In the south of Algeria, many indigenous settlements have been built using local earth construction techniques, whilst in the north, despite the availability of suitable earth, only a few rural contemporary settlements have been built using ‘improved’ earth construction. This paper adopts a case study approach to examine and compare structural deficiencies of two earth-built housing settlements in different regions in Algeria. In the indigenous earth settlement in the south, where adobe was used in combination with local timber and stones, the dwellings exhibited many structural defects. Stabilisation of the soil and introduction of modern materials in the contemporary rammed earth settlement in the north, have not however helped produce structurally adequate dwellings. These also exhibited many cracks and de-bonding of rendering, and thus not fulfilling the requirements and aspirations of their occupants. The study concludes for a potentially successful earth building scheme there are inter-related factors that should be considered, including: selection of appropriate soil and construction technique, implementing suitable design, construction and post completion processes, availability of relevant skills and provision of adequate training on the construction technique.
An overview is presented of recent advances in the assessment methods and mitigation solutions for the performance of critical buildings during flood events. This draws on research focusing on critical urban infrastructure, which is defined as assets that are essential for the continuity of economic activities in cities and for the basic living needs of the urban population. These assets include networks as well as buildings, the latter (termed ‘critical buildings’) having an important role in protecting equipment and personnel associated with the networks. Examples include power stations, transport control centres, communication hubs, fire stations, shelters and hospitals. Unlike domestic constructions, due to their specificity, these buildings cannot easily be categorised in terms of type of construction or age, and have to be treated as individual buildings. Three methods are presented as a framework with a logical progression for the assessment of building flood vulnerability and the identification of improvement measures: the ‘quick scan’ method, the ‘selection and evaluation tools for flood proofing of buildings’ and the ‘individual building flood damage tool’ (IBT). It is expected that building owners, insurance companies, local authorities and agencies with urban flood management responsibilities will benefit from the application of the framework and tools presented.
Rooflights have become the common installations for industrial buildings to meet both the human health requirements for natural light and the need to save artificial lighting energy, especially for retail or distribution sheds that have big roof to floor area ratios and limitations of using glazing on side elevations. Since almost all of these buildings normally operate during daytime, an opportunity exists to save lighting energy by fitting automatic artificial lighting control. However, due to solar gains through the rooflights, the buildings are vulnerable to summer overheating. If overheating occurs regularly or over sustained periods, it will lead to the need for mechanical cooling, which inevitably results in more operational energy consumption in addition to the initial installation cost. To remedy this potential problem, natural ventilation through ridge openings is explored in this paper because it consumes almost no extra operational energy. Thermal modelling is therefore implemented with focus on influences of lighting control on energy consumption and effects of natural ventilation on reducing overheating. The modelling results indicate that lighting control can save lighting energy by 70% and the use of both ridge ventilation and lighting control can reduce overheating hours considerably, as internal heat is dissipated through the ridge openings and lighting heat gains are cut. In addition, converted from lighting and heating energy used, the overall CO2 reduction can reach 45% when both lighting control and ridge ventilation are applied. The findings from the study would encourage the use of rooflights for industrial buildings and would provide guidance on how to save operational energy while ensuring the thermal comfort inside the buildings.
The paper compares the effect of metal or tiled roofing finishes on the thermal performance of roofs of residential buildings in different climatic conditions in Europe and their contribution to the heat island effect in cities. A typical masonry house with U-values according to national requirements for four different locations in Europe was modeled using IES TAS simulation software. Metal roofs, particularly with reflective coatings, reduce cooling loads or decrease hours overheating more than tiled roofs. Metal roofs reduce heat stored in the building fabric - a major contributor to urban heat islands. With solar reflective coatings, they also reduce summertime surface temperatures during the day.
The likelihood that buildings will be flooded and the frequency and severity of the inundation are calculated as part of the general flood predictions for urban and other areas. However, there is no reliable method to estimate the vulnerability of an individual building to damage from flooding. This makes it difficult for building owners and designers to calculate what appropriate measures should be taken to enhance resilience against floods.This paper, developed in the context of the current EC FP7 project FloodProBE, discusses the current estimation methods used in the UK, Germany, USA and Australia, and suggests ways to improve on these to make a model capable of estimating damage to individual buildings, particularly non-domestic ones. Flood damage to buildings and contents are dependent on a number of variables in relation to the flood events.The major variables are over-floor depth, velocity, rate of rise, debris, contaminants, frequency and duration of inundation and timing. Other variables relate to the building characteristics, such as structure, construction, materials and their drying characteristics, services and their locations, and the condition of the building prior to being flooded. A flood damage estimation tool that can deal with all these variables is likely to be very complex and difficult to manage, though oversimplification of the variables is likely to lead to inaccurate estimations.A balance must therefore be drawn between excessive complexity and accuracy. The output of the model should express the damage in cost form to be consistent with existing damage methodologies. This will enable calculations to be made in order to assess the cost/benefit analysis of installing flood mitigation/resilience measures to the building and/or its surroundings.
A typical modern portal frame warehouse building with in-plane GRP rooflights was modelled using Tas and Lumen Designer software to assess annual heating loads and summertime thermal comfort in the south of the UK. The effects of rooflight area, ventilation strategy and stratification were assessed. Various combinations of ventilation strategy to reduce internal temperatures were investigated both natural and mechanical. The"base case" building incorporated 10% rooflights; the effects of 14%, or no rooflights were investigated. Overheating occurred for the unventilated base case but introducing natural ventilation avoided overheating. The areas of rooflight were not a significant factor. Mechanical ventilation was less effective than open cargo doors in conjunction with ridge vents. Buildings with higher internal heat loads risk overheating unless alternative precautions are taken.