Dr Nicholas Walliman

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.

This article examines the criteria for the procedural process that is applied to prevent decay in earthen built heritage conservation, referred to as intervention. When defining criteria for intervention, it was necessary first to establish what needs are required to be addressed and then to define a methodology of intervention while considering indicators of quality and indicators of best practice. The aim is to contribute to a successful conservation approach, in order to better address threats. The research methodology of this investigation was based in a case study strategy using qualitative methods. Data were collected using documentary, questionnaire and interview methods from three sources, the case studies, the stakeholders and a selected group of international key-experts in earthen built heritage conservation. Seven key components were identified for the methodology of intervention and the criteria for intervention were examined through three types of approach: descriptive, evaluative, and prescriptive A serious lack of understanding was found among experts in conservation of the meaning and need for a methodology of intervention in conservation and the meaning or need for devising criteria for conservation intervention.

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.

It is evident that there is no established flood damage prediction tool for individual non-domestic buildings that can account in any detail for their different types of construction. Unlike domestic buildings, non-domestic buildings often feature several different types of construction within the same premises. This absence 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 European Community FP7 project FloodProBE, and presented at the Sustainable City 2012 Conference, discusses the current estimation methods used in the UK, Germany, USA and Australia, and suggests a way to improve on these by devising a tool capable of estimating damage to individual non-domestic buildings. Standard damage and repair parameters are investigated and the major variables are considered – those related to the flood event such as overfloor depth, velocity, rate of rise, debris, contaminants, frequency and duration of inundation and timing, and those relate to the building characteristics, such as structure, construction, materials and their vulnerability to water and drying characteristics, services and their locations. The aims and functions of a prototype flood damage estimation tool are described, including the type of users aimed at, and the method of calculation, input data required and types of output delivered. The model is demonstrated on one case study of an actual building damaged by flooding and the predicted cost compared with the actual cost of reinstatement. A sensitivity analysis is made on the fl ood characteristic inputs. The conclusions contend that that the prototype tool is worth developing to produce a useful way of predicting the costs of flood damage to individual buildings which will enable calculations to be made for assessing the cost–benefit analysis of installing flood mitigation/resilience measures to the building in order to protect it and its contents.

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.

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.

Overheating owing to solar heat gain through in-plane rooflights in industrial shed-type buildings leads to thermal discomfort, increasing demand for artificial cooling and higher energy consumption and carbon dioxide emissions. This paper argues that by using a saw-tooth roof configuration with northlights, overheating in summer is significantly reduced without impairing the quality of daylighting. A comparison of the daylighting and thermal performance of conventional (in-plane) rooflights with a northlight configuration is described, using Lumen Designer for daylighting and TAS (dynamic thermal simulation software) to assess energy needed for heating and cooling. Although daylighting performance of northlights is lower for a given percentage of rooflighting, and heating requirements are 10% higher, the overheating is much reduced. As summer conditions are likely to be increasingly important and heating demand will reduce, it is suggested that modern northlight solutions should be developed.

Most industrial buildings rely almost entirely on air-conditioning systems to provide thermal comfort to staff and customers who use the premises. As an alternative to this active approach, passive strategy is recommended to either fulfil this task or to help reduce energy consumption of air-conditioning systems already installed. Applying solar reflective coatings on external surfaces of the building, a key passive strategy, appears to offer an effective solution to reduce solar heat, especially during the summer, penetrating through the building fabric. This article discusses a study that uses computer thermal modelling to investigate the effectiveness of this strategy and to explore its contribution to operational energy savings. Detailed mathematical modelling in accordance with thermodynamic and heat transfer theories through the building fabric is illustrated and solutions to the mathematical problems are presented. The study consists of a comparison between two scenarios (normal coating and reflective coating) in three locations in China and one in Australia. The application of solar reflective coatings on external surfaces of the building produces energy savings for all the four locations and is found to be more beneficial in hot climates where there is a considerable need to reduce summer solar gains.

The use of multi-foil insulation for building applications, especially in roof structures, has attracted increasing interest because it blocks different heat transfer routes through its multi-layer designs. This is particularly the case with radiative heat transfer, due to the shiny foil layers present on each face and in between insulation layers. However, to date, there is a lack of conformance in the thermal performance of the system between the tests by investigators and the claims made by the manufacturers. This is due to different measuring methods being used and different conditions that are applied. This paper reviews the construction of multi-foil insulation systems and the analyses of their thermal performance as presented by manufacturer and investigators using in situ tests and product tests, and focusing on the different conditions for the tests to be conducted. In addition, the further in situ tests with the considerations of long-term testing, using different weather conditions and exactly identical setup of equivalent teststo show repeated, more convinced and robust results are suggested.

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.

Thin-joint glued brickwork is used increasingly in mainland Europe but the uptake of the technology is inhibited in the UK because of a lack of design guidance. This paper, based on an international research project, provides some essential technical and practical information about thin-joint glued brickwork. The characteristics and advantages of thin-joint glued brickwork are described, latest research and working practices, particularly in The Netherlands and Belgium are reviewed and regulations, including Eurocode 6 are discussed. In relation to site practice, specific training and an adjustment of work practices are required due to differences in comparison to traditional brick construction techniques. A section on detailing and architectural aspects deals with appearance, dimensioning, pointing, expansion joints and other constructional considerations. The suitability of thin-joint techniques for brickwork prefabrication is examined, and lifting and transportation tests on brick panels demonstrated the potential of using prefabrication for production.

Phase change materials (PCMs) can store much larger amounts of thermal energy per unit mass than conventional building materials and can be used to add thermal stability to lightweight construction without adding physical mass. This paper reviews how PCMs could be incorporated in building materials, particularly in passive applications. A simulation study using IES Virtual Environment package ‘Apache’ was carried out on PCM impregnated plasterboard, investigating various fusion temperatures of the PCM during night, day, and week-long test durations in hot weather conditions. Different ventilation rates and alternative conductivity values of the gypsum in the plasterboard were tested. It was shown that use of PCMs has significant advantages for both commercial and residential building applications, provided sufficient night ventilation is allowed.

The properties of insulation materials used in the building envelope have a strong influence on thermal performance of buildings, in particular the U-value of their walls/roofs. This paper summarises current research and developments of vacuum insulation panels (VIP), which provide a quantum leap forward in thermal insulation, offering exciting opportunities for both new and retrofitted buildings. Use of VIP not only provides excellent thermal performance to meet the requirements of building regulations, as well as offering a great potential to reduce energy consumption in buildings, but also increases the available internal area of buildings. However, a real indication of overall thermal performance in use must take into account the thermal bridging that occurs around the edges of the panel caused by the construction details. The performance is also dependent on the maintenance of a vacuum against the influences of envelope permeability, outgassing, moisture and physical damage. More research and development is needed in the practical application of VIP in building solutions.