As parts of the Northeast leave behind days waiting for power and water, Hurricane Sandy’s late October run prompts the question of what we can do to make our urban areas more resilient to minimize the time that we need to keep residents without the bare essentials. There have been a number of articles (here and here) recently written about the comparison between “resiliency” and “sustainability” in an attempt to make a case for which we should ingrain into our cities. Facing the two terms against one another struck me as odd because though we can strive to satisfy one and not the other, there is a great deal of overlap between the two. Sustainable design and construction is often proposed on the merits of environmental stewardship, a healthier indoor environment and opportunities for monetary savings from increased efficiency, but its underlying goal also advocates quality, ensuring that we make buildings that will last over time. In many cases greener buildings can provide a better means of weathering the aftermath of the storm, leaving us better prepared for the inherent variability of nature.
Storm Planning 2.0
As far is the code is concerned, the current measures taken for buildings most prone to hurricanes are focused on reducing the damage done by extremely high winds. Along most of our coastlines, states maintain high wind zones that require new buildings to be prepared for wind speeds that can range from 90 to 120+ miles per hour.
For a project that I worked on near the Rhode Island coast this meant that structural measures were required to anchor the house to the ground and fortify against uplifting wind forces that can rip off roofs or even remove the entire house altogether. A steel frames was added on the side of the house facing prevailing winds while long steel rods were installed through the walls at various points from the roof all the way down to the concrete slab, effectively tying the roof down to the ground. Additionally, all windows were made with impact glass that was rated for projectiles so they would not shatter in hurricane winds.
Recent footage from New Jersey can point to why these measures are worthwhile. They can make the difference between a house that is damaged and completely beyond repair. However, their intended focus is somewhat narrow and once the house has survived the brute force of the storm nothing is helping people hold out inside while infrastructure is repaired. Furthermore, in our cities, buildings are often large enough and heavy enough that the biggest threats are not the buildings being blown away. With a little bit of planning we can preemptively cover more ground.
Storms in Cities
Though urban living has many accolades, a natural event can magnify how much modern residents rely on the continuous flow of energy. Once the power goes out, we are pointedly reminded what it takes to facilitate living in vertically dense development patterns. Sure, the lights go out and the fridge starts getting warm, but that is par for the course just about anywhere. The next thing you remember is that elevators need power, and you (read: I) live on the 10th floor. The value of those great southern exposures can quickly be questioned for a least a little while, but regardless, trips to the street become heavily rationed.
The next realization is that pumping water away from the earth takes energy as well. While suburban homes could still have running water through a power outage due to pressure provided at the distribution level, high rise buildings are required to add pressure to get water up to higher floors. When power for the pumps goes, so does water to faucets, showers and most importantly toilets.
When you add in the loss of subway and bus travel, storm events like Sandy can quickly cripple a city by stripping away all the facilities that allow it to maintain its unique functional patterns. However, greener cities with more sustainable buildings can begin to create a buffer for these events, providing increased comfort and safety for residents while the damage from the storm is mitigated.
A great place to start is renewable energy paired with measures of power storage. The only truly sustainable way to utilize renewables like solar and wind power is to supplement their erratic nature with base power storage to help smooth the crests and troughs of their intermittent energy sources. Renewable installations could be installed to help provide emergency power throughout a storm event–we certainly had more than enough wind to go around–and help run the essentials. In my building, the batteries for the lights in the fire stairs lasted less than a day, but they could have easily been sustained with a dedicated small scale wind turbine or solar cells on the roof. For the rest of the year, power storage also helps maintain a steady flow of power potentially sold to the grid with increased reliability.
When we knew in New York that power loss was likely the building advised everyone to start filling their bathtubs to use for extra water until power to the pumps was restored. Direct power storage could be used the same way, essentially turning on the faucet from the power company while the juice was still flowing to extend the amount of time the building could last on its own to run only the essential systems.
Pair this concept with a building that uses less energy all together, especially the core components, and now you’re really talking. The basic systems in urban buildings can draw a lot of energy; things like elevators, chillers, cooling towers, pumps and common area lighting. When specifying equipment , the efficiency of these systems could make the difference in how long the building can function itself when the grid shuts down. We have great access to elevators with regenerative drives that use power to go up, but gain power back on the way down (like breaking in a hybrid car). One Bryant Park has Otis “Gen2″ elevators that produce energy with every trip down. We can also use means of heat recovery and a tighter exterior envelope to decrease the size of mechanical systems. A smaller power appetite means that renewable sources and power storage could limit the time that we are completely cut off. Speaking from experience, I can say that the difference between one day without water and two (let alone more) is a big one.
When access to water becomes more difficult we quickly covet the resource that we normally take for granted. We can allay part of this with more water efficient fixtures like low-flow showerheads, faucets and toilets. When flushing the toilet means filling the tank manually from your bathtub water reserves, this becomes particularly important. On day three, extra layers of clothes and non-perishable eating habits have become accepted, but your eyes can’t help but weigh the falling level of the tub water in a gamble against how many times nature is going to call before the power is restored. In storm situations, however, the real difference can be made from what we capture on the roof and store to displace the need for potable supply.
In Hurricane Sandy’s case, the storm dropped up to 7 inches of rain on land in some places. Placing cisterns on upper floors or designing blue roofs that can hold water can provide rainwater for toilet make-up and let gravity do all of the heavy lifting. For an average sized New York residential building like mine, (say 60′x120′) that is 4,200 cubic feet of water–or over 31,400 gallons. With low flow toilets that’s over 25,000 flushes.
More the Same Than Different
In his NY Times opinion article, Andrew Zolli proposes that, “Where sustainability aims to put the world back into balance, resilience looks for ways to manage in an imbalanced world.” I’m not sure I agree. The clearest benchmark for sustainability that we have is natural systems, many of which are sustainable because they are resilient. Yes, the concept of sustainability is one of balance, but that balance is not an ever-steady constant rigidly adhering to equilibrium. Instead, it’s an oscillation to either side of a point of stasis made possible by ecosystems’ ability to bend, expand, contract and evolve. Natural systems survive because of their ability to respond and adapt to the inevitable variation of our planet.
It’s true that the relationship between sustainability and resiliency is very similar to the recent topic of green buildings vs. healthy buildings. The terms are certainly not interchangeable, but they are also not co-dependent. Given the breadth of qualities that sustainability encapsulates, it is possible to have a building that we label as sustainable, but not resilient. But more often than not the current of the two concepts is flowing in the same direction.
Sustainability revolves around achieving balance over the long term, but for us, being battered by the forces of nature is simply one more inevitable reality that will continue to occur over time. Designing environmental resiliency into our structures will also provide us with more resiliency against the harshest of environmental acts. Each year more disaster events show us that the recovery period can be just as costly as the disaster itself. Between the acts of wreckage and recovery we are searching for ways to provide relief, in effect we are helping residents buy time. Key services can be the difference between a lack of safety and discomfort. Making buildings that rely less on our infrastructural grid will inadvertently help their occupants endure longer when it is not there for them.
Image Credit: voxxi.com