Niklaus Kohler

The relevance of Green Building Challenge: an observer's perspective

The objectives and achievements of the international Green Building Challenge project are analysed. GBC is situated within the context of other international environmental methods. The differences between assessment tools, design tools, environmental management and audit tools and the large data problems entailed by these are discussed. Possible development scenarios for extending GBC into Life Cycle Assessment methodology, into other life cycle phases (maintenance and refurbishment) and adapting GBC for use with the existing building stocks are proposed. The notion of ‘green’ buildings is replaced by a larger concept of sustainable development. New aggregation principles and scaleable design methods are proposed. Finally, the question of how relevant the proposed targets of GBC are in relation to the longterm sustainable development of buildings, building stock and urban environments is addressed. Cet article analyse les objectifs et les resultats du projet international Green Building Challenge (GBC). L...

Resilience in the built environment

A new arena? Resilience, as a design principle, was an implicit part of traditional construction knowledge before the 19th century. The oversizing of components and spaces, redundancy, and reparability were forms of tacit construction knowledge (Schön, 1983) that enhanced the resilience of buildings. In contrast, the modern engineering concept of resilience originated from material technology in the 19th century. This modern approach replaced the traditional dimensioning rules by formal rules of calculation (based on experiment) in order to optimize both (structural) safety and the (reduced) consumption of materials. Resilience as a long-term design principle and resilience as a functional, disciplinary model (i.e. the application of resilience in structural engineering) are not identical; and in some situations can be contradictory. The former approach provides for unknown uses and adaption, the latter focuses on providing a specific, tailored solution to one particular brief and set of functions.

Research on the building stock and its applications

Traditionally, architects and engineers were interested in designing new buildings, town planners and political authorities in planning the growth of settlements and cities. Their ideas are still strongly conditioned by the post-1945 boom, which has doubled the building and infrastructure stocks of most European countries. The centre of interest has been in expanding, open systems. But over the last few years, clear new trends have appeared: interest is shifting gradually from managing growth to managing saturated steady-state situations. Indeed, there is also recognition on the need to manage the decline (or shrinkage) of the built environment. In the building context, a stock-centred view replaces the fascination for continuous growth in input flows, and the ignorance of output flows and side-effects. Kenneth Boulding anticipated this shift from ‘cowboy economics to spaceman economics’ more than 40 years ago:

Deconstruction, demolition and destruction

There is a large general agreement on what constitutes ‘demolition’: it is the complete elimination of all parts of a building at a specific location and time – typically it is the end of life for the building. Unlike the initial phases of design and construction (which fill most of the shelves of architectural libraries), the end-of-life phase of buildings has received little scientific attention so far, although its quantitative and qualitative significance is considerable. However, partial demolition actually begins during the service life of buildings as maintenance and adaptation include the replacement of building parts, resulting in a considerable waste flow. Over a very long life-span this has been shown to exceed the waste flow from simple demolition. From the perspective of waste prevention, the downstream flows of the building stock (i.e. ‘construction waste’), will be an issue of growing importance in both construction and property management.

The ideal of resilient systems and questions of continuity

The importance of resilience is contextualized within the sustainable long-term management of the built environment. The built environment is considered as a set of different capitals (natural, physical, economic, social and cultural) with limited possibilities for substitution between the capitals. Resilience is related to other concepts used in the search for a sustainable development of the built environment: continuity, stability and equilibrium, duration and durability, robustness and vulnerability, fast- and slow-moving risks. Cultural capital (in its material and intangible forms) as well as natural capital are significant due to long foresight considerations, high uncertainty and limitations on substitutions. Different time and scale categories and the conservation of different capitals need different anticipation and resilience strategies. It is argued that natural and cultural capitals can be transmitted if they are conservatively used and if adaptation occurs slowly. Specific strategies are needed for the ‘non-recoverability’ of cultural capital.

Long-term design, management and finance for the built environment

Introduction Modern interest in life cycle costs of buildings dates back to the 1950s. However, the idea of the long-term behaviour of buildings goes back to Vitruvius’ requirement of ‘firmitas’ and has been an essential part of Western building culture up to the pre-modern tradition of solidity, based on the rules of the art of craftsmanship. A significant part of the European building stock still illustrates daily how qualities of use, form, construction, durability, and solidity can very successfully coexist. In the last decade a considerable amount of research and development has again been dedicated to predict and improve the long-term behaviour of buildings and infrastructures, but there are still difficulties to realize constructions that are comparable in durability to standard buildings of the 19th century. How building costs relate to long-term behaviour of buildings is a multifold question that specifically arises in modern economic culture where previously it was accepted as a common ‘good’. Modern business practices based on payback periods, financial discounting, etc. have eroded one’s confidence and ability to take a whole-life view, but this book provides professionals and clients with a useful set of alternatives.

Life Cycle Models of Buildings — A New Approach

The idea of life cycle cost was developed a quarter of a century ago. A wide dissemination of the term was given through a report for the US Secretary of Defense “Life Cycle Cost in Equipment Procuration” [LMI65]. This report was followed by a series of guide lines in the defense field and later on in other government activities. The basic definition of life cycle costs is: “The sum of all costs incurred during the lifetime of an item, i.e. the total of procurement and ownership costs.” [DHI89].

Sustainability of New Work Practises and Building Concepts

New forms of communication and co-operation do not have the same environmental impact pattern as current forms of work. Environmental impacts are produced by work technologies (mainly communication technologies), buildings (construction, maintenance, operation and destruction) and transport (induced by work relations and housing). The thesis that new information technologies reduce transport and building energy consumption has not been verified in practice until now. The contribution discusses the interrelation between different impacts, gives quantitative data of environmental impact based on the combination of existing life cycle analysis and tries to estimate possible future developments. The question of the necessity of new buildings and the possible development of virtual buildings is discussed in relation with sustainable development.

From the design of green buildings to resilience management of building stocks

ABSTRACT The green and the subsequent sustainable building movements have been framed by changing societal contexts. Their main focus has been on the design of new buildings. However, these movements have neglected the life span of existing buildings and the long-term management of building stocks. The reasons why are considered: the changing interpretations of sustainability, the evolution of different forms of tacit knowledge, lack of a metabolic framework covering the built environment and lack of a consistent multi-scale building information modelling (BIM). The transition toward a ‘risk society’, with an increasing diversity and frequency of threats, challenges the current optimistic definition of sustainability. Resilience addresses fast- and slow-moving threats that can lead to unknown consequences and new risks. Alternative planning approaches (e.g. scenario planning, adaptive change and resilience heuristics) are discussed. The differences between anticipation- and resilience-based strategies are considered. Possible heuristics can be found in social–ecological systems, in resilience engineering and in the historic evolution of the built environment. Resilient solutions generally lead to a higher level of complexity and carry additional environmental costs. In the creation of resilience capacity, new knowledge will be co-produced through transdisciplinary research, scenario planning and design experiments under conditions of uncertainty.

Energieeffiziente Stadt – vom Konzept zur Umsetzung

Der Beitrag stellt den Ablauf und die Resultate des Wettbewerbs „Energieeffiziente Stadt“ vor. Stadten und Kommunen kommt im Hinblick auf die Umsetzung der Klimaziele der Bundesregierung eine besonders wichtige Rolle zu. Die Form des Wettbewerbs, mit expliziten Vorgaben zu den Zielen und zur Zusammensetzung der Projektkonsortien, erlaubte es, die Komponenten Technologien (Bestand, Netzwerke), Nutzerbeteiligung und neue Dienstleistungen miteinander zu verknupfen. Die Antwort auf die Ausschreibung war sehr positiv. In der ersten Runde haben sich 72 Stadte und Kommunen beteiligt. 15 Projekte wurden zur weiteren Bearbeitung ausgewahlt und wahrend eines Jahres gefordert. Zum Schluss wurden 5 Projekte ausgewahlt, die wahrend mehrerer Jahre gefordert werden und den Nachweis erbringen sollen, dass die Klimaziele bis 2020 auf kommunaler Ebene erreicht werden konnen. Der Aufwand hat sich fur alle Projektteams gelohnt, weil in allen Fallen neue Probleme aufgetaucht sind, sich neue Diskussionen und Kooperationen zwischen den verschiedenen Akteuren der Stadt ergeben haben und neue Ideen sehr schnell verbreitet wurden.