Passive Survivability

The northeast’s Blizzard of 1978 killed 54 people, destroyed over 2,000 homes, stranded more than 3,500 cars and caused over 1$ billion in damages.

In 1995, a heat wave that hit the midwest United States killed over 1,000 people, 700 of them in the Chicago area. For about a week in July of that year, temperatures were above 100 degrees during the day, and about 100 degrees at night.

A storm that covered much of the northeast United States and Canada with 1-2 inches of ice in January of 1998 knocked out power, telephone and water. 4 million were left without power, and over 600,000 people had to leave their homes for shelters.

In December of 1987, an ice storm hit Oklahoma, cutting off power to over 203,000 PSO customers. Over 100,000 of those customers were in Tulsa alone. The ice was so thick that the KTUL’s broadcasting tower collapsed, and there were several deaths from exposure and car accidents.

The most recent disaster, Hurrican Katrina, has prompted Alex Wilson, the executive editor and president of Environmental Building News, and the president of BuildingGreen, Inc. to promote a new phrase in conjunction with sustainable development – “passive survivability”.

The concept of this new term is that buildings can be built so that if their utilities are lost, the building will allow the occupants to survive.

Wilson recognizes that buildings can be equipped with generators or photovoltaic cells for minimal electrical needs, and that systems that collect and store rainwater can provide for water needs.

However, he cites several other “passive” ways that buildings can be designed to make the buildings more inhabitable during a disaster.

For example, reducing cooling loads on the building means that the loss of air conditioning need not be life threatening. This can be done by using shade, light colors, and more mass in the building envelope.

Natural ventilation is also important. Operable windows need to located to allow cross ventilation.

The building envelope – its walls and roof – need to be well insulated and energy efficient. If power is lost in the wintertime, this will allow the home to stay warm enough for occupants to survive.

Passive solar heat gain can provide some heat during the daytime, by allowing sunlight into the building onto surfaces that can absorb heat.

Plenty of windows are important for daylighting, so that light fixtures aren’t necessary during daytime.

Most of these sound like common sense things, and they are, but buildings have not been built with these features since air conditioning was invented. Most buildings are designed to be very tight, and become very uncomfortable within minutes after power is lost, especially in summertime.

One example from Katrina is the Superdome, where thousands of people took refuge during and after the storm. Temperatures inside the structure rose to 105 degrees when the power went out.

In the old days, when we did not have electricity or air conditioning, buildings were designed with some of the passive heating and cooling techniques that Wilson now espouses. Covered porches for shade, windows located to catch the prevailing winds, and high ceilings that allow air to stratify within a room are just a few.

Beyond being able to survive a natural disaster, passive survivability design techniques can have other benefits.

They can reduce the demand for energy, which can take a lot of pressure off of our aging power grids, as well as reducing our need for fossil fuels. This can help wean us from our dependency on foreign oil supplies.

It also means that if our power grid were the target of a terrorist attack, the loss of power would not necessarily lead to the massive loss of life, at least not right away. If our first responders have fewer emergencies to deal with in a terrorist attack, they will be able to stabilize things much quicker.

It will take a lot of time to incorporate passive survivability techniques into our nation’s buildings, but it has already begun in the reconstruction of the southeast coast where Katrina wiped out so many buildings.