The appliance trap seal remains the primary defence against cross-contamination from the foul air present within the building drainage system. As an identified vector in the spread of severe acute respiratory syndrome (SARS) in Hong Kong in 2003, trap seal failure has been confirmed as a significant, and potentially fatal, risk to public health. Prevention of trap seal failure depends upon both good design, to limit the air pressure transients propagated within the system, and good maintenance. However, current maintenance regimes rely solely on visual inspections which is time consuming and often impractical to implement in large complex buildings. This thesis documents the development of a novel approach to system maintenance whereby the threat of cross-contamination of disease is minimised by the remote monitoring of trap seal status. This was approached through the application and development of the reflected wave technique which is fundamentally based upon the characteristic reflection coefficients of system boundary conditions. An extensive programme of laboratory experiments and field trials were carried out to collect transient pressure data which, together with results from an existing mathematical model (AIRNET), developed by the Drainage Research Group at Heriot- Watt University, have been used to validate the proposed technique and to formulate a practical methodology which may be applied to any building drainage system. Automatic system diagnosis, which would in the future allow the proposed technique to be integrated as an automated system test, was provided by the development of the trap condition evaluator (TRACER) program by this author. Incorporating a time series change detection algorithm, the TRACER program accurately detects and locates a depleted trap seal by automatically identifying the return time of the trap’s reflection. The reflected wave technique has been demonstrated as a successful approach to depleted trap identification provided that the wave propagation speed is known and the dampening influence of the junction effect (which can delay the observed reflection return time) are taken into account. The reflected wave technique offers a remote and non-invasive approach to maintaining the building drainage system and provides, for the first time, a diagnostic tool to help prevent cross-contamination.

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Portland cements (PC) and blended PCs are the most commonly used binders in stabilisation/solidification (S/S) applications. However, such systems have found limited suitability with organic contaminants. Moreover, the high alkalinity associated with PC militates against the soil microbes and hence, hinders the natural attenuation of the organics. Furthermore, the production of PC is not only an extremely resource and energy intensive process but also has significant negative environmental impacts. Thus, with the aim of tackling the above issues, this research has been focused on firstly developing and applying a low-pH binder system for facilitating microbial activity in parallel to the S/S of heavy metals, and additionally on investigating the application of less environmentally damaging cement in S/S. These were addressed employing two novel binders; viz. low pH magnesia phosphate cements (MPCs) and reactive magnesia (MgO) cements respectively. This study was successful in formulating MPC mixes which not only developed low-pH ranges favourable to soil microbes but were also more effective in immobilising heavy metals than PC-based binders in an individual contamination scenario. Furthermore, the heavy metal stabilisation performance of the MPC mixes suffered negligible impact in the presence of organic contaminant.

The need for sustainability (or sustainable development) is widely recognised, and the case for it rarely disputed. There is a particular need for action within the construction industry because of the nature and scale of its activities. Commentaries and statistics on the impacts of the industry abound. Nevertheless there continues to be confusion about the application of sustainable development to construction and the built environment. Using an inductive approach, which follows the <i>roadmap </i>set out by Eisenhardt (1989) for building theories from case studies, four UK educational buildings (the Education Resource Centre at the Eden Project, the Centre for Mathematical Sciences at the University of Cambridge, the Oxstalls Campus at the University of Gloucestershire and the Great Notley Discovery Centre) have been investigated as case studies to address three research questions: What is sustainability in relation to the built environment? Why is it taken into account? and How is it taken into account? Hypotheses have been shaped from analyses of the case studies and evaluated in relation to the literature. It is proposed that for sustainability to be successfully taken into account in a building project there must be a client-driven agenda, an appropriate culture, clear definitions, a means of measurement and the use of tools. It is suggested that this can be undertaken within any contractual form. However, definitions of sustainability in relation to building projects need to be broadened beyond those aspects currently given prominence in the literature.