Passive survivability

This term has come to the fore in the USA and elsewhere in recent months largely as a result of hurricane Katrina, which devastated New Orleans and the Gulf coast last August. The concept is that buildings should be designed so that they can survive the loss of essential services — electricity, piped water, sewerage — in the event of a natural disaster.

The term has been borrowed from an older military sense of measures being taken to ensure that military vehicles survived being attacked. In the buildings sense it came out of a post-hurricane reconstruction conference held in Atlanta in November 2005. This led to a set of proposals with the title The New Orleans Principles. One of these states, “Provide for passive survivability: Homes, schools, public buildings, and neighborhoods should be designed and built or rebuilt to serve as livable refuges in the event of crisis or breakdown of energy, water, and sewer systems”. Techniques include many that are also advocated by green campaigners: use natural ventilation, heavily insulate buildings against heat loss, use natural daylight, collect and store rainwater, install solar electricity generation, and so on.

Advocates point to the risk of terrorism that might lead to similar losses of public services. They also argue that possible shortages of fuel in decades to come will require buildings to use much less energy than they do now.

There is now talk among some enlightened architects of incorporating “passive survivability” into their designs — the ability of a building to operate on its own should systems such as water and electricity ever fail by, for example, using better “thermal envelopes”, natural daylighting and rainwater storage.

Guardian, 20 Jun. 2006

Passive-survivability measures are so important that it may make sense to incorporate them into building codes. Most, but not all, passive-survivability features will add some cost to a building, so the impact on affordability needs to be considered if such measures are to be required by code.

HPAC Engineering, Jan. 2006