|
Aligned with the rest of our nation, architects like us watched the unfolding events surrounding hurricanes Harvey and Irma with dread and fingers crossed that as little damage and injury possible would be wrought by these historically massive storms. As the news poured out about the impacts there was the resignation that the damage that occurred had to be accepted and it was hoped that the damaged communities could be healed more quickly than first reports would indicate. As this is being written, the US has had one of the most destructive hurricane seasons on record and Puerto Rico is facing a devastating, slow and painful recovery.
Losses from increasingly extreme climatic conditions are mounting in recent years for the US and for numerous nations, with many people from the front lines to those who must bear the repeated financial burdens to repair and rebuild, looking harder at how they can lessen these heavy losses. A great many people via the media recently recalled the devastation of hurricane Andrew when Irma was bearing down and inflicting damage on Florida and the neighboring states and islands. Andrew struck Florida in August of 1992 with Category five sustained winds of 165 mph and was the costliest hurricane to land in the US until Katrina in 2005. In comparison, Irma packed up to five times the energy of Andrew based on its size per NOAA and various modelers and meteorologists. By one measure, the hurricane force wind diameter of Andrew was 50 miles versus Irma’s 126 miles when they struck the Florida coast.
Image: NOAA
However, there may be some positive news to discuss. Because the losses from Andrew were so intense, it triggered a level-headed response from the stakeholder communities and this resulted in noteworthy improvements to the building codes and related guidelines and standards applicable to coastal areas at risk from hurricanes, and far better enforcement of the building codes. Besides building structural improvements, these changes also meant big improvements in the testing and systematic rating of buildings components like roofs, windows, cladding, and doors. Improved components included the use of missile-impact resisting glass that can withstand high-velocity impact from debris during hurricanes. Stick-framed housing, especially vulnerable to hurricanes, was no longer permitted in some areas. Backup generators for essential services became commonplace. Improvements were again made after category four hurricane Wilma struck Florida in October 2005, when glass breakage was higher than expected considering previous improvements and more recently loose stone (ballasted) covered roofs were more strictly regulated as wind-driven stones can be a considerable hazard. These reasonable improvements arguably make a big difference. The Notice of Approval (NOA) program has been incorporated into the Florida Building code and all exterior systems and components must be tested before being allowed to be used on a structure that requires a building permit. Tested assemblies are uploaded to a public database called the NOA and architects can search this information to select tested systems
Today it is far too early to assess or even summarize how the damage from Irma could have been worse if the improvements made after Andrew and Wilma were not in place. But anecdotally, one need only spend a little time watching the mountain of video taken when Irma was whipping through areas with glass high-rises to see how durable the construction was. High winds appear to have taken a far smaller toll on many building enclosures hit by Irma than they did in when Andrew struck. Though Irma weakened to a category four before striking the Florida coast, some of the areas it hit had a great many more glass high-rises than in 1992 adding far more construction into harm’s way. And since wind speeds at upper floors are higher than ground level winds, the challenges faced would have been greater for these high-rises. For instance, sustained ground level wind speeds are around 17 percent greater at the 25th floor than at ground level. So a 150 mph ground level wind would be over 175 mph at the 25th floor.
As hurricanes become far larger and even occur in swarms of storms during peak climate cycles, the risk of massive losses and tragedy escalate. However, those risks have been reduced from previous code improvements and can continue to be introduced, helping to limit losses and shorten recovery periods. The reasonable changes already made in the model codes can be adopted in more high-risk areas, where they are not now adopted. Current model codes can also be adopted more quickly where older codes are still being used for years after model codes and related guidelines and standards were improved.
Image: US Navy
Through the generations, building codes have been developed and improved. Usually, the improvements were driven by tragic events like fires, storms, or earthquakes; but a great deal of tragedy was then avoided after these improvements were made, in the forms of less damage and reduced loss of life and limb. Though they face the threats of wind damage and flooding quite differently, codes can continue to be adjusted to maintain reasonable levels of resilience to the hazards. The positive side of these well-reasoned improvements is an investment into the future of our communities where losses can be reduced or even eliminated.
However, where flooding is concerned, the US and numerous nations are arguably far behind in applying the reasoned advances discussed above. The tools to address flooding have been known for centuries and practiced with some success in different parts of the world. They include planning communities outside known flood areas, which was never an easy task since little data was available to community planners long ago. While access to the edge of the water was essential for economic activity and at times defense, the ageless intangible desire to be near the water was also a factor. Coping tools included buildings on piles or plinths in various forms, building critical structures like defensive structures floodproof while letting lesser structures succumb, and using building materials such as solid stone and large timbers that could be flooded and reused after drying. Some nations like The Netherlands became experts at levee systems and controlled flooding areas that helped keep them dry despite being below sea level. We can see some of these methods in place around our nation with shore homes raised on piles, larger buildings with sacrificial first floors that can be flooded out without risk to the structural frame and life safety, levee systems in place protecting parts of cities like New Orleans, and essential services in flood-proof structures or raised on plinths to continue operating during flooding.
But as with hurricanes, flooding risks are expanding greatly for many areas including places once thought reasonably well protected. This is in great part due to major changes in rain patterns driven by a quickly warming atmosphere that now can hold a great deal more water for rain than in past years. Flash flooding is more common, even in arid areas, as are shoreline floods where the rain from storms deluges fill rivers at the same time storm surges are forcing water levels higher at the outlets of these rivers, magnifying the flooding far past previous records.
Image: NOAA
The primary means to deal with flooding damage in our nation has been the use of flood risk maps and flood insurance programs such as the National Flood Insurance Program run by FEMA and currently up for reauthorization. This has never been easy but the risks may no longer be manageable in this way. 500-year and 800-year floods are frequent, even annual in many places, leaving many to question the value of this metric entirely. Flood insurance is widely reported to be unaffordable for a great many people living and working in locations at greater risk, meaning they are not protected and the higher premiums are not encouraging people to create more resilient conditions on their own. Real change is needed and while identifying options for new communities is not that difficult, identifying options for existing communities at risk is extremely difficult. It is one of the great challenges of our time and will take a wide range of stakeholders to resolve.
To close on good news, the changes made to the codes after Andrew certainly seen by some to be deal breakers in adding cost and complexity to historically low-cost construction areas. But plainly those fears held no water since coastal development exploded in the last 25 years since Andrew. It can even be argued that investment and development were strongly encouraged because some of the risks were being addressed by the codes and the building officials. This same logic could apply equally to design and enforcement addressing flooding risks. There is much work to do but the ability of stakeholders to meet previous challenges suggests what we face now can also be met. We can get these things done.
|