If the goal is to limit the overcrowding of cars on the street, is it a better solution to dilute density in order to spread people out or to foster the ability for more people to carry out more of their day via alternative transit? Is the best way to avoid excessive signage and light pollution to forcibly segregate all commercial program or might it be easier to simply regulate sizes for signage and candlepower for lighting? In an effort to limit the amount of cooking odors disturbing nearby residences, would it make more sense to remove proximity of all retail business or to set standards for the design and location of cooking exhaust?
Questions like these draw into focus the difference between two mindsets for planning and design, prescriptively restrictive vs. performative. The deeper question is whether it makes more sense to guide design and development by prescribing solutions with an (educated) guess as to how they may perform over time or by simply setting standards for testing how things should actually perform? While the former has proven to be easier for governing bodies in many cases, the latter can be built on what we actually have rather than an idea of what could occur.
For a while now, our built environment has suffered from this dilemma at every scale. From town planning and traffic engineering to the construction of our buildings, our policies have been built on the premise of equations and analysis that may lead to a given outcome rather than simply testing results. Our building codes provide a perfect example.
As noted by the New Buildings Institute, traditional building codes are built on the prescription of physical building characteristics that are meant to lead to certain levels of performance. An example would be a minimum insulating R-Value for an exterior wall assembly. Enforcement takes the form of planning reviews to ratify that intended construction methods meet code requirements along with some potential visual inspections or testing by third parties prior to building completion. After that, most current methods of code enforcement end at the time of building completion and the conveyance of a Certificate of Occupancy. But what is to say that a building will actually perform to the prescribed levels of attributes such as energy use or acoustic separation?
Even rating systems like United States Green Building Council’s LEED that target high performing buildings have historically suffered from the same reality and have come under fire recently for lacking a continuous measure for whether or not built projects meet benchmarks outlined by the design guidelines. LEED has faced inquiries as to whether or not their certified projects actually achieve their forecasted energy reductions upon occupancy and maintain those levels over the life of the building. While there are numerous merits to the LEED system, ensuring that buildings meet the standards that they are certified for has to be a priority not only for the strength of the rating system, but to make sure that we are actually making progress in making our building stock more sustainable.
One option open to us is represented in a shift in thinking to the possibility of “Outcome-Based” codes. Contrary to traditional code structures, an outcome-based policy would end up mandating performance in order to be rendered legally occupiable and maintain that approval over time.
In some ways, the evolution of LEED is pointing in the same direction. The USGBC is ushering in the development of their new Dynamic Plaque that represents data of building resource use over the life of the building. In theory, a building that fell below a threshold of minimum performance could lose their certification level if appropriate changes were not implemented. This would not only allow for building owners to ensure that their LEED energy goals are being met, but also provide ways to easily weigh the benefits of future upgrades as industry technologies advance for different building systems.
Some American municipalities like Seattle, Washington are already looking into ways to transition into an outcome-based model for their building energy policy. For the first time, the 2015 version of the International Green Construction Code also includes an option to use an outcome-based method of complying with local energy codes using as ASHRAE 189.1.
Community activist Jane Jacobs had similar suggestions for how to reassess the archaic zoning models that washed across the majority of suburbia in the middle of the 20th century. As part of their attempt to deviate from the downsides of urban living, suburban models were build on codes that forced a separation of uses or a series of adjacent programmatic monocultures rather than the smaller scale of mixed use that most historical American towns were built on. In essence, these separations were put in place with the thought that moving different use groups apart would prevent any of the potentially negative aspects that direct adjacency could result in such as noise or odors.
In her final book, Dark Age Ahead (reviewed here), Jacobs offers that instead of trying to pre-emptively guess at ways to limit unfavorable results of adjacencies, why not simply build codes that are based on performance? Jacobs suggests:
“Zoning rules and tools neglect performances that outrage people. What are actually needed are prohibitions of destructive performances. To attend hearings on zoning and planning conflicts is to learn that feared changes are not actually about land uses, densities and ground coverage but rather about dreaded side effects. ”
She goes on to explain that:
“A chief advantage of performance codes, especially those updated in light of changing technologies, will be the incentive they offer to solve practical problems that traditional zoning tried to “solve” merely by banishing offenders to poor or politically disregarded parts of town.”
The unintended outcomes (or casualties) of this process are suburban realities like commercial office parks or retail strip malls that leave us with a new respect for the pleasant nature of older town centers that manage to combine all of these things at a walkable scale. Yet we are without a reason as to why that model, or aspects of it, is not achievable to us now.
Perhaps part of the problem is that we still struggle at knowing exactly what it is we want. Maybe only after we came to know the series of repercussions that grew from the suburban experiment have we gotten enough information and experience to allow our goals to of living and working to evolve into something else. In either case, we should target the improvements we want to make and allow our code structure to evolve in kind, allowing for a series of checks and balances that those goals are actually met.
When this interfaces with the idea of sustainability, the opportunities for progress are clear. New buildings that claim to step to a higher level of environmental stewardship could be tested upon completion rather than by design approval. Sweeping strokes across program types could have more success in bring large numbers of buildings up to higher standards with greater reliability.