Embedding sustainability in the design of water supply and drainage systems for buildings

In addressing sustainability issues for the built environment, focus is often directed towards minimising energy consumption and material use. Often forgotten however, is the potential for the integration of sustainable solutions when designing water and waste management systems for buildings. The fundamental functions of such systems are clearly recognised, but traditional design principles often constrain opportunities for performance enhancement and for water and pipework economies. To an extent, this is unsurprising, given the basic premise that steady-state analysis of flows underpins many of the codes and guidelines used worldwide. However, advances in simulation methods mean that system performance resulting from the use of new techniques and from the integration of innovative and more sustainable design approaches can now be fully assessed. This paper provides an overview of the water supply and drainage systems for buildings whose performance has been assessed through the development, at Heriot–Watt University, of a suite of numerical simulation models. These models accurately predict, using appropriate forms of the St. Venant equations, the pressure and flow regime within such systems by applying the Method of Characteristics finite difference technique. The paper provides three different examples of application, where the focus of each is on embedding sustainability in design.