The impact of procurement methods on delivering environmentally sensitive buildings

In the UK, new building regulations (‘Part L2006’) to reduce energy consumption and carbon dioxide emissions within the built environment came into force in 2006. It is now mandatory that all new built and refurbished buildings demonstrate compliance with ‘Target Carbon Emissions Rates’ in the design phase. This has prompted some interesting questions concerning their procurement. Under traditional UK procurement arrangements, designs are, in theory, completed before the contractor becomes involved. However, there has been a significant increase in the use of Design-and-Build procurement: a system which actively supports concurrency in design, procurement and construction. Under such arrangements, the design of environmentally sensitive buildings may be seen as a challenging task, as the iterations required are at odds with the contractor’s incentive to avoid delays and extra cost. This has prompted a preliminary investigation into the opportunities and limitations afforded by different procurement methods for delivering environmentally sensitive buildings. Although these issues are fairly ubiquitous throughout the various building elements, the particular focus was on façade design and construction. Data collection was by structured questionnaire and interviews carried out with large construction companies, architectural practices and building performance consultants. There was a consensus that Part L2006 has major implications for procurement and that compliance is a major step change. A new and indispensable bidding document, the ‘Building Energy Model’, will emerge and in its absence most contractors would decline invitations to bid. There will be an impact on procurement, probably in the form of an extension of the use of ‘novation’. Design-and-Build contractors will ‘freeze’ designs earlier, and forgo the potential for later value engineering in order to avoid risks, which they see as significant. Finally, despite the industry’s ‘fear’ of Part L2006, the regulation has already created a welcome by-product in the form of a clear increase in collaborative work among design and construction teams

Integration of virtual reality within the built environment curriculum

Virtual Reality (VR) technology is still perceived by many as being inaccessible and cost prohibitive with VR applications considered expensive to develop as well as challenging to operate. This paper reflects on current developments in VR technologies and describes an approach adopted for its phased integration into the academic curriculum of built environment students. The process and end results of implementing the integration are discussed and the paper illustrates the challenges of introducing VR, including the acceptance of the technology by academic staff and students, interest from industry, and issues pertaining to model development. It sets out to show that fairly sophisticated VR models can now be created by non-VR specialists using commercially available software and advocates that the implementation of VR will increase alongside industryis adoption of these tools and the emergence of a new generation of students with VR skills. The study shows that current VR technologies, if integrated appropriately within built environment academic programmes, demonstrate clear promise to provide a foundation for more widespread collaborative working environments

CFD supported modelling of double skin facades in hot arid climates

Previous simulations predict the possibility of reducing cooling demands in office buildings in hot arid areas if a selective double skin facade is used. The reductions on cooling loads in rooms range between 19%-40% depending on the glazing thermal and visual performance characteristics of the exterior glazing of the double skin façade. However considerable uncertainty exists about the air flow rates and temperatures experienced within the channels of these facades. In this work a CFD model is used to predict these conditions for the case of an air-conditioned building in a hot arid climate. This case uniquely allows a CFD model to be applied to the facade independent of the simulation of the main building and its plant. Results show appreciable flow rates and temperatures generated mainly by buoyancy flow over the outer facade skin

The performance of double skin facades in office building refurbishment in hot arid areas

The facade's configuration in hot arid areas is predicted to be responsible for up to 40% of the building's cooling loads. The increasing reliance of public buildings in Cairo on air conditioning systems indicates the failing role of the building envelope to perform its function as a moderator leading to an alarming increase in electricity consumption. Office buildings in Cairo consume 5-7% of the total national energy consumption. The need to reduce energy consumption in this sector targets benefits of reductions of electricity bills to building owners as well as reducing C02 emissions from the built environment due to increasing electricity generation. The lack of maintenance funds left the office building facades in a deteriorated state. This deterioration of image led to abandonment of buildings and loss of economic revenue. Double skin facades were investigated as a novel facade refurbishment option, targeting a multi criteria framework for facade refurbishment set in this thesis. To achieve the aim of the thesis, different facade technologies were simulated using a dynamic software (APACHE v.4.3.1) to understand their thermal performance. Quantitative results of simulations were parametrically examined to identify benchmark options for facade refurbishment to reduce building total cooling loads. Simulations results indicated up to 40% reductions in total cooling loads if a double skin facade with an outer reflective surface is used. Information generated from the simulation of single and double skin facade configurations were inducted into qualitative theories predicting human comfort aspects within the workplace. Three qualitative criteria underpinning the psychological comfort of occupants and its impact on productivity are set for balancing energy saving measures through facade refurbishment. These criteria are: the need for a view out, day light availability for non-task performances, and perceived control over the facade in work places.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Association of Researchers in Construction Management

This document may differ from the final, published version of the research and has been made available online in accordance with publisher policies. To read and/or cite from the published version of the research, please visit the publisher's website (a subscription may be required.) Hamza, N and Greenwood,

Experts versus the public : perceptions of siting wind turbines and performance concerns

Experiences of wind turbines (WT) shape public perception and acceptance of the tech- nology, influencing government policy, deployment, and land-use policies of wind turbines. This paper attempts to find changes in public perceptions over the last three decades and differences between experts and the public over different land-use options. A semi-structured questionnaire that integrates a visual survey of 10 images of WT technology in different urban, landscape and seascape settings was presented to both groups. The perceptions of siting, proximity, landscape type, and maturity of urban wind turbines’ technology in renewable energy generation were con- trasted. The results revealed that both the public and experts alike significantly preferred images of WT inclusion in seascape and landscape settings and responded negatively to images of WT as an addition to buildings in urban contexts. Images of wind turbines around transport settings were ranked in the second set of acceptances, after landscape settings, indicating that closer proximity to WT is acceptable, but for a short duration. The analysis also highlighted a preference by the public for aesthetically engaging WT, even if they resulted in lower energy yields, but were less accepted by the experts who based their judgment on technical performance.peer-reviewe

Building Information Modelling: empowering energy conscious design

The increasing awareness of climate change and carbon dioxide emissions from the built environment is resulting in the need to visualize the environmental performance of buildings. One of the recent drivers in the UK has been the tightening of building regulations relating to energy consumption in buildings, mandating all buildings to be performance evaluated by accredited environmental simulation tools to test their carbon dioxide emission against set targets. Currently there is major confusion on all levels from architects to building control officers and contractors on how to engrain energy consciousness principles in the design and construction of buildings. Within this context, ‘Building Information Modelling’ that is linked to ‘Building Performance Modelling’ is increasingly being looked upon as a tool to facilitate the communication between the design team and contractors and to provide a transparent information model on the specification and targeted energy consumption of all new/ refurbished buildings to all parties involved. In this paper, analysis of the benefits and drawbacks of current efforts to combine those two comprehensive databases will be investigated. A sample of main software development companies, architects and contractors, using semi-structured interviews is undertaken to find out how Building Integrated Modelling (BIM) and Building Performance Modelling (BPM) can support the design and construction teams to deliver energy conscious buildings

Double versus single skin in hot arid areas

Double skin facades are defined as two layers of facade separated by an air gap, that varies in its depth creating a solar chimney effect where warm air rises by buoyancy. As a facade technology, its thermal and daylight performance is still under scientific scrutiny. The bulk of research on the performance of this facade configuration is carried out in moderate climates. However, little is understood about the performance of double skin facade configurations in extreme hot arid climates. This investigation adopts an analytical approach using a dynamic simulation software (IESVE), to convert general intuitions on the performance of a double skin facade, in hot arid areas, into the grounds of understanding its performance based on research. It is an opportunity to study this facade configuration before the technology is transferred into construction in hot arid areas. In this paper, a comparative analysis of cooling loads on a single skin base case is compared against three possible changes to the physical properties of the external layer of the double skin facade. A dynamic thermal performance software APACHE-Sim is used (integrated environmental solutions IESVE, version 5.1). Simulation results indicate that a reflective double skin facade can achieve better energy savings than a single skin with reflective glazing

An operational model for teaching low energy architecture

Awareness of the need to integrate sustainability at all levels has recently been gaining momentum in education to meet pedagogical university policy, government and employers’ expectations. Within the School of the Built Environment at Northumbria University, an integrated project base has been adopted for second year students. The project is based on integrating three modules, where on completion the students would be able to adopt a relational thinking process taking energy conservation right into the design phase. A questionnaire was conducted at the end of the academic year on 12 students to assess the pros and cons of the integrated project work. This paper intends to disseminate an operational model for integrating teaching and assessment between three modules dealing with design, assessing environmental performance and visualization, which have traditionally been taught and assessed separately, to achieve a low-energy house

Energy conservation regulations: impacts on design and procurement of low energy buildings

To reduce the substantial contribution of the built environment to energy consumption and carbon dioxide emissions, the new ‘Part L: Conservation of Fuel and Power’ of the Building Regulations for England and Wales came into force in April, 2006. As a result, the design of all new-build and refurbished buildings must comply with ‘Target Carbon Emissions Rates’. Apart from the purely practical implications of compliance, the new Part L has prompted interesting questions concerning procurement and the impact on design and construction teams. The so-called ‘traditional method’ of procurement presupposes that designs are, in theory, completed before contractor involvement. In contrast, Design-and-Build (of which there has been a marked increase) relies upon a certain amount of concurrency in design, procurement and construction. In the light of the new Part L requirements, this presents a risk, particularly in the case of environmentally sensitive buildings, where the necessary design iterations are at odds with the contractor's time and cost incentives. These concerns have prompted the current investigation. Although the challenges relate to buildings as a whole, particular attention was paid to façades, as they represent an especially sensitive element. Data collection was by semi-structured interviews from a sample representing a selection of large construction companies, architectural practices and building performance consultants. The research framework was published in the proceedings of the 2007 Conference of the Association of Researchers in Construction Management where it was selected for discussion in an industry-wide forum, and the current paper reflects this response and develops the topic further