Enclosure Advances Address Severe Weather
By C.C. Sullivan
Mark Twain remarked in 1897 that “while everyone talked about the weather, nobody seemed to do anything about it.”
Things have changed. Ever since the 2005 season – which brought the United States more than twice as many named storms and hurricanes as in an average season, according to NOAA’s Climate Prediction Center – building professionals, product manufacturers, and codes officials have worked to produce tougher buildings. New techniques and regulations introduced since the year of Katrina make buildings better at resisting projectile impact, wind-driven rain and high pressure differentials.
This has been driven in part to protect human lives, as well as to stem financial losses. According to the National Association of Home Builders (NAHB), Washington, D.C., seven of the 10 most costly natural disasters in the United States have occurred since August of 2004. Insurance companies have paid out a staggering $40.6 billion in claims in six different states due to Hurricanes Katrina and Rita alone.
Experts such as Dr. Robert Hartwig…
[SIZE=1][COLOR=#000]More hurricanes and severe weather are the trend, according to scientists at NOAA and elsewhere. In this visible spectra satellite image, the extent of Hurricane Hugo is seen on September 21, 1989. (Courtesy the National Hurricane Center/NOAA.)[/COLOR][/SIZE]
Airing Out: More Codes Call for Air Barriers
By PROTECT Staff
Have you specified any air barriers lately? If not, chances are you will soon. Recognizing the role that air barriers play in increasing energy efficiency in buildings, more codes are now including building envelope provisions. New rules concerning air barriers have taken effect in a growing number of municipalities and in states like Massachusetts, Wisconsin
*StoGuard Waterproofing/Air Barrier with Sto Gold Coat, “Steel Frame with Brick Veneer” Detail No. 20.00dG, 2007. SOURCE: Sto Corp. *
and Michigan. The International Energy Conservation Code (IECC) also calls for air barriers, and several federal agencies now require them.
Up to 40% of energy used to heat and cool buildings, says the Department of Energy, results from uncontrolled air leakage. Air barriers can conserve energy by 30% to 40% in heating climates, and 10% to 20% in cooling climates…
**ENCLOSURE DESIGN: **
Ways to Win: Condensation Design Strategies
For more reliable envelope designs use an integrated approach. This includes:
1. Control Driving Forces. Reduce the forces that drive water vapor through the envelope. High humidity levels in the ambient air should be reduced through dehumidifi cation and/or mechanical ventilation. Mechanical systems should provide complementary pressure control to minimize condensation potential.
2. Select Durable Materials. Building envelope materials located at potential condensation planes should not be…