Weigh your House… !!!

Today, the ecological footprint of an architectural design is almost too complex to calculate.

“How much does your house weigh?” The question should be asked about today’s buildings — for environmental reasons, since each additional pound of material requires more energy and resources to manufacture, transport and assemble, not to mention to heat, cool, clean and maintain after construction. Designers and clients alike can be easily misled by sustainability ratings that ignore size or scale and focus on minor aspects of a building’s total environmental effect. How important is the efficiency of a furnace if the house is super-sized? Or if it requires a long car commute? Environmentalists in the ’70s used to joke that it was more efficient to live in an apartment in a dense city with the windows open all winter than to live in a solar house with an hour-long commute — a contention that would depend on the location of the city and the size of the car. The point is to get the scale right.

Architects necessarily focus on the physical scale of buildings and sites, but environmental flows and effects operate at many other scales and along other dimensions, from the biochemical to the global. The late economist and organizational theorist Herbert Simon argued that all complex systems organize themselves into discrete, interrelated and hierarchical sub-systems. The impact of water use and storm runoff in buildings, for example, relates to local watershed capacity, while the environmental cost and value of construction materials are regional and even global concerns involving interconnected manufacturing, transportation, installation and disposal systems. The first task of environmental design, then, is to identify the sub-systems with which a project will interact.

This isn’t an easy task. Complex ecosystems are marvelous in the number and variety of their sub-systems, and in their overlapping, interpenetrating and cooperating scales. Fixed components like plants and trees (or buildings) are penetrated by mobile populations of microbes, insects and animals, and by equally mobile systems of water and air, and any of these can facilitate subtle exchanges of materials and then suddenly transport vast quantities of the same material. This dynamism poses a challenge to traditional architectural thinking, which defines design in formal and spatial terms, as an activity defined by clear, visible boundaries, and which tends to analyze and represent buildings as fixed and durable objects. That said, since at least the mid-20th century designers have experimented with methods for addressing the dynamic aspects of buildings and cities, from flow charts of building activities over time to computational-fluid-dynamic analyses of air temperature to parametric techniques for describing form. These new techniques depict a designed object that differs in many dimensions from the fixed shell of the building, even as the shell remains the organizing focus of architectural design. It is inevitable perhaps — and a singular strength of designers — that successful new techniques are usually expressed visually, as diagrams explaining the environmental qualities of projects.

To succeed, environmental design must make visible the multiple scales and dimensions of the systems within which buildings operate. Architects intuitively understand the different spatial scales of their projects, extending from the building footprint and its legally defined site to the neighborhood, landscape, watershed, city, region, biome, country and continent. But the situation quickly becomes more complex. Some of these scales, such as watershed or biome, are sub-systems of larger ecosystems, and others, such as neighborhood or country, are social and political entities; and the ecological and social-political don’t often correspond. To put it more precisely, human constructions and settlements often begin with the scales and opportunities of natural systems, and then they grow to exceed them. There is no “free” material or energy. Even when our goal is to design “with” natural systems, we are inevitably diverting energy and material from one use to another, which can result in depletion or disruption, on the one hand, or in newly productive human/natural hybrid systems, on the other. Sometimes the result is both: the most spectacular human/natural hybrid system to date is the fossil fuel economy — the global civilization that we have created from the release of the power of ancient photosynthesis stored in petroleum, coal and natural gas, and the epic transformations and disturbances that have followed.

The particular success of fossil fuels is itself a matter of scale, of the density or amount of power that can be concentrated in a small volume. None of the environmental energies — sun, wind, tide, biomass, etc. — approach that density, even when converted to electricity and stored in batteries. The annual electric usage for a nearly typical house (my house) would require about 700 square feet of photovoltaic panels, along with a room full of hardware and batteries. That same energy can be stored in 190 gallons of gasoline — not that you would want to power a house with gasoline — but at every level, the transition from fossil fuel to environmental energies will have this kind of spatial consequence. The general rule of thumb for contemporary photovoltaics is that a fully covered roof of panels can provide the power for a two-story building. The key factors are proportion and the power density of sunlight. Anything taller exceeds the capacity of the panels, and means that additional collection area has to be located elsewhere, whether adjacent to the building or off-site. Of course, most buildings now receive their power from off-site utilities, which quite literally means that the scale of a typical building already extends to a regional scale. (How would Fuller account for that additional weight?) Designers need techniques with which to depict and understand these additional dimensions of their work.

The classic environmental guideline has been for designers to include the spatial scales immediately above and below the building — to start by looking first beyond the building lot and then within to its products and materials. But what about those mobile sub-systems like the atmosphere, power utilities, or the UPS truck, all of which have global reach and effects? This is what we mean by “environmental footprint,” which is another way of asking how much the building weighs. A footprint effectively begins by drawing a spatial boundary around the project and tracking all the flows and exchanges across the boundary: air, water, fuels, electricity, people, UPS delivery, garbage trucks, whatever. A footprint boundary can be drawn around an object, a person, a building, even a country. It isn’t possible to track everything (though it is tempting to try), so a careful analysis involves critical decisions about which flows or sub-systems are relevant. The original ecological footprints sought to quantify and spatialize the “free” contributions of the biosphere (in terms of the area of productive land), but the technique has been adapted to track energy, water, and now the carbon implicated in global climate change. One powerful result of those footprints has been the visualization and proliferation of the concept of “net-zero” exchanges, which happen when the total sum of the flows of a particular element back and forth across the boundary equals zero. With respect to that environmental element, the house could be said to weigh nothing. Fuller would surely approve.

Creating a footprint to track primary energy sources, for example, illustrates the equivalencies and spatial implications of the many kinds of energy used in an ordinary household. The typical electric power (the 190 gallons of fuel, for my house) is about 50 times the amount of food energy consumed by a family of three through the year; this means that next to the 190-gallon gasoline tank (which weighs about 1,500 pounds) would sit a 150-pound pile of grain (the food with the greatest energy density), though the fuel to heat the house would weigh an additional 3,500 pounds. What the footprint shows is that the answer to Fuller’s question would have to include these other weighty elements, and that even the lightest building shell requires a whole other pile of materials and resources. Preindustrial households would stockpile supplies right on the premises, requiring specialized storage of different kinds; our contemporary arrangements are based on large networks of supply, which provide just-in-time flows of foods and fuels and which minimize on-site storage. Like our mobile phone and wireless networks, a hugely extensive (and weighty) infrastructure is deployed to make the final activity appear weightless. By including such connections, a carefully constructed project footprint can dramatically alter the design challenge, simply by making flows of different scales visible and available to the design process.

But environmental footprints remain fundamentally spatial because they are defined by boundaries (although my examples have already blurred the distinction by including weights or amounts of resources over time). The next step is to factor in the dimension of time. Temporal scales are a critical aspect of building design. They are partly captured by spatializing them — e.g., so many pounds or gallons per year, as in the examples above; but examining the rate-of-change or “velocity” of building elements would reveal a different dimension of construction. In a real sense, every element of a building is in motion, stopped for some discrete period to become part of the building, but ultimately moved on.

Now, a modified question might be: “How much does your building weigh and how much does it change every year?”

Environmentally-minded designers generally agree that making such temporal distinctions explicit can improve the resource efficiency of buildings, allowing for easier, less disruptive adaptations and more effective recycling. This approach is already being translated into other construction types, especially residential, and into new construction practices such as the tagging of individual elements to facilitate disassembly and recycling. But layers are separable only up to a point. In any natural ecosystem, interpenetration and exchange between layers are critical to the operation of the system, and so it is with buildings. Some elements simply have to cross the boundaries between different layers because some systems are themselves made up of items of different velocities, and the joints between them present important design challenges.

The simplest example is the electric supply system, which consists of a longer-duration wiring network, typically concealed within other long-duration elements, and the more frequently changed cords and plugs that connect equipment and appliances to the power network. The boundary or connection between the two is the electric outlet, a seemingly mundane device that is regulated by electric safety standards, on the one hand, and that can be highly varied in shape, appearance and color, on the other. Whole aisles in building supply stores are filled with “decorative” finish choices for outlets and outlet covers, which function to manage the emergence of the concealed power system into occupied, “decorated” space. It’s very like the now-familiar hardware-software distinction: the longer-lived hardware hosts the more quickly changing software with which we interact — and that interaction itself is increasingly part of everyday building elements as smart systems penetrate into everything. The point is not just that many different layer-crossing situations already exist in buildings (and these become visible once we understand their temporal dimensions), but also that that many more are likely to emerge as building systems and construction evolve (for example, as we develop local or shared utility arrangements to compensate for the lower density, and reduced power, of new energy sources).

When we make visible the spatial and temporal dimensions of design projects, the object of environmental design shifts and changes. The environmental movement has argued since at least the 1970s that the ultimate scale for design is the biosphere; but that overstates the task presented to designers. Architectural design is always situated within discrete natural sub-systems, even as these systems are hybridized with human systems and penetrated by other more mobile or global systems. Environmental design involves a number of neglected dimensions, but the contemporary adjustment to his question might be to expand it from the house to the household, which would comprise all the people and things that belong to a particular building: family, employees, equipment, etc. The “weight” of the household would include those 1,500 pounds of fuel and the 150 pounds of grain; plus we’d have to add the 1,000,000 pounds of water typically used every year, as well as the cars, appliances, furniture, clothes and stuff that fill houses, garages, self-storage cubicles, even the offices to which we commute.

Matter referenced:

William W. Braham. Sep. 2009. How Much Does Your Household Weigh? Places Journal.

By: Dr. Bhawana Asnani.

Happy to see Reviews, Additions, Suggestions and Comments, further.