Description

Basically, the construction and operation of buildings causes environmental damage, for there is no ecologically correct procedure for the construction and maintenance of buildings; there are only more or less environmentally damaging processes and materials.

Energy is required at every stage of completion, operation and demolition; transportation causes damage to the environment by generating wastes that are toxic both to humans and to nature in general.

Almost half the energy consumed in Europe is used to run buildings; at least a further 25% is expended on transportation. Per capita energy consumption is almost three times higher in North America than it is in the other western industrialised nations. Scientists estimate that the world would have to be four times the size it is in order for all countries to live as the industrialised nations do.

Humanity’s living space is endangered by three critical developments that reciprocally influence each other:

• Population explosion

• Noxious emissions

• Depletion of natural resources

The core problem of population explosion is that it menaces future generations in a way that is not foreseeable, while the destruction of living space through noxious emissions is happening increasingly quickly and at the same time, natural resources are being used up.

Ruthless intensive farming methods and destructive exploitation of raw materials as well as a world-wide decrease in agricultural acreage are causing a growing reduction of natural living space.

In the western industrialised nations’ call for global agreements on the protection of the earth’s large areas of tropical rainforest, the problem of the extreme poverty of these regions has not been responsibly addressed. The peoples of the so-called Third World will insist on their right to satisfy their existential needs – if necessary even by despoiling nature – as long as the industrial nations continue to cultivate their own wasteful way of life.

At the same time, in the course of globalisation and the rapid development of a communications society, larger and larger complexes of service and administrative buildings are being erected, not only in the industrialised nations, but also in the industrial conurbations of other areas. In the large East Asian cities above all, millions of square metres of office space have been and are being built with antiquated building technology standards, which further accelerates the world-wide consumption of energy and resources.

Against this background, a paradigm change is indispensable when considering the lifecycle of office buildings. This will mean that the volume of planning is vastly increased, and debates over architectonic conception can no longer be conducted without taking account of sustainability criteria. If the concept of ‘sustainable development’ is to be effectively implanted in our economic system, it must not be limited to ecological aspects; it is rather a question of integrating economic, social and cultural values in planning concepts in such a way that a holistic strategy for sustainable building concepts is developed. It is not a matter of radical solutions, but rather of a holistic approach and an appropriate balance within the triangle of goals shown below.

We know that many of the problems facing our environment are caused by society’s ever more efficiently designed specialisation. Individual aspects of production, processes and materials are not only being optimised to apparent perfection, but also, they have a negative effect on the natural habitat as a whole, as the optimisation methods do not take sufficient account of the natural balance of the whole system. This criticism does not represent a call for retreating from highly technological systems – it is instead a plea for embedding state-of-the-art technology in the triangle of goals of socio-cultural context, ecology and economy in a balanced way.Thus an office building designed to be sustainable offers more than just a climatic envelope.

The bond between inside and outside has increased in importance for our living habits, as new materials and technologies have made it easier and less of an effort to fulfil those building functions that provide protection from nature. In so doing, the building is more tightly integrated into the environment – the transitions in the envelope are more graduated – light can be directed, filtered, buffered, subdued, fractured and reflected. Energy currents are more regulable. The psychological gain that a transparent envelope offers, the seeing and experiencing of day and night, wind and weather, summer and winter, became an important component of open and exciting architecture in the twentieth century. Thus it has become one of the responsibilities of our time not only to channel natural daylight from an energetic aspect, but also to integrate its influences on the physical constitution and on the psyche into architectonic concepts.

From this perspective, the goal has to be to avoid optimising energetic building concepts one-sidedly and exclusively for their own sake at the cost of spatial qualities and quality of life. Instead, innovative and high-quality occupancy concepts for daily office tasks that open new avenues for energy conservation must be developed.

In the best case, architectonic living spaces are holistically developed, through the definition not only of walls, ceilings and floors, but also of light, temperature, air exchange, odour and acoustics.

In this connection, the structural assembly and also the construction of a building are to be seen as essential components of a sustainable architecture. In the current debate over optimum energy concepts for buildings, the conditioning of the interior climate through heating, cooling, ventilation, lighting and the handling of other heating loads generated by appliances is often discussed as if it were a separate issue. Questions about the extraction of raw materials, processing to transform them into construction materials and semi-manufactured products, transportation and final assembly at the building site, questions about building maintenance and lifespan, repair and alteration/renovation costs such as demolition and recycling are treated as peripheral, if at all. Yet it is nonetheless a matter of methodically integrating this principle within the development of a site, for there is still no overarching system of evaluation criteria for construction material that would allow ecological comparison of different construction systems. New methodical approaches attempt to distinguish biotic materials from abiotic materials in the flow of materials and to measure water, soil, air and energy in units per square metre of building component. It is a matter of minimising the corresponding material intensity, which is also described as the ecological backpack. The hierarchy in the selection of materials and construction is as follows:

• Reduce

• Re-use

• Recycle

This means:

• A building that is constructed with low-cost materials is usually energetically optimised with regard to fabrication as well.

• A long-lived, flexibly designed building characterised by easy adaptation to changing occupancy demands is a worthy goal from an energetic viewpoint as well.

• A clear structural fabric of building elements and subsystems is one that is built in such a way that it can be dismantled. The recycling of individual components is facilitated by adding interstitial treatments appropriate to the material and simplicity of detailing.

Values such as ‘clarity of structure’ and ‘suitability of means’ take on new meaning when viewed from the perspective of sustainability: energetic and ecological questions pose new challenges to architecture, which will have a significant influence on the design of the built environment.

On a more abstract level, a series of clearly defined directives for the goal of sustainable planning can easily be given:

• Work-related physiological and psychological influences and concerns must be taken into account for the design of the building structure.

• Specific site factors (topography, vegetation, infrastructure and cultural environment) have to be taken into account in the integration of the building complex in the local context.

• The use – passive wherever possible – of climatic conditions of reference (solar radiation, wind, daily and seasonal temperature variation, geothermal conditions, temperatures of bodies of water, humidity, supply of daylight) for natural building conditioning.

• Reduction of material flows during the total lifecycle of a building.

• Reduction of energy flows that have to be artificially supported throughout the lifecycle of a building.

• Integration of renewable raw materials in the building structure.

• Development of reusable building materials and demountable structures.

In the practical decision process, the evaluation of such directives may, however, entail conflict as to the goals, which can lead to very different building concepts. For example, those forms of organisation that permit construction itself to be dispensed with, or those with multi-occupancy workplaces appear to comply with the requirement to consistently reduce the flow of materials and energy. However, as buildings must be evaluated not only using ecological criteria, but also from a socio-cultural perspective and taking into account their total economic benefit, the attempt to render office buildings superfluous by having work done on the computer at home, although ecologically desirable, would be unrealistic for society as a whole. In future, although fewer single-occupant workplaces will be set up, the office building will nonetheless play a much more important role in the establishment of social contacts and personal communication among employees – the reduction in the number of workplaces that are actually set up will be compensated for by a greater supply of space for social encounters.

Just as modern communication technologies have not radically reduced paper consumption, they will not lower the total area consumed by buildings in the near future either.

The extent to which existing stocks of buildings can be maintained and refurbished to meet the new requirement profile of office buildings in keeping with the times, although of great interest from an ecological perspective, must nonetheless be tested case by case, for example, to verify whether modern technology can be retrofitted, or whether overly rigid floor plans stand in the way of a communicative building concept optimally oriented to the corporate image.

The globalisation of the economy and the transfer of knowledge across world-wide networks will undoubtedly lead to increased construction of office buildings not only in America and in Europe, but above all in the Asian countries. The development of newer, ecologically optimised building forms and technologies is therefore gaining in importance. Until now, linear thinking and planning have characterised the development of buildings and building technology. Individual products and systems were – and to some extent still are – geared to individual aspects of building, although this is clearly recognisable as being the wrong way to the future.

It is true that a sophisticated understanding of energetic processes and the technologies that have a regulative effect on them provides the basis for planning decisions. However, merely knowing the catalogue of building construction and individual technical measures for regulating an interior climate, for example, such as storage technologies, heat exchangers, collectors, thermo-electric effects, waste air façades, controlled ventilation systems etc. leads to purely additive thinking and acting.

In the foreground is therefore the principle of not extracting such individual aspects from the whole context and then observing them in isolation, but rather of integrating them in the total system of the building, for it is precisely in overcoming conflicts about goals that the real problem of building design lies. This will be possible only through an integral planning process in which occupants, architects and engineers together work out an optimal building concept through comprehensive collaboration of the different disciplines. Each task requires a unique definition of its original goals.

“Building with mass” can be as important as “building without weight;” the appropriate solution results from the determination of the terms of reference, not necessarily from the possibilities that products on the market offer us, for example. With regard to the cost of climate technology apparatus, the requirement that it be low-tech might be right, while at the same time the facility management will be technically augmented and the construction costs will rise due to the sophistication of detail solutions. Office building planning can save on work-places and thereby construction and running costs and use the money saved to equip buildings with information and communications technology that meet the highest standard – even if the total building investment (including its equipment) remains the same, the ecological balance sheet is improved. Comprehensive planning that clients in particular have a share in provides the basis for cutting material costs and particularly running costs.

Computer-generated climate simulations of the daily and seasonal temperature differences in the building, daylight simulations under an artificial sky, experiments with air flow in wind tunnels or in the building itself in order to optimise control engineering elements represent high initial costs for engineering, but in addition to radically reducing running costs, they also offer substantial potential savings in investment costs in future.

In the following, four comprehensive integral planning approaches will be introduced as examples. The methodical approach is based on a number of strategies:

• Reactivation of old building stock;

• Activation of synergetic effects through new work forms and forms of living;

• Less reliance on apparatus for air-conditioning through design and construction measures;

• Sustainable building component optimisation through the disentanglement of functions and the increased implementation of ecologically safe materials.

Conversion of a production facility to an open-plan office

The architects Thomas Herzog and José-Luis Moro developed a design studio for Siemens-Design & Messe GmbH in Munich from a scrapped industrial facility which was dark in the middle and only equipped with the simplest hot-air heating, single glazing with old cast panes and an uninsulated steel skeleton. A well-rounded working environment with optimal daylight conditions, an interior climate appropriate to sedentary activity, and functionally efficient acoustics was to be developed on a low budget for circa 60 designers. The architects designed a second skin in the form of an internal cocoon of a biaxial spanning membrane, completely detached from the old existing façade.

In the upper regions, the double-layered, translucent membrane provides the necessary thermal insulation thanks to the static air space enclosed between the two layers of foil, as well as providing for sufficient natural light. It follows the profile of the hall to a large extent and is point-suspended by means of cables from the old steel structure. This skin begins at a height of 2.5 metres. Underneath, a wood and glass façade was set against the old glazing from inside, so as to ensure the view, the natural window ventilation and damage protection for the delicate membrane. The new floor, raised by 40 centimetres, creates a suitable hollow space for the thermal insulation as well as for supplying the workplaces with electric cables and ventilation ducts.

Only in the places where people can see directly outside were new, openable windows in­stalled. A continuous glazed band as an opening in the ridge of the roof brings daylight from the roof level into the interior, which changes the entire aspect of the space. Between the building envelope – which was left in its old state – and the membrane, is a closed airspace that has the effect of a thermal buffer. In summer it can be ventilated by means of the openings in the façade and in the roof, and in winter in extremely cold weather, it can be warmed by means of the already existing ceiling air heater in the hall. When humidity is high, this buffer space is ventilated mechanically.

With its sound-absorbing effect, the membrane provides a comfortable acoustic environment. In order to meet fire safety requirements, a fully recyclable and environmentally harmless fluoroplastic that is flame retardant and does not melt when it catches fire was selected for the inner skin.

Replacement of a mechanical ventilation facility through the structural integration of a thermal tunnel and a waste air chimney

At first a mechanical ventilation facility was proposed for the round entrance hall of the LVA in Augsburg, because of its great depth of over 40 metres. In order to reduce investment and running costs significantly, a natural climate concept based on the principle of a waste air chimney was suggested for this large spatial volume. This waste air chimney was arranged as a cost-efficient static air extraction device between the elevators.

Air is carried through a thermal tunnel into the basement of the building, where it comes out – without causing any draughts – through wall baffles that distribute the influx of air over large areas. There is a height difference of 25 metres between the waste air exit via the roof and the source air duct.

In summer, the thermal tunnel pre-cools the air; in winter, it is pre-heated. Through natural thermal and aerodynamic effects, the air in the hall is drawn off near the roof via the waste air chimney and exits above the attic. This natural ventilation can be mechanically supported and/or throttled by means of flaps in inclement weather conditions. In the smoke experiment illustrated here, this control mechanism was switched on and tested before being put into operation. This construction principle ensures a dual air change in the hall year-round – for this, the volume of air coming in was set at 25,000 m³/h with a waste air volume current of 2 x 12,500 m³/h.

In order to further improve the climate in the hall, an extensive planting was planned, which in addition to having a cooling effect through air evaporation also bonds dust and creates more comfortable acoustics in the waiting areas. A central skylight with efficient solar protection glass that prevents too much solar radiation in summer provides for natural lighting of the hall throughout the day and thus reduces the length of time artificial lights are switched on to a minimum.

Optimisation of daylight quality for workplaces through multifunctional solar protection systems

For the new building commissioned by Firma Gartner, a construction enterprise, Kurt Ackermann developed a sophisticated daylighting concept that enables measured and individually regulable illumination of the workplaces with a high degree of visual comfort. The two-storey office complex houses 120 comfortable, functionally equivalent computer workplaces. The skylight running the whole length of the building and large perforations in the ceiling of the false ceiling increase the amount of natural light at the floor level. Brise-soleils of tiltable aluminium louvres control the amount of radiation and light coming in, the same way as a north-facing Sheddach roof form does, so that direct sunlight is screened.

The solar protection on the north and south façades consists on both floors of frameless tiltable glass louvres, 10 mm thick and 300 mm wide, whose axes are arranged parallel to the façade. If the louvres are adjusted correctly, stripe-free shading of the window surfaces is ensured in direct sunlight. Unlike conventional systems with non-transparent louvres, this solar protection device with semi-transparent louvres allow occupants to see out, even when the louvres are shut due to the angle of the sun. If the façade in question does not get any solar radiation, the louvres are swivelled to a horizontal position. They can be adjusted in such a way that the louvres serve not only as reflectors for the diffuse daylight, but also for steeply angled solar radiation – they reflect the light onto the ceilings to illuminate the backs of the rooms. In this way, computer workplaces near the windows receive only the necessary daylight, while there is more light at the back of the room so that even there, workplaces are supplied with natural light. In order to regulate the intensity of the illumination and to limit glare, blinds of fibre­glass textile have been fixed to the interior of the façade to protect against glare.

Herzog + Partner developed a similar solar protection and light diverting principle for an admin­istrative building in Wiesbaden. However, the reflecting material in this case is not coated glass, but highly reflective sheet aluminium. The inclination and design appropriate for reflecting are specifically adapted to direct or indirect light. By means of an electric motor, the shovel-like structure on the south side of the building can be folded back so that direct solar radiation is directed deep into the rooms by an aluminium light reflector beneath the maintenance balcony, without the workplaces at the windows being subjected to glare. In spite of effective sunscreens, sufficient daylight can be brought into the rooms so that supplementary artificial lighting can be dispensed with.

---

Originally published in: Rainer Hascher, Simone Jeska, Birgit Klauck, Office Buildings: A Design Manual, Birkhäuser, 2002.