What Is Resilience…and Is It Sustainable?George Middleton - Jul 2015
In a recent article, we examined the meaning of the term sustainability. According to many experts, including the United Nations and the U.S. Federal Government, sustainability is taking care of human needs today without compromising the ability of future generations to do the same.
In determining whether a material, product, system or technology is sustainable, emphasis needs to be placed on its environmental, economic and social impacts, both positive and negative. These are interdependent and overlapping criteria. When understood using the comprehensive life cycle assessment (LCA) criteria of inputs and outputs, the best and most sustainable outcomes result.
Today, our society and the design professionals who make our built environment possible have a whole new set of design criteria to consider. Sometimes referred to as ‘the next step in sustainability’ we must now also think in terms of resilience. What does this term actually mean, and can we understand it using some of the things we already know?
Resilience is used in connection with cities, systems, buildings, people, institutions and even products. Resilience has several meanings; classical definitions which come to mind and with which we need to be familiar in order to understand it. These include:
- Ability of a system to bounce back from stress, to spring back into shape
- Ability to adapt to adversity and to recover quickly from difficulty
- A measure of toughness and elasticity
- Withstanding stress, threats or catastrophe
- Resistance to failure, adversity, trauma, or tragedy
- Being strong, healthy and successful after disruption
- Surviving, adapting and growing regardless of the type of shock or chronic stress
- What are the stresses or events that can affect people and systems, causing them to need to be resilient in the first place? Potential stressors might include:
- Climate change, excessive or extended heat or cold
- Flooding due to excessive precipitation or sea level rise
- Fresh water shortage due to drought, contamination, reduced runoff, loss or waste
- Structure fires, forest, grass or range fires
- Air and water pollution, emissions
- High wind events, severe storms, tornados or hurricanes
- Civil unrest, political disruption, terrorism or sabotage
- Disease pathogens spread naturally or intentionally
- Population shifts, immigration, migration
- Market and economic shifts, change in employment
- Supply chain interruption
- Insect or animal migration, infestation
- Chemical spills, transportation accidents
- Economic disruption, failure or change in balance of trade
- Currency fluctuation or sudden devaluation
- Seismic or volcanic activity
- Solar flares, geomagnetic storms, asteroid impact
- Disruption of emergency blood, medicines or medical supplies
- Disruption or failure of power generation or distribution systems
- Disruption or failure of networks or communications systems
- Disruption of food production or distribution systems
In order to begin to understand the real meaning of resilience, we could divide up these potential stressors (and the potential responses to them) into manageable categories. Such a strategy might categorize stressors as:
- Short-term (sudden or shock) events
- Long-term (chronic or prolonged) events
- Expected events
- Unexpected events
The American Institute of Architects (AIA) states that it is committed to creating safe, secure, and resilient communities. “We provide our members with advocacy, research, and training to engage in all phases of disaster mitigation, response, recovery, and adaptation.” The AIA has recently adopted a broad and useful position statement on resilience, demonstrating its importance not only to its members but also to society at large:
“Buildings and communities are subjected to destructive forces from fire, storms, earthquakes, flooding, and even intentional attack. The challenges facing the built environment are evolving with climate change, environmental degradation, and population growth. Architects have a responsibility to design a resilient environment that can more successfully adapt to natural conditions and that can more readily absorb and recover from adverse events. The AIA supports policies, programs, and practices that promote adaptable and resilient buildings and communities.”
(Approved: December 2014 through December 9, 2017)
This statement recognizes that change is occurring in the built environment in response to new issues. It also implies that licensed architects will come under increased scrutiny because of their professional responsibility to protect the public health, safety and welfare. They should recommend and specify materials and products carefully so as to leverage attributes that are valued and desirable in terms of resilience including flexibility, efficiency, economy, speed, strength and durability.
The products and systems used in buildings and infrastructure should be considered so that the best methods of design and construction are used and all potential impacts from all potential stressor events are considered. There is a tendency to simplify resilience down to “hurricanes and seawalls” which addresses only one stressor and one response. But this approach is limited in value because it misses the point that resilience must be understood more broadly, so that people and communities are ready to survive, adapt and grow regardless of the type of shock or chronic stress that may occur.
Here are a few examples of various systems with emphasis on specific impacts and the desirable response attributes which can enhance resilience. This type of analysis should apply to all materials but for the moment we will consider vinyl (PVC) and some of the products made from it.
PVC pipe is used in water distribution systems as well as in drain, waste and vent applications. It can be used for storm water management and recovery systems. It is highly durable with a predicted service life of well over 100 years. It is flexible, sanitary and highly resistant to breakage, reducing water waste. It is potentially more resistant to seismic activity than systems made from brittle materials such as concrete or iron. Repairs are typically rapid and economical, minimizing disruption and cost to local communities.
Building cladding systems are potentially at risk in high wind events. When properly installed, vinyl siding is resistant to all but the most extreme weather exposure. Damage is relatively easy and economical to repair enabling rapid recovery of neighborhoods. Local housing stock can be inherently more flexible and adaptable, offering a longer service life since additions and modifications are more practical and economical than with other systems such as masonry. This product requires little maintenance over its service life and is immune to rotting and insect damage, which may occur with organic materials as insects migrate due to changes in weather patterns.
Vinyl membrane roofing is noted for its solar reflectivity which can have a dramatic effect on reducing building air conditioning loads and resulting energy consumption, utility costs, and electrical generation demand. Higher reflectivity can also help to minimize heat island effect in urban areas and is thought to have a positive effect on local microclimates. Roof systems are tested and approved to meet the strict wind-uplift criteria in building codes. This material is inherently self-extinguishing, enhancing its resistance to combustion and overall fire performance. PVC roof membranes can be the enabling technology in vegetated roof assemblies which can help keep cities cooler, generate oxygen and absorb carbon dioxide.
PVC is a reliable and high performing wire and cable insulation used in line voltage and low voltage applications in buildings and infrastructure. It is durable, resistant to damage in service, has high electrical resistance, wide thermal range and is self-extinguishing. Used in server farms, local networks and other digital application, this material is a contributor to making the Internet possible. This in turn enables a modern global digital economy to function. It also has many applications in radio communications networks and renewable energy generation and power distribution.
Vinyl facilitates healthcare and disease control through products that help to control infection, impacting the health of millions of people and the resilience of communities around the world every day. Vinyl flooring and other interior environmental surfaces in medical care facilities can be easily cleaned and disinfected. It is a well-known fact that PVC blood bags make a safe blood storage system possible, a resilience factor which is of no little importance in the event of a major stressor event.
Finally, the economic and social factors of resilience should be considered when evaluating materials and the products made from them. Vinyl-related manufacturing activity has many effects on local communities, beginning with providing steady employment. The many thousands of jobs along the entire value chain from manufacturing, to transportation, sales and distribution, installation, maintenance, repair and remodeling, disposal and recycling are all integral to the production and use of vinyl building products. Add to that the community development and provision of services made possible by the significant financial contribution of industry to local and national taxing entities. There are also potentially large global export and balance of trade impacts. Communities that are healthy economically are likely to be more resilient, enabling them to adapt to adversity and to recover quickly from difficulty, should that ever be required.