States must now certify that their building codes meet tougher energy-efficiency requirements under a new determination by the U.S. Dept. of Energy. DOE says it has established the latest standard from the American National Standards Institute/American Society of Heating, Refrigerating and Air-Conditioning Engineers, Standard 90.1-2004, as the commercial building reference standard for state building energy codes.
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.