantitatively. However, using a cell size of 6 cm, the ability of FDS to accurately model the combustion at locations with high turbulent flows (using the infinitely fast chemistry mixing controlled combustion model), and the effect of leakage, was relatively poor and both factors should be further studied with finer LES filter width. Using the validated FDS models, new flashover criteria for thermally thin compartments were defined as a combination of critical hot gas layer and wall temperatures. Additionally, a parametric study was conducted to propose an empirical correlation to estimate the onset Heat Release Rate required for flashover, as current knowledge fails to account properly for large scale compartments with thermally thin boundaries. The empirical correlation is demonstrated to have an accuracy of ≈ ± 10% compared with the FDS models.

Determination of Critical Separation Distance Between Dwellings in Informal Settlements Fire

Approximately one billion people across the globe are living in informal settlements with a large potential fire risk. Due to the high dwelling density, a single informal settlement dwelling fire may result in a very serious fire disaster leaving thousands of people homeless. In this work, a simple physics-based theoretical model was employed to assess the critical fire separation distance between dwellings. The heat flux and ejected flame length were obtained from a full-scale dwelling tests with ISO 9705 dimension (3.6 m × 2.4 m × 2.4 m) to estimate the radiation decay coefficient of the radiation heat flux away from the open door. The ignition potential of combustible materials in adjacent dwellings are analyzed based on the critical heat flux from cone calorimeter tests. To verify the critical distance in real informal settlement fire, a parallel method using aerial photography within geographic information systems (GIS), was employed to determine the critical separation distances in four real informal settlement fires of 2014–2015 in Masiphumelele, Cape Town, South Africa. The fire-spread distances were obtained as well through the real fires. The probabilistic analysis was conducted by Weibull distribution and logistic regression, and the corresponding separation distances were given with different fire spread probabilities. From the experiments with the assumption of no interventions and open doors and windows, it was established that the heat flux would decay from around 36 kW/m2 within a distance of 1.0 m to a value smaller than 5 kW/m2 at a distance of 4.0 m. Both experiments and GIS results agree well and suggest the ignition probabilities at distances of 1.0 m, 2.0 m and 3.0 m are 97%, 52% and 5% respectively. While wind is not explicitly considered in the work, it is implicit within the GIS analyses of fire spread risk, therefore, it is reasonable to say that there is a relatively low fire spread risk at distances greater than 3 m. The distance of 1.0 m in GIS is verified to well and conservatively predict the fire spread risk in the informal settlements.

The Effect of Separation Distance Between Informal Dwellings on Fire Spread Rates Based on Experimental Data and Analytical Equations

Globally, the number of informal settlement dwellings are increasing rapidly; these areas are often associated with numerous large fires. Unfortunately, until recently, very little research has been focused on informal settlement fire issues leaving any attempts to improve their fire safety lacking the evidence base to support effective-decision making. However, over the past 4 years, a limited number of researchers have looked at better understanding these fires through full-scale experimentation and numerical modelling; starting to provide the necessary evidence base and future research directions. It is with this background in mind that this paper seeks to provide a more fundamental understanding of the effect of dwelling separation distance on informal settlement fire spread based on full-scale experiments and analytical equations. In this paper two full-scale experiments were conducted. Both experiments consisted of multiple dwellings, with the main difference between the experiments being the separation distance. Fire spread times, heat release rates, door and window flow velocities, ceiling temperatures and incident heat fluxes were recorded and are reported for both experiments. Theoretical neutral planes are derived and compared to the experimental neutral planes, which show relatively good correlation. The paper continues by calculating the expected incident radiation and time-to-ignition, using the flux-time product method, of the two fire scenarios (i.e., the two experiments) through means of analytical equations, and these findings are compared to the experimental results. Through configuration factors, the paper shows the effect of separation distance, dwelling height and dwelling length on the times-to-ignition, where it is clear that the heat flux received by an adjacent dwelling decrease approximately exponentially as the distance between dwellings increases, and consequently, the time-to-ignition increases exponentially as the separation distance between dwellings increases.

TOWARDS A SUSTAINABLE AND CONTEXT-BASED APPROACH TO ANTI-SEISMIC RETROFITTING TECHNIQUES FOR VERNACULAR ADOBE BUILDINGS IN COLOMBIA

Abstract. In Colombia earthen buildings, mostly adobe, makes up 80% of the national monumental heritage and historic urban centres. Moreover, vernacular earthen techniques have been largely used for dwellings in rural villages, small towns or informal settlements and represent, nowadays, a huge architectural and cultural heritage of the country. Due the brittle behaviour and low ductility of the building material, characterized by both low tensile and bending strength, earth constructions show high seismic vulnerability; nevertheless, though Colombian earthquake hazard level is considered very high, current national seismic building regulations do not include any reference to earthen architecture. Seismic failure mechanisms most frequently occurring to masonry architecture, as adobe buildings rehabilitation techniques and seismic behaviour improvement practices, have been widely published. This paper aims to investigate possible causes associated to failure mechanisms due to common adobe building practices in Colombia and intervention strategies, to be eventually implemented in order to reduce risks. The paper focuses on strategies and technologies for seismic retrofitting, while evaluating their effectiveness and feasibility through ‘sustainability’ indicators, based on literature quantitative and qualitative data, and strictly related to rural Colombian economic, social and environmental conditions, where available resources are scarce and labour often not qualified.

A full-scale experimental study on single dwelling burning behavior of informal settlement

Approximately one billion people globally live in informal settlements with a large potential fire risk, where a single dwelling fire may result in a very large urban conflagration leaving hundreds, if not thousands, of people homeless. What is not well understood, however, is how fires in informal settlement dwellings develop and spread, and what influence the dwelling boundary has on these two areas. In this work, four different real-scale compartments were constructed and ignited under a large fire calorimeter hood. The cases include a typical thin metal-walled dwelling (baseline), a no leakage dwelling, a dwelling lined with cardboard and a dwelling with highly insulated walls. The fuel locations, fuel loads of 25 kg/m2, ignition method and ambient conditions were kept identical in four experiments. Important parameters of compartment fire development, such as heat release rate, gas temperatures, fuel mass loss rate, wall and ceiling temperature were recorded. To investigate the fire spread mechanism between dwellings, the incident radiation heat flux around the dwellings and projection flame length were measured as well. It was found that the boundary conditions in informal settlement significantly affect the fire dynamics and fire spread of informal settlement, and that current analytical/empirical equations are not capturing accurately experimental observations.

Novel Coronavirus in Cape Town Informal Settlements: Feasibility of Using Informal Dwelling Outlines to Identify High Risk Areas for COVID-19 Transmission From A Social Distancing Perspective.

BackgroundThe challenges faced by the Global South during the coronavirus disease (COVID-19) pandemic are compounded by the presence of informal settlements, which are typically densely populated and lacking in formalized sanitation infrastructure. Social distancing measures in informal settlements may be difficult to implement due to the density and layout of settlements. This study measures the distance between dwellings in informal settlements in Cape Town to identify the risk of COVID-19 transmission.ObjectiveThe aim of this paper is to determine if social distancing measures are achievable in informal settlements in Cape Town, using two settlements as an example. We will first examine the distance between dwellings and their first, second, and third nearest neighbors and then identify clusters of dwellings in which residents would be unable to effectively practice social isolation due to the close proximity of their homes.MethodsDwellings in the settlements of Masiphumelele and Klipfontein Glebe were extracted from a geographic information system data set of outlines of all informal dwellings in Cape Town. The distance to each dwelling’s first, second, and third nearest neighbors was calculated for each settlement. A social distance measure of 2 m was used (buffer of 1 m, as dwellings less than 2 m apart are joined) to identify clusters of dwellings that are unable to effectively practice social distancing in each settlement.ResultsThe distance to each dwelling’s first 3 nearest neighbors illustrates that the settlement of Masiphumelele is constructed in a denser fashion as compared to the Klipfontein Glebe settlement. This implies that implementing social distancing will likely be more challenging in Masiphumelele than in Klipfontein Glebe. However, using a 2-m social distancing measure, it was demonstrated that large portions of Klipfontein Glebe would also be unable to effectively implement social distancing.ConclusionsEffectively implementing social distancing may be a challenge in informal settlements due to their density. This paper uses dwelling outlines for informal settlements in the city of Cape Town to demonstrate that with a 2 m measure, effective social distancing will be challenging.

Towards a simplified fire dynamic simulator model to analyse fire spread between multiple informal settlement dwellings based on full‐scale experiments

SummaryThis paper develops a Fire Dynamics Simulator (FDS) model to analyse fire spread for informal settlements, based upon full‐scale experiments. Informal settlements are frequently ravaged by fires, leaving thousands of people homeless, and with more than 1 billion people residing in informal settlements, there is a significant need to understand and improve the fire safety in such areas. Due to high levels of uncertainty inherent with input parameters regarding informal settlements, this work also investigates the sensitivity of fire behaviour to the input parameters used in numerical simulations. It is shown that spread times between two dwellings can vary from 1 minute after flashover to no spread at all, depending on the simulation input parameters selected. This paper highlights the importance of such input parameters when trying to model fire spread between dwellings. The simulations indicate that a simplified fire spread model for informal settlements is possible, especially for steel clad dwellings, however it showed that significant work is required for timber clad dwellings, that is, because the rate at which additional ventilation forms in the simulation for the timber clad dwellings is significantly slower than reality, which is as a result of the simplifications made. The simplification of using heating, ventilation, and air conditioning (HVAC) systems to model leakages, resulting from the corrugated flutes, showed good enclosure fire dynamics behaviour compared to the experiments, but created new challenges with regards to the spread mechanism, since HVAC systems do not allow electromagnetic waves to penetrate in the same manner as an opening.

Proximal design in South African informal settlements: users as designers and the construction of the built environment and its fire risks

ABSTRACT Informal settlements present a challenge for fire safety because they lack the regulation of building standards that have been central to reducing fire risks elsewhere. Rather than being the product of specialist designers (such as architects and engineers), constrained by regulation, informal settlement dwellings are instead predominantly the work of their occupants. Thus, the design and construction of informal settlement structures can be understood as a result of proximal design by the residents themselves – drawing on the concept proposed by Usenyuk et al. in their 2016 paper “Proximal Design: Users as Designers of Mobility in the Russian North.” This paper applies, and critiques, the proximal design concept through a focus on the informal settlement fire problem in South Africa. Our case study points to weaknesses in the way that Usenyuk et al. apply the concept of proximal design. Not only do Usenyuk et al. emphasize that proximal design involves mastery of a severe environment, but they also fail to give sufficient attention to the social context. Although a focus on proximal design provides insights into the informal settlement fire problem, it is vital that the focus on proximate activities does not obscure the importance of broader societal factors.

Development of a full-scale testing methodology for benchmarking fire suppression systems for use in informal settlement dwellings

Informal settlements (also referred to as slums, shantytowns or squatter camps) are expanding at a rapid rate with more than a billion people currently residing in informal settlements worldwide. The dwellings within these communities are often constructed from readily available materials, making them susceptible to large conflagrations. Within the South African context, there is significant political pressure on governmental agencies to develop and implement interventions to suppress informal settlement fires. However, many proposed solutions lack a sound scientific validation. This paper proposes a full-scale fire testing methodology for benchmarking various suppression systems against each other, using a representative informal settlement dwelling. The aim of the methodology is to assist decision-making when assessing which interventions will be most suitable in post-flashover informal settlement fires. The testing methodology can be carried out without the need for sophisticated equipment, making it readily available to fire brigades and municipalities. In this work a total of nine experiments were conducted which included: brigade-based, community based as well as non-water-based interventions. It was observed that the water-based interventions typically outperformed the remaining interventions, since they suppressed the fire while simultaneously providing a cooling effect, thereby lowering the temperature within the dwelling below the auto-ignition temperature of the fuel, thus preventing re-ignition from occurring. A model is proposed for comparing the efficacy of products based upon the analytical hierarchy process. The results from these types of tests could be adopted as a decision-making tool by the respective authorities thereby potentially preventing costly investments in products that are not suitable for the cause.

Full-Scale Informal Settlement Dwelling Fire Experiments and Development of Numerical Models

While fire-related injuries and deaths decreased in the global north over the past few years, they have increased in the global south. With more than one billion people residing in informal settlements (sometimes known as slums, ghettos or shantytowns), it is necessary that greater effort be placed on addressing and developing means for improving fire safety in these areas. As a result of advances made in computer technologies, emerging performance-based regulations and an increase in building complexity in the global north, the use of computer models simulating enclosure fires have increased dramatically. In this work an experimental investigation is presented for (a) a full-scale corrugated steel sheeting clad informal dwelling experiment and (b) a full-scale timber clad informal dwelling experiment. The experimental results are then compared to numerical models consisting of both simple two-zone (OZone) and computational fluid dynamic models. Currently, there is negligible literature available on Fire Dynamic Simulator (FDS) modelling of informal settlement dwellings (sometimes known as shacks or shanties) fires. This paper evaluates the plausibility of using FDS v6.7 and zonal models to predict certain fire parameters (i.e. ceiling temperatures, heat fluxes, etc.) for Informal Settlement Dwellings (ISDs) and to study the plausibility of using FDS to estimate the probability of fire spread. In this paper an introduction to ISDs is given with details pertaining to construction materials and considerations needed for numerical modelling of informal dwellings (i.e. thin permeable boundaries or combustible boundaries). Models are based upon (a) a prescribed heat release rate per unit area in FDS using data obtained from a Fire Propagation Apparatus test, and (b) an empirical two-zone model using OZone. The FDS validation guide was used to quantify the model uncertainties in order to give a critical separation distance at which fire spread between dwellings will not occur. It was found that at 3 m spacing between ISDs there is a 6% chance (based on the model uncertainties) that fire spread can occur. This is an important finding that highlights the danger associated with these closely spaced dwellings and the hope is that it can guide local government and Non-Governmental Organizations in future decision making. Three meters spacing between dwellings, however, may not be possible due to the socio-cultural-political-economic issues associated with informal settlements. This is one of the first papers to demonstrate FDS models against full-scale ISD experiments.

Experimental study of fire spread between multiple full scale informal settlement dwellings

Internationally, informal settlements (also known as slums, favelas, shantytowns, ghettos, etc.) are expanding rapidly which have been associated with numerous large fires (where more than 10,000 people can be left homeless in a single disaster [1]), and an increase in fire related injuries and deaths. As a result of an increase in fire related incidences, various proposed interventions have been funded from governmental or private sources. However, many interventions have been unsuccessful because of technical, political, economic, social or practical issues. It is with the above mentioned in mind that this paper seeks to provide an understanding of fire behavior between multiple informal settlement dwellings (ISDs) as a baseline for future research and experiments. The paper starts by defining informal settlements in terms of construction and continues to look at the potential causes and hazards associated with informal settlement fires. The following two full-scale informal settlement dwelling burn experiments were conducted; (a) three ISDs clad with steel sheeting and (b) three ISDs clad with timber. The heat fluxes and temperatures of both experiments are shown and compared to understand the effect of cladding materials (i.e. timber cladding versus steel cladding, which are mostly used in informal settlements) on fire spread. Some general behavioral observations made during the full-scale experiments are given and discussed (i.e. how fire spreads, collapse mechanisms, etc.). Fire spread times are reported for both experiments, and range between 4 and 9 min (i.e. from the start of flashover in the first dwelling to the end of flashover in the last dwelling). These experiments are one of the bigger ISD experiments conducted to date and are the first experiments that measured heat fluxes for ISDs, which is crucial to understand fire spread. An important finding in this paper is that there is a critical separation distance of 3.8 m needed to prevent fire spread between dwellings.

Informal settlement fires in South Africa: Fire engineering overview and full-scale tests on “shacks”

This paper discusses fires in informal settlements (otherwise known as slums, ghettos, shantytowns, etc.), which are regularly ravaged by fire in South Africa. Initially an overview of the problem is presented, highlighting the factors that contribute to the frequent, large conflagrations that occur. Details have been based on research conducted in Cape Town, South Africa, although the research is applicable to settlements worldwide. Data from recent fires where up to 4500 people were left homeless is included, highlighting aspects regarding fire spread and fire dynamics. Thereafter, preliminary results from a pilot study are presented where full-scale burn tests have been carried out on informal settlement dwellings, or “shacks”. Results from (a) a smoldering fire test, (b) 25kg/m2 wood fire load test and (c) a ‘representative’ shack fire test are presented. For flaming fires it is shown that flashover in these small dwellings can occur in as little as one minute (depending on the fuel source), which is consistent with observations from professional firefighters in the field. Photoelectric smoke detectors, ionization, and rate-of-rise heat detectors were included during fire tests, to evaluate their performance in such confined spaces, as these are currently being either used or being considered for use in settlements. Activation times are reported for the different tests conducted.

Results of an evaluation of augmented reality mobile development frameworks for addresses in augmented reality

Addresses displayed on dwellings and buildings play a key role in society. Amongst others, they are used for deliveries, in household surveys, to navigate, or to find friends. Sometimes, address signs are destroyed, displaced or illegible, for example, as a result of vandalism, disasters, or poor maintenance. In augmented reality, computer-generated information is superimposed onto a live view of the real world. When address signs are not available, displaying the address in augmented reality could be immensely useful. The research presented in this article is part of a larger research endeavour to investigate augmented reality for addressing. This article presents the results of an evaluation of augmented reality mobile development frameworks for the implementation of a mobile application that displays addresses in augmented reality. Firstly, the requirements for addresses in augmented reality were identified. Three use cases informed these requirements: disaster relief, e.g. address signs are destroyed by an earthquake; household surveys, e.g. locating dwellings in informal settlements or rural areas where addresses are not assigned in any specific sequence and signs do not exist; and address data quality management, e.g. validating digital address data against addresses displayed in the physical world. Due to procurement challenges in the use cases, open source licensing and integration with open source products was identified as an important requirement. The internet was searched and a list of augmented reality mobile development frameworks was compiled. Based on the requirements, the list was shortened to seven frameworks, which were evaluated against a set of criteria informed by the requirements. The evaluation results can guide developers in choosing a framework best suitable for their specific needs and/or for integration with open source products.

A Spatial Perspective of the Patterns and Characteristics of Main- and Substream Migration to the Western Cape, South Africa

This article provides a contemporary spatial perspective of patterns and trends in migration to the Western Cape during the period 2001 to 2011 and contributes an important new perspective on one of the dominant migration streams in South Africa. It applies the concepts of mainstream and substream migration from the differential urbanisation model to analyse characteristics and patterns normally hidden by aggregated migration data. The findings confirm the continuation of strong primary migration streams between the Eastern Cape and municipalities in the Western Cape driven mainly by productionism. These migrants are mostly unmarried, young (25–29 years), mostly unemployed or not economically active, with low incomes. A significant proportion (31.3 %) end up living in informal dwellings in backyards or informal settlements largely concentrated in the provincial primary city, Cape Town. A smaller but prominent substream of migrants to the province consists of affluent, highly skilled, mostly married migrants from other metropolitan cities in South Africa, many from Gauteng. These migrants are driven by environmentalism, and favour Cape Town and adjacent municipalities as their destination—particularly those areas along the south coast of the province containing intermediate-size cities. These identified migration patterns and characteristics hold important development implications at both provincial and municipal levels.